Hi, Im a new member here, just recently clued into this forum. This seems like the place to be for people who are not content just driving their car!

Ive currently got an experimental project going on moving a 1984 190E 5-speed guts into a 1981 240D bellhousing/gearbox and then mounting it to my 83 turbo 617.
Ive already got a 4 speed in there for about 12-14 thousand miles and I hope to add an overdrive since I do a lot of highway driving. Ive already jumped the top speed a little with a 2.88 rear end and taller tires.

Im pretty far along with the project, and hopefully, barring any more milking by the machine shop, I should be close to seeing if it works. So far, ive got parts of both bell housings welded to each other, holes being bored out, and possible issues making the clutch work properly BUT, if it works, the actual modification to the bellhousing is not that bad.

Here is the link, http://mbca.cartama.net/showthread.php?t=25655

(I don't know if the pictures will be accessible, if not I will repost them here)

Any advice or opinions would be much appreciated, especially by anyone who has already tried this caper!


MOD EDIT per dropnosky's request. The method listed in the first few posts is NOT cost effective and he recommends starting at post #47 for round 2. I think we ALL appreciate his endeavors in this area.

You are clearly insane. Welcome to the board! Would it not just be easier to chop off the bellhousing?

maybe a little insane. I am absolutely committed to getting a 5 speed in my car, and I don't have the cash to order one out of the country, or really the time to search in yards for a golden egg. Its become an psychotic obsession.

Actually, just chopping the bell housings and swapping them was my first intention when I bought both trannys, but there were a couple of reasons why I ended up not going that way.

Mainly it was the potential difficulty of not making it perfectly straight or keeping the depth level. There was also the problem of just the one reference angle on the bell housing bolt flange which made the whole thing risky.

I originally started to break them both down in order to create two reference angles so I could make a jig to keep them both straight, and at that point, decided that if I cut the idler gear shaft supporting corner off, I won't have to worry about cutting the full bell housing,

In short, surprisingly, swapping the ends of the bell housing was more work with less control over squareness than the direction Ive gone so far.

Going off your signature, you'll find this website it right up your alley. Good luck on sourcing a 5 speed. Now, I have seen getrag 5's in a '80s bmw 5 series as well as a volvo 740i. Mating them to a 617, thats the fun part.

here are some of the pics from the other thread off MBCA and a short summary of project events- (my very low computer competence means that i was unable to bring the pics over with the other thread)

below- both the trannys-        

Both housings from the 1981 240 and the 1984 190 are very different, BUT, they share exactly the same length from the housing bolt pattern to the backing plate off the rear. Additionally, the backing plate bolt patterns are identical. My plan was to see if I could slide out the guts of the 5-speed, and mount them inside the 4-speed bellhousing/gearbox. I bought both trannys for 350 bucks. My goal was to see if I could build a working overdrive transmission for a 617 for low cost out of readily available MB junkyard parts in the US.

I ripped both transmissions down and put the housings side by side. There were a couple of big differences, three physical changes to the housing itself, and one external change in order to possibly get this to work.

1- The 84 5-speed uses tapered roller bearings, instead of regular roller bearings in the 81 4-speed.

here are the two gear sets, notice the tapered bearings on the 5-speed-        

The input and countershaft front bearing diameters are slightly larger for the 5-speed, so the front two holes have to be enlarged in the 240 housing (where I am currently at in the project). Also, there is a lip on the 240 housing for the countershaft front bearing that had to be removed, the 5-speed uses adjustable shims instead.

here you can see the difference on the front, the 240 is cleaner-    

2- The idler reverse gear shaft on the 4-speed extends backwards off a spacer plate, while the existence of overdrive on the 5-speed meant that the same shaft extends forwards into the bellhousing/gearbox. The casting has been modified to reflect this change, and support the idler shaft. To change that, I cut the corners off of both housings, and swapped them, welding the 190 idler support onto the 240 housing.

There is a fluid passage above the input shaft on the 190 which has to be duplicated in the 240. It connects the front seal plate area with the body of the tranny. I intend to drill this out when the housing gets back.

Theoretically, thats all that need to be done to cram the overdrive into the 240 housing. I am going to do a dry fit when the housing gets back so I can say for sure.

Thats it hopefully for internals, on the outside, the input shafts were different lengths, but both use the same pilot bearing, so I may have to work out some kind of spacer, as well as using a clutch disc for a 190.

Can you post the pictures here please? MBCA is one of the forums I try to avoid.

EDIT: Never mind, it looks like you posted them just as I was replying!

sorry, Im getting called away from posting by a pushy female, I will add the rest of the pics later tonight when I get back.

Ok, to continue, first let me apologize for confusing picture problems and thread weirdness, Im just getting the hang of the picture insert function.

Again, both bell housings from the front with the guts removed-        
here you can see the differences, the dirty one is the 190, clean 240. The 240 will need to be slightly enlarged on both holes as well as the visible lip removed. The input shaft cover plate does match up, with the exception of what will be an overhand up top. Depending on how the gasket is designed, I may ignore that.

Here you can see the idler gear shaft provision differences in the cases. The 190 still has the shaft installed.        

the same provision designed into the 4 speed, notice how the same shaft extend rearwards off this plate instead of forwards-    

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Making my first cut into the cases, it was important that the cuts be nearly identical for obvious reasons. This was the, "OK, now this is scrap metal unless it works" point in the project-    

Here are both cases with the corners removed, and the corners themselves separate-        

here is the 190 corner on the 240 case, what turned out to be kind of a plus was the separate molds for each case kind of gave the internal weld here and additional safety factor, on the 240, the extra cavity is open to the back, on the 190, the cavity is open forwards into the bellhousing. By swapping the corners, I created a closed space inside there, meaning that the internal weld is basically backed up by the external weld.-    

Here are some prep pics for welding, I cut down any gussets and put a 45 on all cuts for better weld penetration. I had an almost perfect fit on the sides, but the gap got a little larger on the bottom of the case, fortunately it did not turn out bad-    

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heres a better pic of the weld prep. I was super concerned that this be perfectly straight, so the plan was to fully bolt the idler shaft into the corner as well as bolting the corner to the backing plate. That gave me two reference points. It worked out pretty well, there is minimal tweakage-
   

And after having it welded. I decided that my pretty sparse aluminum welding experience meant that I had to find someone who would do it. I took it to a guy who does a lot of crack repairs on bellhousings for my employer. This guy did a great job, and it cost me only 40 bucks!
   
   

In this pic you can see the 240 case with 190 corner and 190 backing plates attached, everything went together pretty well-
   

That kind of brings us up to speed as to where I am now. The case is currently at a machine shop who is supposed to be fly cutting the shaft holes, but is glacially slow. Once I get it back, I can say definitively whether or not this will will work as far as the guts swap, or If I now have about 30 paper weights.

OK, according to the milkmaid machinist, I can look for the housing back as soon as tomorrow. His original finish date was the friday before last, the thing has been there just shy of 3 weeks. I can only hope he remembers what hes supposed to be doing and does not back a forklift over it. (this is my little rant, sorry)

Here are the diameter numbers which I did no have on hand earlier-
The input shaft hole on the 240 is 2.688 inches , and needs to be enlarged to 2.719

The counter shaft hole is 2.045 inches and needs to be enlarged to 2.064 as well as losing the roller bearing lip.

Ok, so here is my (perhaps not so intelligent) question. Why not find some new bearings that would fit the shaft and the hole?

Mostly it was a decision based on the construction of the 190 trans. It was a lot easier to take apart and had a lot less snap rings, I think 1 or 2. The counter shaft and input shaft also have a shimmable spec on the tapered bearings as opposed to the snap and go feature of the 240. The outer race has to be able to slide in and out of the bore in order to properly reassemble with the correct specifications and possible preloads.

I suppose I could press the bearings off the counter and input shafts and try to use standard roller bearings, but then that might change the original design and load tolerances in the 190 guts, plus the shaft diameters and lengths are somewhat different.

Basically, my fear was that if I try to make the 190 parts fit the 240 case, I might inadvertently damage the function of the actual trans. With that in mind, I have been trying to make everything go the other way, making the 240 case fit the 190 parts. That way, in the end, I have a standard 190 trans identical to other trans of the same year that just happens to be in a different wrapper. IF this works, It will hopefully be much easier for future repairs and maintenance.

(04-23-2009 08:13 PM)dropnosky Wrote:  ... making the 240 case fit the 190 parts. That way, in the end, I have a standard 190 trans identical to other trans of the same year that just happens to be in a different wrapper. IF this works, It will hopefully be much easier for future repairs and maintenance.

Yep, I would of done the same. Great job so far though!

Keep us posted.

Any updates? You have renewed my interest in rebuilding my 5spd. I need to find a decent 4 speed to cannabalize.

FINALLY got the housing back on monday after 4 weeks. The consolation is that the machinist did a good job, and put a very nice sliding tolerance on the bores with absolutely no play. IN the end, it cost 75 bucks for the two holes to be bored out.

Here is a pic of the 240 housing and the tapered 190 bearing races
   
Here are a few pics of the 240 and 190 front cover plates, they have identical bolt patterns, and the 190 will fit fine on the 240. I have to drill the different fluid provision into the 240 case, but it should work the same way slightly lower.
   
Notice the fluid provision difference here, otherwise they are nearly identical
   
Here is the 190 cover on the 240 housing, It looks like the overhang that I feared will be minimal, and I will have space to drill in without too much difficulty
   
From the inside of the case, the holes are very close to dead on, which was a relief. This is looking down at the 190 cover bolted on.
   

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An interesting difference between the two transmissions is this fluid impeller here on the output shaft where it meets the input on the 5-speed. When assembled, its almost fully encased and must act as an oil pump. I wonder if they had some failure problems at one point. (you can see here one of the parts I destroyed taking the thing apart, this stud for the other side of the shifting mechanism was basically welded to the case and I bent it way up getting it off. Fortunately, there are spares from the 240 case.
   
Here are a few pics of reassembly, the input and counter shaft installed, and then the output shaft partially installed-
   
   
This is a pic of one of the detent mechanism, you can see here I actually installed the spring behind the lever upside down first, which caused a few issues.
   

I took it to work and did some further reassembly, I need to rethread the bottom drainplug, which was warped slightly with welding, but it seems to be going together normally. The detent mechanisms are lining up properly so far.

With a grain of salt, it seems like it might work, but its been a pretty full workload this week, so I have not completely reassembled it. Ill know for sure later this week and have some further reassembly pics.

Again Great Job. This is very encouraging.

Thanks! Im hitting a brick wall trying to find gaskets and shims though, the first two places fell through, anybody have any good places they know of?

Classic Parts.

Did you get new syncros as well?

Does classic parts have a website or do you have a phone number for them? I did an internet search and came up with quite a few choices.

I did not buy new synchros, actually, the 5-speed is in surprisingly good shape inside. The only real wear is on the leading edge of the idler gear, and not that bad at all. The synchros still even have machine marks on them. I though originally that the countershaft forward bearing was toasted, but after cleaning, its rolls well, probably some crud from disassembly.
Actually, I think that the transmission was rebuilt at some point fairly recently. Its got a US and an English bearing in it, as well as German.

I got both transmissions on the cheap from two separate junkyards. The 240 was a hundred bucks and had "reverse problems" as you can see-
   
Someone forgot that reverse was not syncro and toasted the output shaft here. The gear itself has no damage. The 190 was 250 bucks, and was stated as healthy, which looks to be true so far.
I need to get a reassembly diagram, since Im having a little trouble with the correct procedure, I can fully reassemble the trans and everything fits, but I cannot get the second shift fork to move afterwards, although it does fit apparently correct. It seems to be bound on something, either a reference problem with the countershaft, or a problem with the detent mechanism. Probably a bit of both, since the countershaft needs to be shimmed up a little to be at the right height with the input. When you set the countershaft in the bore, its too low and hits the input shaft bearing slightly, which is probably causing all this mayhem.

Project is now on a backburner for the moment because necessity to repair the braking system, which has moved past annoying into deadly.

http://mbca.cartama.net/forumdisplay.php?f=84 is what you are looking for.

When you are done do you want to rebuild mine

Is there a way to adapt the electric over drive out of an old Volvo to the 4spd Mercedes box? some of the old Volvos had an overdrive 5spd switch on the shifter in the old Volvo 240s just curious how different that trans is?

(05-04-2009 08:35 PM)willbhere4u Wrote:  Is there a way to adapt the electric over drive out of an old Volvo to the 4spd Mercedes box? some of the old Volvos had an overdrive 5spd switch on the shifter in the old Volvo 240s just curious how different that trans is?

The Volvo guys, from what I remember, weren't thrilled with it. Many converted to Getrag 5 speeds.

Speaking of which, y'know, there are companies out there who specialize in this kind of thing - custom adaption bellhousings. Lakewood does it, I think.

The best five speed I've seen are the Toyota's from the 80's on up. Takes 350 lb ft of torque, seen them live behind built 383's and the like, and they're cheap. Shift a hell of a lot better than the Mercedes box does, too. There's an R version good for about 420 lb ft. RWD Celicas, Supras, five speed Lexus models.

Hell, I don't doubt a BW T5 would probably qualify as an improvement over the Mercedes box. Not the most sought-after box either.

This whole thread is interesting, though, would like to see how it all turns out.

I had a Getrag 265 5spd behind my 1984 BMW 745i turbo that pushed nearly 450hp it lasted just fine I rebuilt it before I swapped it in there and cranked up the boost!!!

Contacted classic parts, they can get me the rebuild kit, and apparently just about any widget I may desire! Thanks for the tip. They also may be able to get a reassembly procedure for that chassis/trans, which would be great.

Fixed the brakes, both inner pistons on both sides rusted into the bores and consequently ended up boiling the older brake fluid on the outer piston during hard braking. Ended up with no brakes in the fast lane on a 4 lane/4 lane intersection doing about 30. Fortunately was able to make a hard right across traffic and roll to a stop without killing anyone. Unfortunately, that passenger won't ride in the car again. All new front braking parts installed, and shes back on the road.

(05-18-2009 09:05 AM)dropnosky Wrote:  Unfortunately, that passenger won't ride in the car again.

would that passenger happen to be of the 'female persuasion'

btw... this is probably one of the best ideas and executions (so far) that ive seen... great thread!

dropnosky, WAY cool project. I wouldn't have even dreamed of trying this! There are a lot of benefits to having a drop-in transmission and I can totally see the benefit.

(05-13-2009 09:30 PM)CID Vicious Wrote:  The best five speed I've seen are the Toyota's from the 80's on up. Takes 350 lb ft of torque, seen them live behind built 383's

That is encouraging news. There is a thread here where a guy put a 617 in front of a toyota truck transmission. Used the toyota flywheel and toyota starter, and the toyota bell (the starter bolts to the bell, just like the mercedes, in the correct place!). Made an adapter from bell to block. Seems like it might not be a very big deal to put a toyota trans in a mercedes car. It would be a matter of making the driveshaft work, mounting it, and working out the shifter.

(05-18-2009 09:05 AM)dropnosky Wrote:  Contacted classic parts, they can get me the rebuild kit, and apparently just about any widget I may desire! Thanks for the tip. They also may be able to get a reassembly procedure for that chassis/trans, which would be great.

Did you talk to Tom? He's a great guy hands down. If you get a tear down doc on the trans pass it over.

Thanks for all the response! I did talk to Tom through email, he was very courteous and helpful. He managed to get a gasket kit for me which I received today, but I have not heard anything on the reassembly diagram, so I am assuming no on that. I need to contact him back and ask.

Ill just have to play it by ear with reassembly at this point and just do it by feel. I need to bring the tranny home so I can make progress, its been kind of a hectic month and nothing is getting done at work.

a couple of pics of the gasket kit and a part number, which as 65 bucks with shipping.

   
   

sweet.... im looking forward to your results!

Got the 201 chassis repair catalog. Has every piece of information on the car and engine you could want, EXCEPT any info on the trans. That must be on its own specific CD.

(05-20-2009 11:07 AM)GREASY_BEAST Wrote:  dropnosky, WAY cool project. I wouldn't have even dreamed of trying this! There are a lot of benefits to having a drop-in transmission and I can totally see the benefit.

(05-13-2009 09:30 PM)CID Vicious Wrote:  The best five speed I've seen are the Toyota's from the 80's on up. Takes 350 lb ft of torque, seen them live behind built 383's

That is encouraging news. There is a thread here where a guy put a 617 in front of a toyota truck transmission. Used the toyota flywheel and toyota starter, and the toyota bell (the starter bolts to the bell, just like the mercedes, in the correct place!). Made an adapter from bell to block. Seems like it might not be a very big deal to put a toyota trans in a mercedes car. It would be a matter of making the driveshaft work, mounting it, and working out the shifter.

That is good news. I've had three cars with that trans and they shift really nice and easy, far, far better than the 240D, and they made a variety of gear spreads to work with. Thanks for bringing that to my attention - because if I can put a 617a/5speed in to replace the 616/4spd, then I have that 616/4spd for another application - shop truck? Would probably be awesome in an old S10 or LUV. Or an ancient Datsun from the 60s.

That they almost look like they go together is freaky, thankfully the Japanese were tasty thieves .

The 'stock' approach is a great idea too, I think of it this way: most of us would like a 5 speed, wouldn't it be nice if we had three or four versions to pick from so we can be 'in accord' with our local junkyard supply? I feel bad for MB guys out in the middle of Nowhere, America, I doubt I'd be so gung ho about MB if I didn't live Cali where they're plentiful. That's why I need to do my fun stuff here, if I decide to move back east . Get it while it's cheap!

Dropnosky, again, good catch, who knows how long it might have been for someone else to go, 'y'know, it's almost like these would go together...'

any progress on this yet?!?!? again cool project

Sorry, some explanation is in order. Project is on hold for the moment. Winmutt has provided a link to information on the tranny, but Ive had to put it aside until I am fully situated lifewise with a new job.

At the same time, the benz is broken on a lift at the old job, which I leave in two days. (its been there for a number of weeks now with different problems) Right now Ive got to get it fixed and out.

I should have everything sorted out in a couple of weeks.

cool man, keep us posted! congrats on the new job...

Ok, a couple of weeks turned into a couple of months, but I am now working on this project again. No more F-ing around. Streamlined a lot of personal stuff, sold the car, and now there is nothing left but myself and my beloved pile of mercedes transmission parts. This is as it should be.

Built a table for the transmissions and drilled out the fluid passage on the 190 case. Should work properly, pics to come.

sounds good what are you going to put it in???

My plan is to assemble an ideal list of drivetrain components and parts and eventually build another car up.

ideally, id like to get a couple of wrecked or rusted cars out of a yard and build something awesome, like maybe a two door wagon.

find an SL that would be bad ass I looked at a rusty one here in Colorado a 72 280SL 4spd for $2000 needed to much body work for me!

awesome dude... good to see that someone is getting serious with his project... ill find out in a couple of days (hopefully) whether or not these last 2+ yeas of school have been worth the effort... if not, I have until mid december before I fly out to meet the NIMITZ on deployment so Ill prolly drop out of school and get all my ducks in a row with my boat and car projects.

anyway, back on topic: I really look forward to your results!

Ok, two big things. One, after struggling off and on for weeks getting everything inside and having it not be able to shift, then taking it apart, a dim lightbulb finally went off.

The problem is one of clearance, but its totally based on the fact (humiliating) that I neglected to check the DEPTH of the castings on the bearing surfaces. The bores are the right size, the overall lengths of the housings are the same, the depth from the bellhousing bolt pattern to the 6 hole plate bolt pattern are the same, BUT the casting is a different thickness!

The 240 casting is a full 2-3 mm thicker on the front section where the bores are! OF COURSE it won't work! Elsewhere the casting is the same size, but on this specific part, its thicker. Back to the machine shop on monday.

Its not really all that clear, but here are a few comparison pics- Here you can see the 240 housing-
   
   

Here you can see the depth of the 190 housing-
   

Once this depth issue is resolved, I should be able to put it back together so it works.

2nd big thing, I was reading through this entire post and earlier on winmutt asked, "why not just cut the bell housings and weld one to the other?"
At the time my reason not to do that made sense, but its involved a complete teardown of the tranny and a lot of steps.

After thinking about, it occurs to me that there is a second easily usable reference surface on the outside of the tranny, the 6 hole cover plate inside the bearing surface!
With a nice enough jig, you could bolt it to that surface and to the bellhousing, then cut and weld to your hearts content without mucking about inside the gearbox. Since I have everything apart and the measurements will be easy, Im going to put together that jig next.

Heres a pic of initial jig plans for "Son of franken-5-speed" welding/cutting/scribing jig. Going to make this, then do a cost analysis of both processes. Any suggestions on jig design are much appreciated.
   

In this plan, once you remove the input shaft cover plate, you bolt the jig to the inner pattern, and to the outside bellhousing pattern. Then, if I can incorporate the scribe tool I want to build into it, you then scribe around the bell housing for your perfectly square cut.
Once cut, the plan is to take the jig and move it to the other bell housing and do the same thing. The outer ring will have bolt patterns for both housings.

Once thats done and you champher the bell housing edges, you bolt the jig with the 240 bolt pattern to the 190 gearbox and weld it perfectly square.

Here are some pics of drilling the hole for fluid passage on the 240 Case.

Not surprisingly, the 190 housing and gasket fluid hole provisions are not identical as you can see-
   

I decided to just make a round hole that fit into the gasket provision instead of completely duplicating the slotted hole on the 190 case. That hole is 50% blocked by the gasket anyway.

Here are a few pics of the process-
The 190 gasket on the 240 case-
   
Marked section that needs to be drilled-
   
Drilling the fluid hole, (this is bit #3 of the drilling process, and I was very slow and light so as not to crack the housing)-
   
Once the hole was drilled it worked nicely with the gasket, I will have to ream out the hole for a smooth surface-
   

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I will definitely need to build up that outer edge with some aluminum. There is almost no surface for a good seal. First stop on monday is back to the welder, then to the machine shop. The drilled hole is actually larger than the usable area of the slotted hole, meaning more fluid will reach the front of tapered roller bearing. Not sure if it matters at all, but at least more than equal lubrication will take place this way.

In this pic, I filled in with sharpie where I need to add weld for the clamping surface-
   

Ok, MAJOR dimensional problem. In order for things to line up properly, I will have to space the case out almost a half inch. Its hard to describe, but we are talking the construction of a legendary jig to control squareness.

Even though this is reaching the level of madness, Im kinda committed to achieving some sort of success.

I think if I space it properly and make it square, I can make it work. In the end swapping the ends of the bell housings will definitely have been the easiest path, but ironically, at this point in the project, I would have to make a similar jig for both ideas, so Ill just continue down the chosen path.

Had the fluid hole provision weld added today- here are a few pics, cost an additional 10 bucks and will need to be fly cut, but welding guy came through again. Took him about 5 minutes.
   
   

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I must be out of my flipping mind, but here is my attempt to describe more clearly what im actually kinda looking forward to doing later.

The major dimensional problem is that the interior of the case is about a half inch too short on the 240. all bolt and shift holes are referenced on both housings off of the back plate. I can't just add a spacer on the back for this reason, especially since overdrive is controlled by a shift arm that extends through the backing plate.

What I will have to do is cut the housing in half about a quarter inch from the INSIDE of the bores on the case side of the housing. This is where the dimensional difference is, once I do that, I can expand the length of the case to incorporate the gear set and all other holes in the case will retain the correct dimension.

On the face of it, its not really that big a deal, the hard part comes into keeping it perfectly square for welding. By expanding the case, I create a possible risk of having the bores and backing plate seating surfaces slighty off. If that were the case, the transmission would eat through bearings probably within a few hundred miles.

Building the ultimate jig is everything, if I can't keep it perfect, then all this screwing around and parts become scrap metal and paper weights.

Ok, spent some quality time with a hacksaw and divided the housing where it needs to expand about a half inch. The real trick will be welding this back together-

Some pics of the two halves-
   
   
   
   
   

dropped off both halves to be fly cut flat by a new machine shop. They say it will be done ominously in a "while". I can now work on this jig.

Both transmission housings share two identical bolt patterns. 1 is the 6 hole input shaft cover plate pattern, and 2 is the 10 hole pattern on the end of the case. The trick is to build a jig that uses both patterns and maintains their orientation to eachother.

The 240 case needs to be 'stretched', its overall a little less than a half an inch shorter than the 190 case. The location of the stretch is in the center of the case, you can see from the cut pictures above.

Here is a 16 step list of what I need to do to complete this stretch before I can try again to see if this works.

1- I need to cut a piece of the 190 bell housing off so that I can slide the housing sideways off of a jig.
2- I need to manufacture a plate that matches the cover plate bolt pattern
3- I need to bolt this plate to the transmission, and weld some steel pieces that extend straight down out of the bell housing.
4- I need to clamp some cross pieces across the face of the bellhousing and weld the cross pieces to the steel that extends straight down.
5- I need to use the extra 240 backing plate and permanently attach it to another piece of steel across the top of the case.

At this point I will have steel pieces bolted to the 190 case that extend out far enough on either side that I can now weld more steel to them and create a rectangle of steel.

6- Once the general rectangle is secure, I need to weld gussets into all corners to prevent flex. I need to structurally reinforce the jig so that it does not move at all when the aluminum is being welded. This may require a third leg of the jig, Ill have to see.
7- Once the jig is complete, I can now slide the 190 housing out of it through the hole in the bell housing I made.
8- At this point I can now bolt in the fly cut pieces of the 240 transmission and measure precisely how much of a gap I need to fill in.
9- I need to make the spacer, Im thinking of about 3 different ways to do it right now, we will see when I get there.
10- Spacer will get welded to both sides of the 240 housing on the outside.
11- The jig will then have to be cut to get the housing out.
12- All other welding can now take place.
13- I clean out the weld areas and grind them back on the inside of the case for clearance.
14- The 240 case then returns to the machine shop to mill the inside of the front part of the case so it shares the same dimensions as the 190.
15- The cover plate bolt pattern then needs to be fly cut, (this will probably happen before the housing gets mounted to the jig)

16- I can then try and re-assemble the transmission. Ha Ha Ha!

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Here is a drawing that more clearly illustrates what needs to be done-

black represents the jig and hardware
Red represents the outside of the housing
blue represents the inside of the housing
green represents the spacer and weld location
   

Ok, project direction question.

As I see it, I have several directions I can go in.

1. I can continue down the most complicated path, the direction I am going in right now, and doggedly see this through to the finish following the steps listed above just to see If I can. This would be the most technically challenging route, and the most expensive with the most machine time and least guarantee of results.

2. I can cut the reverse idler corner back off of the 240, re-weld it to the 190, and build a jig to swap bell housings and follow that direction. This would be cheaper and easier, and probably be a 100% guarantee of success , but I would also have to admit defeat.

3. I can theoretically continue down path 1 all the way until it either works or not, and then follow path 2. Nothing in path 1 really invalidates a later completion of path 2. Definitely the most expensive option, but also the most informative on what can be done, and allows me to keep my pride.

Any thoughts?

I'd go 2. No point in going the hard way unless you have to or really want to.

After all you've invested, wouldn't it be easier to get an $800 euro 5-speed imported?

Agreed, I thought about this for a while last night, and decided that the most important thing here is achieving the end result of a 5 speed that bolts to the 617, not achieving the success of any particular METHOD that reaches that goal.
Add that to the fact that I have now spent a number of months pursuing the objective based on a path that was flawed from the beginning because of a bad measurement on my part. Continuing down a probably successful conclusion of option 1 would only be my attempt to MAKE it work, despite being initially wrong. The easiest, fastest, best, cheapest way should be the only way.

Option 2 it is. I am now going to re-start this thread from post 47 and return us back to post 2. The first 40 something posts will now be called "The importance of double and triple checking measurements before acting"

First a cost analysis of option 1 so far. Both methods will now be compared using the figure of 800 dollars for getting a gearbox from overseas (my source was about 1500 bucks, but I am willing to bet forcedinduction has a better one, so Ill go with his number)

Option 1 initial parts cost-
250- Used 1984 190 5-speed transmission
100- Used/damaged 1981 240 4-speed transmission
65- 1984 5-speed rebuild gasket set
40- W201 chassis CD which turned out to be unrelated to project, but bought for it.

Option 1 Welding costs-
40- Idler gear shaft provision weld
40- (estimate) Idler gear shaft provision weld back
10- gasket surface build up weld

Option 1 Machinist costs-
75- input and counter shaft matching boring.

That brings us to 620 bucks so far including returning the 190 bell housing to usable condition. To continue down the option 1 path will cost I estimate at least 200 bucks for the additional machining, and probably at least 200 bucks for an almost impossible weld.

Estimated costs would be 1020 bucks to complete option 1 without even calculating how I would make the spacer. If I can get one for 800 bucks that is not stitched together, whats the point? Personal time involved is not really calculable, but not as bad as you would imagine. the longest time I spent working on this at any one time was about 2.5 hours sawing the bellhousing completely in half. overall, option 1 is not worth it.



Starting costs for option 2-
250- Used 1984 190 5-speed transmission
100- Used/damaged 1981 240 4-speed transmission
65- 1984 5-speed rebuild gasket set

that puts me at 415 bucks so far, which we will need to add the cost of making a jig, and the bellhousing weld before we can see if it is cost effective.

Here are a few pics showing the 190 corner back on the 190 housing weld prep. Cutting it back off was a lot harder with the weld, and I was unable to totally control how straight the cut was, but it worked out ok even so.
   
   
   

Dropped it off this morning at the welder, the 190 case should be back at square one by the first of next week hopefully.

I also dropped by the machine shop and i'm having them create an exact bolt pattern duplicate of the input shaft cover plate for the jig out of 1/4 inch steel.

Next I was thinking about the input shaft problem that was still unresolved in method 1. Heres a comparison pic-
   

Initially, my plan was just to deal with it after putting the transmission together with some kind of spacer. They both use the exact same pilot bearing, but the 240 shaft is a lot longer, and another large factor is that the 240 clutch is a lot cheaper than the 190.
The best of both worlds would be if I could somehow swap the pertinent parts of the shafts. That way, every other clutch/drivetrain part could still be standard 240 stuff. I don't want to make it so any maintenance requires an extensive parts reference list.
With this in mind, I went to yet another machine shop recommended by the welder to see what can be done. The machinist tells me that we can try and swap the ends of the shafts. The procedure would be to cut both shafts, drill down the long axis and thread the pieces back together to weld it. The risk here is that the strength of the shaft is now completely based on the strength of the weld.
Also, how we proceed depends on the construction of the shaft itself. It is hardened steel on the outside, and possibly all the way through. If its hardened all the way through, then we have to consider different options on how to keep it properly straight.

He tells me that he has done this specifically about a dozen times with good success, but on low RPM, high torque farm equipment using the welder I am also using. Im not too worried about the strength if thats the case.
He is worried about the balance at high RPM, so I may look into resolving that later if this works. I have him cutting the 240 input shaft as an experiment to see how we can proceed.

Wow man! I've been looking forward to updates on this thread for a while. The jig looks like it wouldn't be too difficult to set up, and definitely something that you could create a CAD file for once you get the details figured out(for others far away who cant just 'borrow' it). Anyway, continue kicking ass man!

Thanks!

I felt bad about saying maybe 20 times, "I think this will work" earlier in the thread, and then disappearing for 4 months right after saying- "I just have to do this one thing, and we will know".

That would have really annoyed me had I been following the thread and waiting for some sort of outcome. The plan now is to consistently work on this until success or failure fairly speedily to make up for my earlier behavior.

At the moment, I am once again at the mercy of machine shops, but I learned a valuable lesson in the interim. EVERY one of these guys will take forever to do anything, so by spreading multiple parts of the same job out to a bunch of em, I can, A, cut down the lengthy wait time, and B, compare the performance of each one against the others.