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+--- Thread: Drive Shaft Repairs & Updates (/showthread.php?tid=2809)
Drive Shaft Repairs & Updates - Greazzer - 07-21-2011
About 3 weeks ago while driving home doing at least 70 mph my car had zero acceleration, no gears, nothing. After towing it home, I believed my transmission was shot. Not so. There is a nut that holds the transmission output flange. This put my car out of commission for 3 weeks. So, if you're ever just driving along and you have nothing, take a look at the output flange first. I have some pictures of the old one. It's toast.
My 1985 MB 300D Greazzer got some new parts, cost about $650, but I do have a new driveshaft, flex disks, output shaft and nut. Here are some pictures of the parts.
The driveshaft is modified. It has grease fittings where as the factory unit was a sealed unit. In so far as a solid, one piece driveshaft, I called around and the general consensus is that it can be done, but it will damage the transmission and differential. Not sure if its true or not. In any event, this was a royal PITA job. I am still not confident that the flex plates are on correctly. The bolts were incredibly difficult to tighten up and not sure if it was supposed to be that difficult. I am thinking about swapping out the bolts as I do not like the hex vs. regular bolt plus it was a choir just to tighten them up. Any ideas ???????????
RE: Drive Shaft Repairs & Updates - larsalan - 07-21-2011
I saw a picture one time, I think on dieselgiant. The front flex disc had failed and pretty well threw the drive shaft up through the center of the unibody. Looked pretty gruesome.
yeah, here it is.
http://www.dieselgiant.com/Mercedes%20flex%20disc%20failure.htm
RE: Drive Shaft Repairs & Updates - Biohazard - 07-21-2011
My output flange got borked too. I actually broke the output shaft from having to do an emergency weld job on it. Its back together now. You're right about it being a PITA. I fought mine apart and back together. The dowels on the flex discs just did NOT want to line up and slide into the flanges. I've used the regular hex head bolts and allen headed bolts for the flex discs. I think I liked the regular bolts just a little more.
RE: Drive Shaft Repairs & Updates - Greazzer - 07-25-2011
Still not 100% sure if I installed the flex disks correctly, but my ride is a lot smother. I still have a lot of throttle left, but the FSM says my trans will only handle 104 mph, so I did not want to push the old girl since she has a lot more miles than the odometer says. I finally got the odometer fixed by a dentist in CT who drilled a hole and inserted a pin in the gear onto the shfit.
Ooppsss ... forgot picture of odometer.. Sorry
RE: Drive Shaft Repairs & Updates - Captain America - 07-25-2011
Nice!
RE: Drive Shaft Repairs & Updates - Greazzer - 07-26-2011
So, I finally see one of the main reasons to upgrade the transmission. Assuming the FSM is accurate in that 104 mph is the limit, then having the world's best engine is really limited in that the stock trans can only handle 104 mph. I appreciate that one could possibly go over that without an issue, but with high miles, why risk a major problem? I wish there was a plug and play solution to the transmission issue. I see a lot of threads, however.
As for the transmission guru's out there, any way to start a definitive thread / stickie? I realize my driveshaft may be a waste of money if I get a different transmission, but I can now see how incredible this old, 5 cylinder engine is with minor tweaks .... I could have easily hit 105 mph on a flat road! I would further assume that if I adjusted my turbo (it's stock), installed my M+W injection system, 15" tires, 2.88 rear, and other minor mods, this engine could easily do 120 mph. Also, I am in the process of getting rid of most of the mechanical pumps -- switching over to electric steering, water, and vacuum pumps. Once I tackle these issues, and investigate carbon fiber panels, I am going to locate a race track and see if I can go all out and hit 140 mph as my goal.
RE: Drive Shaft Repairs & Updates - Captain America - 07-26-2011
The transmission isn't limited by mph...
But top speed for the car when its STOCK probly is 104.
hp mods, gears and such will change top speed but it doesn't mean the second you go over 104 the transmission will explode.
RE: Drive Shaft Repairs & Updates - garage - 07-27-2011
I had a w116 that hit 120 on the speedo numerous times, never had a problem with the tranny. Im not sure wich tranny was in the car though.
And that was running pure WVO
RE: Drive Shaft Repairs & Updates - Greazzer - 07-27-2011
I was running the grease when I hit 96 ....
RE: Drive Shaft Repairs & Updates - JB3 - 07-27-2011
(07-21-2011, 10:50 PM)Greazzer The driveshaft is modified. It has grease fittings where as the factory unit was a sealed unit. In so far as a solid, one piece driveshaft, I called around and the general consensus is that it can be done, but it will damage the transmission and differential. Not sure if its true or not.
The diff and engine and trans are in fixed position as far as forward and backward movement, and the flex joints are there to take up whatever movement there is as far as torque. Personally, im not sure why mercedes even decided to add a U-joint to this driveshaft setup since it doesn't really need it, probably just for removal and service actually. If it didn't bend there, it would be a major pain to remove.
These guys would be right if you had a solid rear axle and no slip yoke on the tranny to make up for suspension movement, but since you have an independent rear suspension, fixed diff, and flange attachments, as well as a well proven setup thats on hundreds of different cars for the last 50 years, you are assuming no additional risk.
Just think about how most of these trannys and diffs easily go for 200,000 to 300,000 miles without any issue. I replaced the diff in my old 83 300D at 340,000 miles to change the ratio, and it was still in great shape.
RE: Drive Shaft Repairs & Updates - winmutt - 08-01-2011
There is an angle of deflection on that U joint. It bends under stop start pressure particularly.
I was under the impression some special tools were needed to get the flange of the trans.
RE: Drive Shaft Repairs & Updates - Greazzer - 08-01-2011
No special tool to get the output flange off at all. It just slides off and on.
You do need a special socket I was told for that weirdo looking nut. You can use a 30 mm deepwell OR channel locks, and then the old screw driver chisel trick with some locktite.