722.6 issues
722.6 issues
I've driven it for around 1500 miles and other than a slight slip changing from 3rd to 4th drove fine.
I do a fair bit of towing with it 2/3 ton maybe and after driving it last weekend it lost forward drive, still had reverse but no drive, after reversing 4 miles and put it in drive and it drove for 4 miles perfect, but as soon as it was taken out of drive it wouldn't drive again, still had reverse.
Upon draining the oil (only 1500 miles old) it was heavily contaminated with metallic particals more than likely blocking the valve body Hense loss of drive.
After speaking to a local Mercedes auto specialist his diagnosis is that the torque converter broke up creating the contamination.
He informs me that these torque converters are know for this and an uprated one can be supplied, along with a modified vavle body and a rebuilt box, at a cost.
Is this over kill for my use?
I can source and second hand box and t/c quite easily and relatively cheap , but am I looking at another 1500 miles and the same again?
Did I just get unlucky or am asking to much of this box?
Any thoughts
THE DIGGER
08-06-2015, 03:23 PM #1I've a 772.6 that I swapped into a G wagen on 35" tyres with a 606 6mm pump and stock turbo so only around 180 odd hp.
I've driven it for around 1500 miles and other than a slight slip changing from 3rd to 4th drove fine.
I do a fair bit of towing with it 2/3 ton maybe and after driving it last weekend it lost forward drive, still had reverse but no drive, after reversing 4 miles and put it in drive and it drove for 4 miles perfect, but as soon as it was taken out of drive it wouldn't drive again, still had reverse.
Upon draining the oil (only 1500 miles old) it was heavily contaminated with metallic particals more than likely blocking the valve body Hense loss of drive.
After speaking to a local Mercedes auto specialist his diagnosis is that the torque converter broke up creating the contamination.
He informs me that these torque converters are know for this and an uprated one can be supplied, along with a modified vavle body and a rebuilt box, at a cost.
Is this over kill for my use?
I can source and second hand box and t/c quite easily and relatively cheap , but am I looking at another 1500 miles and the same again?
Did I just get unlucky or am asking to much of this box?
Any thoughts
whipplem104
08-06-2015, 03:41 PM #3What tcu are you running. Check your lock up parameters. If you lock up the tq converter to early it will shudder and this will break the converter. You should have no problem doing what you are doing if tuned properly. You also cannot have the converter locked up under heavy load with lots of torque. You will have to take the transmission out and have it at least disassembled and cleaned. It would be nearly impossible to diagnose still in the car as well. It could easily be a clutch in the transmission failed as well.
Also on long hills with a trailer I would have knocked the gealever back into 4 to unlock the t/c to let it Rev higher and keep the egt lower, temp of the box never got higher than 120 c* as I've a big cooler.
I'd agree about not knowing until it's been stripped, but the guy seemed fairly sure as he said the converters are known to be weak?
Also I don't think a modified valve body is needed as I can change the line pressure via the controller, or it that for something else?
I'd agree about doing it once, but the rebuild is €2000 ish, second hand box is €250, I'd swap one in around 3 hours.
THE DIGGER
08-06-2015, 04:06 PM #4Thanks for your replies, running a ole controller, hadn't messed around with the torque converter lock up so only locked over around 50mph in 5th.
Also on long hills with a trailer I would have knocked the gealever back into 4 to unlock the t/c to let it Rev higher and keep the egt lower, temp of the box never got higher than 120 c* as I've a big cooler.
I'd agree about not knowing until it's been stripped, but the guy seemed fairly sure as he said the converters are known to be weak?
Also I don't think a modified valve body is needed as I can change the line pressure via the controller, or it that for something else?
I'd agree about doing it once, but the rebuild is €2000 ish, second hand box is €250, I'd swap one in around 3 hours.
What rpms are you turning at 50-55 mph in 5th gear.
There is no need for any special valve body with the standalone as you can adjust pressures.
As far as the converter being weak. I run 500hp/500tq through a stock c230k converter. It is all about the tune and not asking the trans and converter to do things they should not.
whipplem104
08-06-2015, 07:39 PM #51st off 120c is to hot. I do not know how Ole is doing temperature compensation but shifts will get lazy and slip at those temps under heavy load.
What rpms are you turning at 50-55 mph in 5th gear.
There is no need for any special valve body with the standalone as you can adjust pressures.
As far as the converter being weak. I run 500hp/500tq through a stock c230k converter. It is all about the tune and not asking the trans and converter to do things they should not.
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