BJAFARI93

Well today a coworker (has the exact car as me down to the miles, year, colors, packages, everything 1997 e420 sport) told me his car was making noise. I took it for a ride and it seemed the rear end was making the noise. After taking it to a mechanic and leaving it with him he said it was the tranny and that it would only make noise when cold but was fine once warmed up. Have you guys ever heard of something like this or had this problem. Kind of an expensive fix specially if it could be something else. The trans in these cars are 722.625.

Thanks

TMAllison

What did the mech recommend needed fixing?

The trans ought to have codes or out of range adaptation values that would tell/show what the problem is.

There are countless things from the back of the trans to the rear wheels that can make noise.

BJAFARI93

The trans wouldnt throw any codes, it just made a grinding noise, took it to two mechanics and they both said it was the trans. I sat in the car today and put it in reverse gave it a little gas and it moved forward as if it was in drive. I'm not sure to be honest with you i was just trieing to help a coworker out.

TMAllison

You need to go to a {better} shop, one that has the equipment capable of scanning it.

I'd flat bed it there as 722.6's are easily chewed up. Dealer R&R is ~$6k. An independent rebuilt and replacement should run ~$3000.

ohlord

do throw codes.You need to get it on a lift and isolate if it is the rear diff making the noise or if it is the trans.Or per TM several other items from bearings to brakes.
Where are you located?

BJAFARI93

Im in Mass and the trans is in a 97 E420 722.625. I looked the car over and there werent any codes that popped up (on the dash) but maybe there is a computer that stores them elsewhere? Im not sure anything you guys can remember would be great.

TMAllison

Trans codes are viewed by MB's SDS laptops or similar quality scanners; as are adaptation values which are equally important as they tell how the trans has been adjusting itself internally recently. Most Indies dont have those scanners or ability to understand the adaptation data unless its a very large shop that typically works only on newer MB's who can justify the expenditure.

Tell your friend to go to the dealer to find out if its repairable or toast. Would also be helpful to know if that dealer actually repairs/rebuilds trans or uses rebuilts for everything other than valve body problems. Some dealers do rebuild; most don't in my expirience.

ohlord

codes can show up as pending codes even on 60 buck obd2 testers.P0700-p0800 range codes.Turbine sensors,clutch pressures,trans modules,etc. sometimes they don't show up as an active check engine light but they may be stored as pending in the ecu history.
ohlord

TMAllison

You are correct of course. I've rarely seen anything ohter than Po715 and Po750 range codes read via OBDII. Don't think I've ever seen anyone post concerning a PO800 series code.

Regardless, with many trans problems you can "fix" the underlying issue or throw a rebuilt in and then clear those codes using OBDII til the cows come home; until SDS clears them the underlying problem will oftentimes remains and the trans won't work.

As much as people dont want to go that route, IMO the dealer is best equiped to diagnose trans problems generally. The adaptation values are equally as important as the codes themselves as is the training of the tech who interperts. Most Indies and AMCCO or the like cant pull the necessary data up.