126 Tranny issue - end of the line?
 

Just blew the rebuilt tranny that was put in two years ago (3700 miles on it). Still trying to get the shop to replace it under warranty, but not making much headway. Looks like the end of the line. Is it worth parting out, selling as-is, or just donating to one of those charities that gives you a tax credit?

Car has 121,000 and is decent, drivable condition. Usual old 126 problems with a/c and power windows, but pretty damn bulletproof. Hate to let the old girl go.

Lots of good used transmissions out there!

With that LOW mileage that car has many more years to go!

What do you mean by "blew"?

Symptoms? Problems? Diagnosis?

The car is a 1985 380SE. The rebuilt tranny cost $2500 in 2010 and the mechanic I use (who didn't do the tranny work) said the transmission is shot. He sent it to a tranny shop the last time, one that he uses because he doesn't do that kind of work. (I've been using this mechanic for 10 years and he's the kind of guy that does little things free of charge or lets me buy my own parts from Peach Parts and he puts them in). The tranny obviously wasn't rebuilt properly in the first place, but it was guaranteed for 12m/12k and it's been two years and 3700 miles. He's fighting with the other shop for them to cover it. The car just stopped with a puddle of fluid under it. Not worth putting another 2500 bucks into her when the a/c doesn't work, windows are intermittent etc.

Depends on whether you want to take the chance again...it is shot and can be repaired but you gotta get it out and then find out what's wrong with it. Most shops will want to just do a rebuild ($$$). They sell rebuilts everywhere.

Hard to give an opinion without opening up the tranny. They could have completely rebuilt it brilliantly, but had the front pump seal fail . Or ,they could have just put it together with spit and gum and figured it would last 2 years. You don't really know unless you watch what they do or DIY.

FYI
 

A good used transmission is $150 - $400 USD on average.

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I don't do my own work, so the part isn't the issue as much as the labor charge. Trying to get the guy to make right on the job. I'd gladly pay that for a used tranny if he'd cover the labor charge.

I would never let them get away with it. Nor would I scrap a car with 121k on it. That is very low miles!

By blew I mean the car just stopped moving forward and just revs in any forward gear. It does engage in reverse.

Oh, so that's probably your notorious B2 piston. Why didn't you say so before? That's a pretty easy fix to do from outside ( if it's the piston, not the band or strut) and cheap. Fix it , or get the shop to do it. Do a search on B2 here or in diesel. But you said puddle of fluid- could still be if coming from the B2 port.

Answer
 

This is a simple repair that many members have done.

Here is your diagnosis:

B2 Piston Failure
B2 Piston Failure - PeachParts Mercedes ShopForum

722.118 transmission B2 servo/piston *B2 Piston*
722.118 transmission B2 servo/piston - PeachParts Mercedes ShopForum

I Am Really Hurt Now *B2 Piston*
I Am Really Hurt Now - PeachParts Mercedes ShopForum

C220 won't go forward. HELP!!! *B2 Piston*
C220 won't go forward. HELP!!! - PeachParts Mercedes ShopForum

B2 Piston W124
B2 Piston W124 - PeachParts Mercedes ShopForum

My Superior Shift Kit thread (W124 300DT)
My Superior Shift Kit thread (W124 300DT) - PeachParts Mercedes ShopForum

Slow leak around B2 Piston--change piston?
http://www.peachparts.com/shopforum/diesel-discussion/307642-slow-leak-around-b2-piston-change-piston.html





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FYI
 

Have your mechanic contact me directly.

All of the issues sound simple.

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Certainly sounds like a B2 failure but odd that there would be a puddle of fluid under it, unless a part of the piston went through the cover or something. Obviously I'm just bench-wrenching here but it could also be one of the hoses failing and then the transmission is starved for fluid and won't go forward (in which case it wouldn't be immediate, but could also ruin the transmission). Might also want to post your location, if there is a willing experienced member nearby perhaps he or she could take a look and give a second opinion. At the end of the day, used transmissions are fairly cheap...certainly worth the expense to keep the car on the road. Labor shouldn't be too bad with it either for a decent mechanic.

If the cover or seal were not installed properly when it was rebuilt it could have blown the seal....