blown 87

I did a MB wagon trans last year that came with the trans in the back of it, it was not the transmission (or the right case) for that car, needed a "Married" valve body and TCM that was VIN dependent, and he wanted a break because the trans was out of the car.

And people wonder why I am gruff sometimes.

Rob Edwards

Hell, Greg had me disassemble a G28-03 in about an hour at SF10. I couldn't do it again for $1000 strapped to Erica Campbell's thigh....

Landseer

I prepared to rebuild one and had all parts but clutch steels and frictions stockpiled.
The case was broken, though, from the parking pawl.
It was complicated inside, but I think doable. With great attention.
Did complete prep of the case for welding, but realized it wasn't salvageable with methods I could afford.
All the innards are stored carefully. I'll definitely rebuild one in the next year or so, just to do it.
Got an S4 box of unknown condition instead.
It turned out to be the best shifting one we've got

(My wife and I did a 2 speed buick box once on the dining room table and it worked perfectly.)

Keys seem to be extreme cleaning and very careful attention to parts fit and sequence of assy.

jcb928

I just had the trans rebuilt in my Mercedes 420sel and in the future I will just buy the best used transmission I can find.

danglerb

Unless some model of car/transmission his a known history of problems, one out of a recent known running wreck with some new seals etc. is the way I would go too, "unless" I had some serious performance plans and that kind of begs the question of why own a Porsche?

Black Sea RD

Understood.

However the whole reason I was watching over his shoulder and at times assisting with the rebuild under his tutelage, was to learn as much as I could about the mysteries of the 928 Mercedes sourced auto transmissions. He took his time to explain the rebuild steps carefully to me. This was in further research into other possible TBF causes.

I will add that if it were up to me I would get one from a reputable rebuilder with a warranty.

Cheers,

Mike LaBranche

Before the professional specialists were just that, they were idiots just like the rest of us. Training, experience, documentation, tools, parts... makes a specialist out of anyone interested enough to become one.

Your risk is the value of the trans as a core for a rebuilt unit. You can pick up used trannies all day for a grand, rebuilt for 2. Each trans is no doubt a story all it's own wrt what they need for a rebuild, I'd dive in and take a look. Good luck, have fun.

danglerb

I'd say the risk is that the transmission at some later time fails in a destructive catastrophic way at the worst moment. Working isn't a good indicator that its fixed properly or reliably. A missing or improperly installed washer, C clip, you name it, and it may work fine for some period of time, then WHAM.

dr bob

"WHAM" is a lot like "booing-clatter", with a higher grade for level-of-effort.

Too many of these cars suffer from half-fast efforts at repair or servic, literally time-bombs waiting to be triggered by some unsuspecting owner or purchaser. Ever wonder why some cars show up on the market with "ran great when I parked it, it just needs a xxxx"? Disabling that xxxx on purpose or by accident masks all the other XXXX and NNNN problems that were caused by just-make-it-run! fixes orderd by desperate owners.

A dozen or so years ago, a good neighbor asked me to look at a friend's Jaguar that was flashing a check-engine light and was running poorly. Code reader saod one of the two throttle-position sensors had failed. So he took the car back to the guy who serviced the car for him at the local gas station. Too expensive! Isn't there something that could be done, just enough to get the light to go out so I can sell it? So the gas station hack jury-rigs something to fool the controller, and the light goes out. A week later some other things are causing the light to go on. Bob, would you like to own the car? Sure, I'll give you $500 for it. But the market is $15k!!! That's for a car with traceable regular competent service in good mechanical and cosmetic condition. Bottom line is that there are plenty of time-bombs around, owned by folks who decided that their expensive car wouldn't be so expensive if the guy at the Arco station took care of it rather than a paying a competent place to do the work. Will a DIY "rebuilt" auto trans improve the value of a car? There's a slim chance, if the DIY'er happens to be a Greg B or Greg N, some known quantity. That's a really short list. For the rest, getting a good rebuild is an investment in your won enjoyment of the car, as well as in the future resale value.

Landseer

Dr. Bob,
I think you could rebuild an S4 transmission and trust the repair.
So do you, right?

yardpro

i totally agree with this..
i rebuilt a chrysler 727 transmission in a full sized 83 cherokee i had years back in college....worked fine for a while then one day.... BAM.... it threw the governor pin through the case.... the trans was shot..

soupcan

Automatic Transmission/Transaxle
Transaxle Assembly
Without Locking Differential 96030000412 $8638.65
With Locking Differential 96030001412 $15878.06
Contact dealer for most current part and price information.

MattCarp

If you do decide to do it, you've got to completely document it for us! In that way you may even be able to invite some sponsors!!

mpesik

I did it. Auto 1988.
I didn't know much more than the average guy.
I spent 2 weeks, reading everything I could on that transmission.
I took it all out and partially disected the vehicle.
I brought the whole tranny with me downstairs and opened it up.
I rebuilt that -exotic mercedes tranny myself.

If I can you can as well. It takes a little passion .
One mistake I did was using the same rubber O ring and slightly pinching it. So the tranny ended up with a slight leak.

I replaced it with a Viton -O- ring and everything was peachy.

fbarnhill

Well, after reading all the other posts, looks like the MB auto is way more complicated then the Torque flight 727 we used to rebuild over night and hit the drag strip the next day. Never once did one go boom. Hell, that was 30 years ago and has no relevance to these modern transmissions.
That being said, I will have to throw my advice into listening to these folk on this list who have been there done that with these very transmissions and suggest getting a good rebuilt unit from a known source.
However, make sure you know your source. Just 5 years ago I bought a rebuilt 4spd auto for my BMW 525 and it leaked from the 1st day. Also those transmissions are so precious to BMW that they don't even allow you to add or check the fluid without pulling the pan. Well this one was from a good reputable rebuild’er in Atlanta and everyone on the internet raved about them. They wouldn't even answer the phone or call me back when I called to get them to honor the warranty. My mechanic at the time just pulled it back out and replaced the pump seal himself. Yes it had a warranty but if they won't honor it what good are they? I just wrote it off as an expensive learning experience.

You will be able to enjoy your car a lot more if you know you can trust it. And there are times where that trust is worth a few extra $$$.

Best of luck,