Bill Ball

Thank you, Greg. Oh, slide hammer! Yes, I think I'll go out an pop that pump off now. The guy came highly recommended, had all the credentials as a Mercedes mechanic, but I think whatever good luck he had rebuilding Mercedes/928 transmissions previously failed him this time.

GregBBRD

Depends on what you find and the path of the debris.

Obviously, anything that the pump sucks up is filtered.

If the problem is after the pump (which it appears to be) and before the cooler (you will need to determine) you will need to clean out the lines and the cooler. I'd think that back flushing the cooler and the lines would probably be enough, as this failure looks fairly limited, in scope.

I am interested why the convertor could get installed so far as to rub on the front pump....that line around the "middle" of the convertor is very strange. The convertor "floats" in the oil pump...the drive lugs on the oil pump do not limit the travel. The distance that the convertor is "pushed" into the transmission should be determined by the rear flex plate. The flex plate depth/dimension is controlled by the circlip at the very "front" of the flexplate (right against the front flexplate bearing) which limits the flexplate from traveling to the rear.

Is that circlip present and sitting in its groove?

If that circlip is present and in the groove, the only thing that would allow the convertor to travel towards the rear of the vehicle would be for the rear flexplate to "bow"...which is not common.

GregBBRD

Mechanics are only human and anyone can have a bad day.

People die from mistakes made at hospitals, every single day.

The measure of a good mechanic is what he does to fix the problem.

I assume that he has offered to fix the problem and all you need to do is take it back to him?

Mrmerlin

as far as the front pump gasket goes its best to wipe it off then put the pump back on,
no extra sealant as one side of the this gasket is firmly adhered to the trans main body,
if the gasket is wiped off then it should not leak.
A simple back flush with brake cleaner and compressed air will work,
drain the fluid into a clear container to verify that the fluid rinse is clean.
I am betting since it hasnt run long there wont be much if any contamination.

The converter may have been turned while on the bench and if this was done then it may have been rubbing before the flexplate was fitted,
you can also drain the oil from the TC and look for metal particles.

Bill Ball

He has offered to fix it. Considering time and gas money to get it to him, I was thinking of just doing it myself if it just involved replacing the pump and converter. I can get good donor parts, I believe gratis, so that gets him considerably off the hook.

Speedtoys

If anything else is wrong after that..you'll own the whole stack of parts if you do this on your own.

Bill Ball

OK, I got the pump off. No more metal pieces inside that I could see.

One concern is that every part inside has an 89MY part number (there were changes between 88 and 89), except for the one he changed - the B3 piston. He used 88MY. He doesn't have access to PET, so he went off Mercedes 722 parts sheets. Perhaps that is of no consequence, but I just don't know.

Here's some pics. I think the rear bushing on the primary pump (pic 3) is burned too.

Bill Ball

Well, there was no goop on the primary pump gasket after all. It sure was stuck, so I suspected goop. When I took off my original untouched pump, it came away rather easily and the gasket remained adhered to the primary pump. [Actually the gasket broke.]

Stan, I think you're on to something regarding the two score lines on the TC. Greg, the rear flexplate is fine and the circlip is inplace. I was not aware that the flexplate held the TC away from the pump, floating as you say. Makes perfect sense. I will be sure not to turn the TC in the pump until the cover is all buttoned down.

I now recall that my donor tranny does not have a torque converter. I guess that means that I need to take the tranny back to the rebuilder and let him deal with that. Used ones are available for $500 at 928Intl at "regular" prices. [EDIT: George Suennen has the donor tranny. Turns out it does have a TC and the primary pump I need. If so, I'm going to remove those parts, inspect them and reassemble if they are good.]

Mrmerlin

the clutches seem to not be lining up did you notice that? picture 5

at some point before the flex plate is added the TC will have to be spun to verify that its seated

Bill Ball

Hi Stan:

I thought you only spun the TC until it engages the pump drive. Regardless I gather those scores are not consequential unless they happen from a bad cover assembly.

Yes, I saw that the discs didn't line up. Aren't they free to move once the B3 piston is removed? I'll make sure they are aligned before trying to reinstall if I end up doing the reassembly.

Ducman82

looking at the pictures makes me realize that automatics work on magic and pixie dust...

Bill Ball

Jeff:

Thank you for your suggestion. How's your "new" tranny?

Bill Ball

Yes, I know exactly what you mean. The last great mystery of life.

Bill Ball

Thanks, Dave. I sure felt like that earlier today, but I've calmed down, well, just a bit. I'll keep it in mind if things go further South.

jheis

Yeah, I did a complete mechanical rebuild of a Borg Warner T35 for my 1970 Rover 3500S and I still have no clue how they (automatics) work!

James