Skunkworks

Definitely need some help here... My 82 US with Auto was driving down the road nice as can be and then the tach suddenly went up to 4k and no more transmission. I immediately pulled over and had the car brought home. I checked the transmission fluid and the sight glass is completely full -- to the top -- way above the full mark! This transmission level had been fine just a couple weeks ago when last checked. Could the transmission line be clogged or something? Any help is greatly appreciated.

Thanks,

David
82 928 US Auto

Podguy

David,

The first thing you need to do is check to see if the transmission is still connected to the car. There is an inspection grid on the front of the transmission. Start the engine and look to see if the torque converter is still spinning. You can check this in park. If it is spinning then you need to make sure is is engaging when you put it in gear. It would be highly unusual for a transmission to just die in this fashion. Then again it would be highly unusual for the torque shaft to break without a bit of noise. It is possible that one of the splined connectors stripped and the engine is no long turning the transmission.

The excess fluid is suspicious. The only way for the fluid level to rise is if the differential oil is leaking into the transmission.

There is a possibility the torque converter failed. They can be removed with the transmission in the car and can be rebuild for a little over $100. After that is is pumps and clutches and things get complicated. While we are lucky that Porsche decided to use a common Mercedes transmission these cars are getting older and the parts harder to get.

One other thing you might consider is the axles. A CV joint can strip and the car with a LSD is stuck just as if the transmission went out.

Good luck.

Either way I have all the parts for a three speed transmission including a good transmission.

brutus

"...The excess fluid is suspicious. The only way for the fluid level to rise is if the differential oil is leaking into the transmission. ....."
Or the trans oil cooler in the radiator leaked and has filled the trans with coolant . Would also show trans fluid in the cooling system at times.

Hilton

In some model years, the fluid level can also rise due to failure of the in-radiator trans cooler.. where coolant enters the transmission.

A local friend had it happen to his '83 928S.

Lizard928

Could be a pump failure,
Do you have reverse?

The extra fluid could be coolant from a popped heat exchanger......

Mrmerlin

or the drive shaft has snapped and the trans isnt turning
thus neither is the front pump so all the fluid will drain into the pan and fill the reservoir to above full.
Based on your info I would say the drive shaft has snapped

Skunkworks

1982 928 US Auto

OK. I put the car up on jackstands and started it. The torque converter turned fine. Put the car in drive and the torque converter kept turning but the wheels did not spin (the fluid has remained at the top of the sight glass (above the full mark).

I drained the transmission and the fluid did not smell burnt. In fact the fluid looked very good. I disconnected the lines to the in-radiator trans cooler and the fluid once again looked good and did not smell burnt. I blew out the lines with compressed air and there was no obstruction. Drained the torque converter and the fluid, once again, looked good and did not smell burnt. I am sure that there is no leakage into the transmission from the radiator (I had this happen previously -- 10 years ago) and all the fluid has looked good. I also checked the differential fluid level and it was fine with no traces of any transmission fluid.

I'll drop the pan next.

In the meantime any suggestions?

Thanks,

David
82 928 US Auto

Skunkworks

I do not have drive or reverse.

What is a "popped heat exhcanger"?

thanks,

David

Speedtoys

The tranny oil cooler inside your radiator.

If that now leaks..you have water in your tranny, and tranny oil in your AF...etc.

namasgt

The torque converter drives the oil pump.... Once you start the car the fluid level in the reservoir should slightly drop. When you shut off the car, it will go up all the way to the top.... Is your cable from the shifter still connected to the arm sticking out of the box on the drivers side?


Ali

Skunkworks

Just dropped the transmission pan. The last bit of fluid looked good. Only thing that implied wear was the extremely small "flakes" (like what is put in auto paint for shimmer).

Any and all advice is appreciated.

David
82 928 US Auto

Skunkworks

The shifter cable is attached and functioning properly.

David
82 928 US Auto

Mrmerlin

if the torque converter is turning with the engine then you have internal transmission damage,
and you will be dropping the trans to investigate further,
maybe the front pump splines have sheared off these are turned via the torque converter

Speedtoys

So..at this point, $1500 has a working used one from 928intl..

Podguy

David,

From what you found it certainly sounds like something internal to your transmission. I am betting on stripped splines somewhere. If you hard internal parts damage then you either need a core or in the case of just age toss the trans.

I do have a good used 3 speed that came out of a Euro S car. Not sure because of the extra horsepower if they are any stronger than other three speeds. I also have a complete five speed conversion. Probably for the price of a three speed rebuild you can convert to a five speed. I also have a core three speed if you need hard parts.