1991 300te 4matic.

While pulling away from the curb it revved up to about 5000rpm still going about 15mph. It has also suddenly revved up while driving down the road. Car has 200k(ish), trans has about 95k.

Seems like it is slipping but it is at odd times, anything particular to look at? Trans was drained and refilled (new filter) with Fuchs full synthetic in September of last year, fluid levels are good.

First things first,

it seems it is the norm for people to contest the gear engaging RPM when a transmission does not shift properly. If it did slipped then it slipped, but do not force it...I did not do that the first time it happened to me?

This is my opinion...remember any synthetic oil is not as viscus(thick) as the Dinosaur Oil, and your transmission is not a "Intelligent one"(722.9 & 722.6). The oil specified for that tranny you have took Dexron II which was more than addiquit, but Dexron II is non existent on the planet, so Dexron III or any brand is far more than addiquit..On my 722.3-722.5's I use Dexron III from WallyWorld in the blue jug...Way more than addiquit.. I would not be using all this wiz-bang oil on the transmission as it is just to thin to seal in the bores of the valve body(which is where I think your problem is at), and the sealing is not there for the clutch pack either.. Yes the wiz-bang oil has better thermal properties, but these trannies never really came having such stuff-They were on DexronII..

I would do a fluid exchange to get that stuff out as the tranny is too new.. Here is how I do the fluid exchange on a W210, but the concept is the same for every car-See post 11:

Will Vin# reveal Torque Converter Drain Plug - Mercedes-Benz Forum

Martin

So your opinion is that Fuchs synthetic ATFIIE is not the correct fluid? The owners manual, dealer and this web site suggest it.

Also, it is not my car; I'm passing on second hand info to try to get some ideas on what might be happening.

I'm just going what is documented in the user's manual, and here is the manual to the last all hydraulic transmission(722.5) before the 722.6. It is black and white in my eyes. This to my S320..

Mine says Dexron II?

Martin

Attached Files

1996 S320.pdf (107.7 KB, 79 views)