Brian Felts

Hey all got an odd question for you. I had changed my tranny fluid in my 84 Auto a few weeks ago and all was good and sealed up. Some time this week the pan gasket just started a steady drip out of nowhere. The bolts are torqued correctly still.......What would cause this? Any ideas before I change it so it does not happen again.


Brian

Tails

Brian,
Is your transmission a 4 speed/6 Bolt/Large Case modle 722.3 series Mecedes Benz (A28 PorscheType AT), if so did you replace the pan gasket with a part no 126 271 10 80. If yes then you have fitted the old type pan gasket which was replaced in 1994 by pan gasket 126 271 11 80.

Complaints were:
Transmsiion fluid leakage due to gasket tearing or splitting along the side lengths, or rollin inwards at the forward corners.
This complaint can typically occur approximately one week after transmission servicing at the 30k or 60k service.

I purchased a auto transmission kit from my OPC "packed in 2002" and it contained the old gasket and it leaked within a week (split along side lengths). I obtained a new gasket 126 271 11 80 which is a more substantial gasket, installed and no porblems since. I posted an "Alert" on this 928 forum with photographs.

Tails 1990 928 S4 Auto

Brian Felts

How do I tell if the kits carried at my local parts store have the new gasket or the old gasket. That sure seems like exactly what happened to my gasket, have not taken it apart yet but it is coming out of the side.


Brian

borland

There's no reason to torque the bolts. You only need to tighten them until the pan tabs bottom out on the transmission body. They won't work loose.

Not everyone replaces the gasket with a Porsche or Mercedes gasket. Most use aftermarket gaskets from various German manufacturers. They should be fine.

I suggest you try another manufacturer this time and inspect the pan for warping from being overtightening by a previous installation.

the flyin' scotsman

The torque is quite light...........8 Nm.

Did you X cross the tightening sequence to avoid warping the pan?

G Man

I recently replaced the pan gasket in my 84' with the updated part. I got it at the local Mercedes dealer for around $11.00. I still had a leak from my trans. Turned out to be the O ring seal that fits around the trans modulator. $2.50 from the Merc dealer for that one.

Brian Felts

If the pan bolts are only 8nm I may have slilghtly overtightened it but not buy much. Yeah I always use an x pattern just out of habit on everything. I am leaning to the updated gasket......because it is clearly leaking out the seam from the gasket to the pan.


Brian

928ntslow

The way I always do the tranny pan is to slightly tighten, then check at a later time. If it leaks, tighten a tad more and wait a day or so and check again. Repeat this process until it stops leaking. Its the only way I have ever gotten the tranny to be leak free at the pan gasket. You CANNOT tighten very much on the first go around. The tranny has to go through heat cycling's between tightenings. Its a finessing procedure of sorts.

Brian Felts

You know I am going to go with that recomendation on tighting over time. I have never had this problem on any American or German car but as I have learned many times 928's break all of the rules I have ever known.


Brian

Brian Felts

Just ordered the updated part number gasket.......Thank you so much for all of the help. I got the gasket taken off that came with the kit and GUESS WHAT!! Yep it was split right down the side as stated above!!!


Thanks again
Brian