Hi. I am new to the forum.
I have an 03 S-type that I have had for many years. 298,000 miles on it. I have done extensive work on it throughout the years to keep it running well.

One thing that is bothering me now is that I have changed the transmission oil and pan and the new pan has started leaking about 1 month after install. I had tightened all the mounting bolts to 10nm in the order spec'd. Since the leak occurred I have given each bolt just one more click tighter and it hasn't resolved the issue. Has anyone else had this problem? It has a rubber gasket so I did'n't use gasket sealer on it....should I have? I cleaned the surface really well. Incidentally it is leaking from the same spot, corner (screw) where the previous pan started leaking from.

FYI, I have checked the sensor plug that is known to be the cause of a trans leak on this transmission and it is dry. I have also checked the fill plug and it is dry as well.

Any insight?

Thank you!

 

You need to clean up the surface really well and get it dry and then drive it just a little bit and look for that first bit of oil and that’s where you’re leaking from. If you wait too long it spreads all over the place and it’s no use for diagnosing the source. once you know the source you can look at it and try to determine the reason why

 

Thanks for your reply! I have done all that already several times. That's how I know what corner/screw it appears to be leaking from.

 

Hi
unless you buy a genuine one, all the copies leak.
are you sure its a ZF Genuine part, lots of clones out there
cheers
Joe

 

+1 to Joe's feedback, must install a genuine ZF genuine pan/filter. A bit more expensive but worth it!

Besides the crap fit (been there, done that) the filter material is inferior and can cause fluid "starvation" issues...

 

The only other possibility that I can think of is the transmission breather/vent. This would imply that it got over-filled. If it was filled to overflowing the fill hole but the transmission was not up to temperature this could be the case.