I just changed the filter on the Porsche Cayenne that my daughter drives. It has a very slow leak that appears to be at the input shaft seal. At 180K + miles on the car, I don't think its worth the cost and trouble to replace the seal. I'm thinking either:
Leave it alone and watch to see if it gets worse - it's been wet there for 5 years, but doesn't drip regularly.
Use some sort of 'Stop Leak' additive.
It ran and drove well until the fluid started getting low recently then started shifting hard once it warmed up (and fluid ran through the cooler). The fluid, pan, and filter looked great. I'm more concerned that an additive may mess things up worse than just leaving it alone.
It's an Aisin 6-speed transmission. What does GRM say?
Keep it topped off. Until you can't keep fluid in it.
FMB42
New Reader
3/4/21 3:30 p.m.
I'm with Ranger on this. Stop leak AFT, or additives, can help a bit, or they can quickly send you to a transmission shop. In your case I'd search the Por forums for what, if any, stop leak fluid/additives they recommend/have experience with. Checking the level, as per the owner's manual, twice a month might be your best option.
Leave it alone.
After what happened with my Volvo, I would replace the entire pump, not just the seal. (The torque converter bushing spun in the pump. Then it walked out, ground up the seal, and my car went from awesome to Dexron fountain VERY quickly. Trans guy said Aisins sometimes just do that. Comforting)
FMB42
New Reader
3/4/21 5:44 p.m.
Never a boring moment in the GRM forums.
Pete. (l33t FS) said:
Leave it alone.
After what happened with my Volvo, I would replace the entire pump, not just the seal. (The torque converter bushing spun in the pump. Then it walked out, ground up the seal, and my car went from awesome to Dexron fountain VERY quickly. Trans guy said Aisins sometimes just do that. Comforting)
This is exactly what the transmission in the XJ did. Drip, drip, followed by a stream. Aisin pumps are apparently known for this.
When Ranger50 said it, I believed it. Filled the fluid at 40 degrees C (Garage Alexa converted to 104 F) transmission temp and torqued the fill plug to 25 ft lb. Done.
It's been road tested and dropped off with AAZCD kid#3. If it does the Dexron (actually Mobil ATF 3309) Fountain, then we will pull the 4.8L V8 and figure out what we can fit it in. 
In reply to AAZCD (Forum Supporter) :
Yeah,yeah, 3309.
My trans guy self-warrantied all of his work, had to stick do doing bench jobs only because of how busy he is, has an incredible warranty record (like 2 comebacks in five years), and everything that isn't a CVT gets Dexron VI.
Good enough for him is good enough for me 
He did my trans about 45k ago.
Hmm, probably should do a trans service.
