How the heck can I get this trans to quit leaking from around the detent cable? I've tried it dry. I've tried RTV. When I cracked the last one from overtightening and removed it I noticed that it looks as though the top of the gasket is not being pulled down by the cable foot as good as the bottom (next to the hold down bolt). Is it these crappy made in China cables that I've been getting from Advance? The one from NAPA didn't really look any better. I might try making a V-shaped hold down brace that would put more pressure more evenly on the foot, but I wanted to see if you guys had any tricks/tips first... I can't be the first with this problem. Thanks, Harry

Try replacing the multi-lip seal. See your local GM dealer & ask for pn 1262475.

Where is the seal that you suggested located? I searched GMpartsdirect but they didn't have the usual exploded view of the part and location. I will tell you this, I did end up making the V-shaped hold down bracket and, with a good dose of High Temp RTV, it hasn't leaked in 5 days now. I honestly think it was the crappy cable from Advance. When I finished my bracket and held it up to the cable foot you could see where the plastic had actually bent because it's not strong enough to put equal pressure on all sides of the seal. Just a heads up before anyone else buys a Made In China TH350 detent cable from Advance.

Check your vent tube, i had the same problem on my friends TH350, it also took fluid really slow when you would fill it. I blew the vent tube out and it was fine.

Hope this helps.
Jason