What trans fluid in a TH350C?

[olds307 and 403]

I am pretty tired of these old GM transmissions leaking, despite replacing seals and bushings. I have used dino Dexron 3 and Type F, didn't matter, leaked somewhere. I see a lot of racers use tractor trans hydraulic fluid, looks like about a 10W30 weight for the stuff I plan on using. One guy is in the low 12's running it. I will be using the lock up torque converter an will add a Transgo shift kit in the fall.

 

[Ribbedroof]

I've always had good luck with Dex III, but the one in the wagon is a leaker for sure.

Lots of times they leak at the speedo adapter, most people don't replace the seal in the adapter, just the O ring...hell, most people don't even know there IS a seal in it

 

[olds307 and 403]

I've always had good luck with Dex III, but the one in the wagon is a leaker for sure.

Lots of times they leak at the speedo adapter, most people don't replace the seal in the adapter, just the O ring...hell, most people don't even know there IS a seal in it

I sealed it with Ultrablack, yeah those speedos always leak. I am still leaning to the trans/hydraulic fluid.

 

[Wageslave]

I know some people use HyTrans hydraulic fluid as it is less slippery and will cause worn clutches and bands to grab better, but can make an otherwise good shifting transmission a little harsher shifting.

 

[olds307 and 403]

I know some people use HyTrans hydraulic fluid as it is less slippery and will cause worn clutches and bands to grab better, but can make an otherwise good shifting transmission a little harsher shifting.

I am OK with firmer shifting. I will run 2 quarts of Type F for colour and use the nylon filter as the Dacron filter can starve the trans with thicker fluid. It seems to me the Dacron filter interferes with the lock up solenoid since it is larger.