Re: leaking th400
 

thankyou everyone for your help! ive have the fluid level to the dipstick full mark, WITH the deep pan on...did not remark the full mark...2 3/4" deep pan.

Re: leaking th400
 

Fluid level cold should be at “add 1 pint” ATF will expand as it heats up.

Re: leaking th400
 

1 1/2" ...full mark to dipstick end.

Re: leaking th400
 

Are you using the oem dipstick and tube or an aftermarket ? Even with a deep pan I believe the fluid level should be below the pan rail. If it’s an aftermarket dipstick try draining the pan so the oil level shows about 1/4 up the dipstick cold. Then go for a test drive heat cycle the trans and recheck to see if the oil level is at full when hot.

Re: leaking th400
 

we originally had a fancy milodon unit. i thought it was the leak source, went back to the factory piece. will get it sorted out and go back to fancy...

Re: leaking th400
 

You just need Flex Seal

Re: leaking th400
 

pan manufacturer says fill to the factory full mark...WTF... the flex seal idea is sounding better adger...

Re: leaking th400
 

Before you start throwing parts at the transmission you really need to locate the source of the leak. My days as a GM tech when I had a complaint of a transmission leak, I cleaned the entire surface areas with brake clean and then used air to make sure it was completely dry. Next I used spray tracing powder and sprayed the entire area., in a short time you should be able to see the powder turning a pinkish color at the source of the leak. It may be as simple as transmission fluid leaking around the front pump cover bolts that would make it look like a pan rail leak.

Re: leaking th400
 

I’d say the manufacturer is wrong. In 40 years as a tech, I’ve never started a trans with the level at the full mark.

Re: leaking th400
 

with the pan off, dipstick in, the full mark is higher than the trans/pan surface. the modulator valve bore is right there too....sure seems to be seeping out there. the valve and o/ring fit feels sloppy. measured it all up and installed theres not much crush on the o/ring, .020" roughly...