74Corvette
Member
Hi, after reading all the recommendations and info on this site I decided to put in an aux transmission cooler. I decided to install the cooler in series after the stock radiator cooler to help with warming up the trans on the colder days. I followed the recommendations here and used AN 8 and replaced all my stock hard lines. Too be safe I also decided to tee in a pressure gauge on the oil cooler feed line (bottom line) as close to the trany as I could get. What is considered the normal operating pressure range for a TH400 oil cooler lines? I am concern as I have read about TH400’s blowing thrust bearings when the pressures in the T/C are too high. I understand that the oil cooler pressure can be an indicator of the T/C pressure as directly measuring the T/C pressure is difficult.
I am seeing 75psi in park/neutral/drive when cold.
40-50psi in park/neutral/drive when hot, (approximately 180F oil temp)
80psi in LO 1 & LO 2 when hot, (approximately 180F oil temp)
Can get to 100psi in reverse if I hold the brake and rev the engine to stall speed.
I also measured the trany main line pressure and they seem good to me. What I get is 185psi in LO 1 & LO 2. Typically sits at 80psi in drive cruising in 3rd.
After this I was concerned the aux cooler was the problem so I unhooked it and just used the stock rad cooler. Pressures did not change.
Does anyone know what is considered normal and what the maximum cooler line pressure is before thrust bearing issue could occur? I have a small block 350 in front of trans. Approx. 2700-2800 stall.
I am seeing 75psi in park/neutral/drive when cold.
40-50psi in park/neutral/drive when hot, (approximately 180F oil temp)
80psi in LO 1 & LO 2 when hot, (approximately 180F oil temp)
Can get to 100psi in reverse if I hold the brake and rev the engine to stall speed.
I also measured the trany main line pressure and they seem good to me. What I get is 185psi in LO 1 & LO 2. Typically sits at 80psi in drive cruising in 3rd.
After this I was concerned the aux cooler was the problem so I unhooked it and just used the stock rad cooler. Pressures did not change.
Does anyone know what is considered normal and what the maximum cooler line pressure is before thrust bearing issue could occur? I have a small block 350 in front of trans. Approx. 2700-2800 stall.