I just rebuilt the th400 in my car and im having an issue with low line pressure. The trans is fully automatic with a stock blue regulator spring and 2 horseshoe shims. I test drove after rebuild and everything seems to function fine but the shifts seemed soft so I checked line pressure and didnt like what I seen.
park 70
reverse 70
neutral 70
drive 70
L2 70
L1 70
I disconnected the vacuum modulator and retested with same results except: L1 120 with shakey needle??
I test drove with gauge in the car ALL readings stayed at 70 at all throttle positions. Trans doesnt slip?
I tried another pressure gauge same results.
Before I pull the pan down anyone have any ideas on what I messed up?
Im thinking vb gasket? pr booster valve in backwards?
Thanks Mike.
park 70
reverse 70
neutral 70
drive 70
L2 70
L1 70
I disconnected the vacuum modulator and retested with same results except: L1 120 with shakey needle??
I test drove with gauge in the car ALL readings stayed at 70 at all throttle positions. Trans doesnt slip?
I tried another pressure gauge same results.
Before I pull the pan down anyone have any ideas on what I messed up?
Im thinking vb gasket? pr booster valve in backwards?
Thanks Mike.
