jimmy gmc transmission?
- Thread starter Jean
- Start date
Molson02536
New member
How do you know it's going out??? It may be as simple as a few parts then needs to be replaced to keep your transmission running 100%.
Put a line pressure gauge (or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.490" boost valve (easy fix in pan).
If your have Soft shifting, gradual performance degradation: Poor line pressure rise due to leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or worst case: leaky seals throughout. Transgo HD2-C kit fixes first two without removing trans. Seal restorer may fix last problem, but probably R&R. Also try a transmission flush with BG brand products (Firestone stocks it).
Good luck and post me back why you think your transmission is on it's way out, I had a guy offered me his Blazer a few month's ago for transmission problem for $500.00. Got the blazer and when through it and found a bad wire connection at the transmission, cleaned it up and everything works great and all the line pressure is where it should be. Now i have a summer project with my son, so before you go off replacing the whole transmission. Check to see if it's as simple as replacing the Boost valve ($45.00) of it may even be a faulty TPS. ($65.00)
Keep me posted and don't forget to replace the transmission mount too with the motor mounts.
