Questions and Answers

Cadillac Seville Stuck In First Gear Q. Vincent, I have a 1976 Cadillac Seville, and the auto transmission stays in FIRST gear. You can't manually nor automatically get it to shift to SECOND or THIRD. It goes in REVERSE and FIRST gear just fine. It is a 350 cid EFI engine with 74,000 actual miles. It has been set-up for about a year.

The engine has two leaking, externally, injectors. This causes the engine to run a little rough at low rpm mostly. It has all power and A/C. Any suggestions would be appreciated.

Sincerely,
Terry

A. I would guess, based on the fact it sat for so long, that the vacuum modulator or throttle valve in the transmission valve body is stuck. I would pull the vacuum line off the transmission modulator and see if transmission fluid comes out. If it does, replace it.

Using a hand vacuum pump, apply vacuum to the modulator and make sure it maintains a vacuum. If not, replace it. If that checks out okay, then we probably have a valve body problem.

At this point all you can do is drain the transmission fluid and replace the filter. Fill it up with fresh fluid and drive it. Hopefully the fresh fluid will get the valves in the valve body moving again.