pipefitter

My all stock '96 has a new issue. My truck's trans seems to have a lock/unlock issue around 45-55 mph. Driving between 45 and 55 mph, barely touching the throttle, and it will shift back and forth, like the converter has lost it's mind. I looked up the issue, and someone said Geno's Garage made a "filter" that will stop the electrical problem that causes this problem. Any ideas? The truck has 128,000 miles now, and was rebuilt with about 60,000 miles on it.

Lary Ellis (Top)

My 96 did the same thing it was the TPS.

patdaly

Yep, TPS, could also be the pivot bushings worn at the TPS, can be noise from the Alternator, lots of different possibilities.

Start fixing one thing at a time.

pipefitter

A friend scanned the TPS. It started around .089 and was 3.0 @ wot. Is that low? I also read where it could be a bad ground on the passenger side battery. Has anyone heard this?

pipefitter

I replaced the TPS yesterday, and the problem is gone. We scanned it again, and at wot, it was around 4.25, or so. Much improved shifting.

unioncreek

I would replace my TPS every years for about three years. Finally got tired of paying the price for them and got rid of it. Put a potentiometer in. The only thing I didn't like about it was the TC didn't unlock until you got below 45. Put a TC lockup switch in to unlock it. Works good now.

Bob

pipefitter

Thanks. This is the first time this truck has it replaced, but I should have changed it about 4 years ago. How difficult was your swap?

joem

my 1995 started quickly unlocking and re-locking right after I put in a Napa alternator. Is there any sort of suppressor I can add to fix the alternator noise? Sometimes it wont do it at all, others happens so much I have to ride the brakes to keep it unlocked