My truck is automatic and when shifting to O/D there is an up shift and down shift three or four times. This also happens when you hold a steady speed of about 50 miles per hour, it kind of searches for a gear.

The dealer replaced the alternator and that helped for a while (not long) and now I'm back with the same problem.

I believe the dealer should be held responsible for fixing the problem since he replaced the alternator, which in his opinion should have corrected the problem.

Any idea's on what could cause the up shift and down shift?

 

Dirty battery terminals or dirty ground at the PCM.

Cleaning the above usually fixes it.

If not, there is a wire you can wrap with tin foil, but I don't know which one, but a search mind find it.


phox

 

I think shielding the OD solenoid wire might help, like Phox said - pretty sure it was OR/BR on my '98...