1996 chevy 4x4 dump with plow not shifting


Junior Member
western pa
I have a 1996 chevy one ton dump with an automatic transmission. It started about a month ago to not shift out of second gear. I've checked the tranny fluid, and it is not discolored. It doesn't do it all the time, but when it does the rpm's go up to almost 4000 rpm's. It is still pushing the truck and it isn't slipping. Any suggestions?

John DiMartino

PlowSite.com Veteran
The trans is going into default mode,you might have a bad electrical connection,or a soleniod/switch,sensor problem in the tranny.You need to takeit to the dealer,or a good trans shop.My dad;s 94 did the same thing intermittently for 3 yrs,they never could find what was wrong with it.


one of the first things to do if you have not already is change the luid and filter a cloged filter can do the same thing although it usually happens in all gears otherwise I agree it is likely in limp mode
have you tried shifting manually starting in 1 2 3 d D?


Junior Member
Cleveland, OH
Corroded positive battery terminal can cause this. The connection prohibits enough current for the 4L80E solenoids to shift properly.

Big problem on side-terminal batteries, and if it has leaked acid the cables will be bad too. Acid wicks into the cables inside the insulation.


Junior Member
the wifes 95 GMC 2500 van done this. it was also intermittent. after in and out of the dealer and 250 bucks later, i took it to a tranny shop who checked out the tranny and said nuthing wrong, noone could figure it out but they said it was probably in the wiring from the speed sensor to the speedo or from the speedo to the puter. i actually discovered it in about 20 mins of snooping following the wires from the speed sensor to the speedo. right behind the $@#&^%# Pep- Boys battery( less than a year old and leaking like a sieve) was a connector with the two wires from the speed sensor ate up and corroded . i replaced with two butt connectors and no problems since. lessoned learned dealers know as much about some of this stuff as i do