Im driving a 95 12valve auto with 191K on the odometer. It is on its second tranny in the truck. The new tranny was installed a year and a half ago and has about 30k miles on it. The new tranny has an ATS TC, bigger valve bodies, and a shift kit. It also has a deeper oil pan and trans temp gauge.

The truck drove perfectly fine up until yesterday. Started driving down the highway and it started searching for gears erradictly. Going 45 the trans was still trying to stay in 2nd then finally shift to 3rd and if i let off the pedal it would quickly shift to 2nd or even first again. It will not even go into 4th gear. I did search some of the problems associated with this sort of issue and thought that the TPS was most likely the issue. I replaced it with a brand new unit (230$) and it is still doing the exact same erradict shifting. Driving down the highway in 3rd gear and if I take my foot off the pedal it quickly downshifts. What else besides the TPS could my problem be?

Take into note the tranny fluid is clean and toped off and the temp gauge is reading no higher than 120*(even while running in 3rd at 60)

 

TV cable or TPS signal noise? Dunno...

There's something Ive seen about TPS signal noise and I'm thinking it may act like that.

Could also bee in the VB. Governor solenoid, etc.

Just guessing.

 

define tps signal noise

 

could it have anything to do with the neutral safety switch? this was disconnected and the plug seems pretty worn out.

 

I think the TPS only effects the lock-up.

 

also found a wire with a plug in connection to another wire disconnected. this was also attached directly below the tps. anyone think this could affect anything? the inside of the plugs are rotten out on one side. ill post pictures in a little bit of what i am talking about.

 

I think electrical noise on the TPS signal wire might also affect 3-4shift, but yeah, probably not all the way down to 1st gear.

In '95 the RH didn't have PCM controlled governor pressure, so if not the TPS, then the only other thing than internal VB issues is kickdown/TV cable binding or sticking.

 

Check out these pictures of the cable connection I found that was disconnected and corroded out. It is located directly under the TPS in the same wiring harness but im not sure what it leads to. Any significance? (they are the pictures labeled Truck)

http://community.webshots.com/album/561783045hRJFTh

 

I think that plug is for the fuel heater. The wire should go to the top of the fuel screen bracket (thermostat switch) by the lift pump then more wires go to a plug into the fuel heater element below the bracket. Looks like it had a meltdown. the fuel heater element may have been removed because it has been a trouble spot for fuel leak back. I doubt you need a fuel heater.

Your shift problem may be the return spring broke on the TV cable. Or the TV cable may be screwed up. The TPS only controls OD and CL. NOT 1-2-3 shifts. A TV cable problem could prevent the trans from shifting into OD or CL as well as 1-2-3 shifts. Check spring and Tv cable movement and adjustment.

 

The spring is still connected to the tv cable so how do I tell if it is bad? How can I tell if the tv cable is bad or needs adjustment?

 

Have someone sit in the truck(off) and depress the pedal slowly to the floor and release. Watch the TV cable and make sure it pull fully out and then returns fully in when released.

Especially check on the tans end and make sure it isn't binding. For some reason I think I remember binding at the trans to be an issue.

 

turns out its the pigtail connection at the tps. anyone know where i can get one (boneyards in the area do not have a single cummins)?