cowboyup007

So your driving down the road at highway speed and you let of the throttle for a split second and it will kick out of overdrive, or when your driving at like 60 km an hour it will constantly kick in and out... very frustrating any ideas?? Please help, also every now and then the speedo won't work which won't allow it to shift into overdrive, but that's only happened a few time... Possibly a broken or rubbed through wire??? Or bad speedo sensor??? Or tps??? Please help!! Thanks you. Ps truck is a 1993 ext cab cummins dually with automatic and 456 gears.

Rampage1967

Try a new TPS.
Speedo is the speed / distance sensor on the trans.
Make sure you check the connector / wiring before replacing the speed sensor.

1STGENFARMBOY

First do as sugested check all the conections, I would try a new speed sensor down on the side of your transfercase, if it goes bad it causes the same symptoms as your describing.

it's about 50 bucks or so.

Onemoparnut

Look in the sticky there is a procedure for testing the tps that is probably causing it to kick in and out of od on you. The intermittent speed problem might just be a bad connection at the vssclean that connection well before you spend any money on it that was what was wrong with mine.

DPFservice

Mine would kick out of OD when I let of the pedal and turned out to be a bad TPS. Fixed it with a pot like the sticky says to and now no problem. Didn't realize how nice OD is until it doesn't work properly.

NJTman

I thought my TPS was bad as well, as it was doing the same thing you describe.

If you follow the procedure in the sticky, and adjust the TPS to spec. you might find.... as I ultimately did.... that it was simply out of adjustment. After Bringing it back into spec. the trans has shifted perfect ever since

KISS

(keep it simple stupid)


Always try the simplest procedures first, before you automatically assume the worst.

T.

1STGENFARMBOY

cowboy is it kicking out of O/D at the exact same time as your spedo messing up ? ?

Rampage1967

Mine went bad a couple years ago & I made a bracket to replace it with a 3.0 gasser unit. It's been working perfect since.
A nice side effect of this is the 3.0 unit has more travel than the stock unit so it doesn't readjust itself every time you floor it with the high idle screw backed out.

1STGENFARMBOY

That right there is some good info.

Dar

cowboyup007

Within the past 3 or 4 months when I got in the truck and started driving the speedo or the od wasn't working, so I'd shut it off go do what I had to do and start it back up and for the most part it would work, but for the past littlee bit, while I'm driving at highway speed and I let up on the throttle the small a mount it will lick out of od, or when I'm cruising through town it will constantly kick in and out of od, if you have truck under load or like full throttle it won't kick out of od, just as soon as it see the littles throttle decrease... Its frustrating when your driving a 110 and it kicks out of od and the ol cummins is just screaming then