I have a 99 2500 with automatic Transmission that was just rebuilt and a new two disc tc. The first time I drove it after the rebuilt the transmission shifts quickly from 2nd to 3rd to 4th(O/D). It doesn’t happen when your foot is really in it but when you accelerate normally it jumps up and the engine bogs down. 

 

The transmission guy that worked on the truck told me it was an electrical issue on the APPS sensor but I want to get some other suggestions before throwing money at the wrong problem. Also the APPS sensor is a few months old

Scan the truck for trouble codes, that is always a good starting point. 

Do WT ground mod and check for AC noise  

TV cable not adjusted properly.  Might be to loose causing quick shifts under light throttle. 

I'd look at TV cable first. I haven't done at mod nit I have gone through and cleaned all battery connections. I also haven't check for ac noise.  In 15 years my alternate is one of the few things I haven't had to replace..

 

I have had battery cable issues and it caused all kinds of weird shifting

 

Check terminal block below driverside battery for losses connections. I gues that's the grid heater. Those were loose causing me issues to.

 

Good luck 

Thanks for all the posts. 

 

I’m plannin on doing the WT Mod soon. 

 

I’m at work til Thursday but I’ll start trouble shooting when I get off work.

 

Any more info on the tv cable? Where to start when checking?

 

 

Thanks again

4th gear and TCC lockup are not affected by TV cable. They are electronic. One wire to the trans is grounded to engage lockup, another wire is grounded to engage OD (4th).

 

Here's some copied information from the FSM:

 

"

3-4 UPSHIFT OCCURS IMMEDIATELY AFTER 2-3 SHIFT
1. Overdrive Solenoid Connector or Wiring Shorted. 1. Test connector and wiring for loose connections, shorts or ground and repair as needed. 2. TPS Malfunction. 2. Test TPS and replace as necessary. Check with DRB® scan tool. 3. PCM Malfunction. 3. Test PCM with DRB® scan tool and replace controller if faulty. 4. Overdrive Solenoid Malfunction. 4. Replace solenoid. 5. Valve Body Malfunction. 5. Remove, disassemble, clean and inspect valve body components. Make sure all valves and plugs slide freely in bores. Polish valves with crocus cloth if needed.

 

"

Edited June 12, 20196 yr by kzimmer
More Info

Great info.

Still check that TV cable

Sorry for the long delay. Work and life has been crazy!!

 

so I started small and cleaned all the terminals. Checked the a/c noise. Ended up replacing the alternator. I checked the tv cable and it appeared to be good. I wasn’t 100% on how to adjust it on the 99.... 

but it sure is shifting better now. It does seem when in OD and the tc locks up the rpms can drop to 1200 or so

 

the only thing left to do is the w-t mod and to my recent surprise a new oil pan gasket. 

 

 if any one has done the oil pan gasket and has any tips they would be much appreciated