98.5 Cummins Automatic can't find correct gear

[ircked]

We recently purchased a 98.5 dodge 2500 cummins automatic. Here is the problem, when you hit about 45 it shifts up then down then up then down and all over. holy cow. I remember many years ago i drove a new one and it did the same thing. i was unimpressed. this seems to be worse. it continues even as you increase speed. does anyone know if one of the programmer units will fix this? is this a common problem on the automatics?

 

[Cumminalong]

This is actually a pretty common problem.

The good thing is, there is USUALLY a very simple fix.......

Ya ready for this?..........

Clean your battery terminals.

Yup! That's right. Pull the battery cables off, clean them up really good and reconnect.

Betcha the problem goes away.

 

[gmctd]

Even if that heals it, have the fluid and filter changed - not flushed: changed, which involves dropping the pan for the filter change - they'll try to talk you into a flush because it's more lucrative, but a '98 is sorta long in the tooth at 20yrs old, and as X# owner, you likely don't have any idea of the condition of the fluid and filter that currently resides there - have them let you look at the detritus in the bottom of the pan - if there's lots of brown\black wet powdery stuff, that's band and clutch material, and you should consider a rebuild

If the fluid doesn't have a burned odor, and the powder is only slight, they can go back together with it and adjust the bands for improved driveability

Next would be the throttle position sensor, which is like the volume controls on the old radios, B4 digital - they would get scratchy after awhile, and lubing them would stop the noise for a few days, but replacement always cured the problem - the throttle position sensor is a variable resistor just like those volume controls and has the same failure symptoms - when they go scratchy, the trans tries to respond - they're 'scratchiest' at normal traffic speed positions, around 30-35mph, 45mph, 55mph, 65mph

 

[WilliamBos]

but a '98 is sorta long in the tooth at 20yrs old,

You mean 10 years old.

 

[gsnick]

Most of the 4th gear hunting is caused my alternator noise/grounds read this link and try it before chucking 400+ $ for an APPS, you can also try re-setting the apps, some have had good luck with that and it costs nothing,

Grounding mod:
https://www.atsdiesel.com/PDF/120505/4th hunt 46 47 RE.pdf

I gotta go dig around for some links

 

[gsnick]

Heres another one, this is what I did on my truck and it cured my hunting issues:

http://www.suncoastconverters.com/dodge/drewirekit.html

 

[gmctd]

Yep, my bad with numbers, as usual - at only 10yrs old it still may have a short tooth or two - still should have the transmission properly serviced and checked for your own peace of mind - also, checking connections and grounds is a good idea, incl removing the corrosion around the battery terminals\cables - get those red\green battery-post felt washers, use vaseline on the posts and cable clamps to prevent reoccurance in damp weather