I have a 94 Diesel Ram 3500 Auto with over drive... I notice the tach jumping up a few hundred rpm's while driving down the road. I can set the cruise at 60 mph on a flat road and once in awhile the tach will jump up and down... Iam pretty sure its the convertor kicking in and out , but why ???? Its not under any load driving down the road ..and it dont do it all the time .

 

A lot of people have posted about this, I know because mine started doing the same thing and I searched.
The general concensus is that the grounds are faulty. This weekend I'm going to go from batteries to tranny and clean all the electrical connections.

 

Thanks
let me know if it helps ..

 

Not really. It shifts less but still does it between 45 and 50 on average traffic kind of driving. on acceleration to highway speeds it doesn't do it anymore though.

 

My '01 was doing the same thing and I reset the APPS, and the problem went away. Read my earlier post:
https://www.dieseltruckresource.com/...d.php?t=111930

To reset the APPS:

This procedure has shown to help 24 valve ISB engines. It is basically teaching the fly
by wire accelerator on these trucks to reread the position of the pedal and it's limits.
Most complaints this will help with is poor acceleration, improper shifting, bucking in 5
and 6 speeds. Has been known to increase fuel mileage in some instances.
1. Set parking brake
2. Disconnect negative battery cables on both batteries
3. Turn ignition key to run(to drain any remaining capacitors)
4. Let truck sit for 30 minutes( this is the recommended minimum)
5. Return ignition to OFF position
6. Reconnect both batteries and secure, not a timed event
7. Turn key to run position(not start) and depress accelerator pedal slowly all the way
to the floor
8. Allow pedal to return to top position slowly
9. Turn ignition switch OFF
10.Release parking brake

 

check out the throttle position sensor, also the speed sensor on trans. your 94 should have both. there is a lot of info here on site. do a search.

frank