Truck Repair: rise in rpms, dodge 3500, deisel

Question
I have a 1995 dodge 3500 deisel dually. My problem is that while driving every so often the rpm's jump maybe 200 rpm's there is no loss of speed but you can hear the motor race. I brought it to a transmision place and he hooked it up to the computer and told me nothing is wrong. it seems the problem is not registuring on the computer. Another tranny guy told me it might be the computer or a relay telling the tranny to kick down. If you could shed some light on this subject it would be greatly appreciated

Answer
A 95 model has a manual engine in it.If it was going into kick-down mode you would probably know it.I dont beleive I have heard of that before.You know we mostly work on low power complaints,not running or going dead kind of problems on Dodge.I couldnt tell you about the rest of the truck since I only work on the engines.