Tranny failure ??
 

I own a 2002 ram 2500 4x4, cummins diesel automatic,,the tranny is going in & out of drive ,,seems like it goes into nuetral for a second then back into gear,,only happens in 3rd & overdrive,,worse when cold ,,truck has 156k on it,,is this a sign of tranny failure ? pressure loss ? can I adjust bands ? thanks in advance for the input,, Mark

Is the fluid burnt? (black and nasty smelling)

There are no bands applied in 3rd or OD

Are there any transmission codes stored in the computer?

Your tachometer will tell you the rpm rise when it seems to go out of drive, could be the converter unlocking which will give you a 200 or so rpm rise or it could actually be kicking out of OD which will give you a several hundred rpm rise. The converter unlocking is a known problem and it's caused by electrical interference; it can also be caused by a faulty TPS or misadjusted brake light switch.

With that many miles I would pull the pan and replace the filter...a clogged filter will cause your problem.

The fluid is NOT burnt,,I drain the pan every time I change engine oil,,I have installed a drain plug in the tranny pan,,makes it easy,,the fluid I drain out seems as clean as the new stuff i put back in,,converter locking & unlocking seems logical,,I,ll look into it,,,Thanks

Here's a link to one commentary on the problem, a Google search will find others.

http://www.kentsoil.com/dodgebug1.htm