Help. I got 2008 cummins with 105K and don't pull over 8-9,000 lbs. Tranny started shifting into and out of 4th gear harder and progressed to staying in 4th until about stopped and then changes into 1st. Starts up at 1st, the goes to 4th. after in 4th, won't come out of 4th and when you try to downshift acts like netral and coasts to 1st. Don't think ever slipped but hangs around 4th for some reason. Sure would appreciate any help. Had to run in 4th for several miles the other day and just took kmy time. i never think it slipped. I also changed fluid and filter.Help if you can. Thanks

 

I had a similar problem with my tranny. i found that it went into what they call safe mode or limp mode. I just had to change a sencor that crapped out. Is it throwing any engine codes? have you had it scanned at all? Check grounds as well these trannys really like to act up if they have bad or even dirty grounds as well as battery cables.