48re overdrive issue

[Cummins_04]

I have an 04.5 cummins and it will not go into overdrive.
I have an edge cts and it says that the truck is going into 4th but if you press the tow haul button it goes to 3rd but the truck doesn't change at all
Think it is a solenoid issue or what?

 

[LAmiller]

Probably a overdrive piston seal failure, put a line pressure gauge on the overdrive port, it'll tell a story

 

[Mopar1973]

3-4 accumulator spring breaks, seals get hard and fail as mentioned above, clutches/steels could be burnt/warped