i'm having rear end busting shifts on my 04 2500 cummins powered 48re from 3 to 4 (up shift only)and when tq con. locks up when pulling heavy load (14,000 lb backhoe). i bought truck new and it just started this. has 88k miles.

 

sounds like the TV valve is stuck I can't remember which year has the TV cable or TV actuator either way a cable can bind up as well the actuators are known to bind up as well

 

So is it 3-4 or when the converter locks? Or both?

TV cables continued until 05, when the changed to the TV motor set up. Of all your other shifts are fine then I don't expect the TV cable to be the issue.

 

it's both 3 4 & tq lock up & only under very heavy load. doesn't do it pulling my 25' camper only when pulling my gooseneck loaded in excess of 10K. i have a soft shift issue from 1 to 2 but i think thats a band issue -it wouln't adjust. i've got the tranny out now but i haven't torn into it yet.

 

keep this thread posted I'll be interested to hear the problem
your right I miss read the problem TV would affect all shifts
do you have any accessories such as BD pressure lock or a torque locker of any kind?

 

tranny is bone cold stock. running diablo sport power puck, turbo pressure turned up with boost elbo, and full 4" inch exhaust from turbo back

 

Have you got a lift and/or bigger tires or anything like that?

 

no lift & factory size tires. truck is all stock except for the power puck, turbo boost, & exhaust.

 

sounds like an accumulator piston siezed

 

Updates??