2005 2500 5.9 cummins 4x4. Previous owner had Transmission rebuilt in Feb 2014. Truck sat for a few months due to needing injectors I bought the truck with about 1000 miles on the trans. I have all paper work for the rebuild. The problem I am having now is when I put truck into drive it feels like the trans is lagging going into gear. Now if I put I into to 1st manually I have nothing at all. And when. I put it into reverse I'll have nothing for about 20-30 seconds the it will shutter alil and try to go into gear but then it stops. I'm thinking it has something to do with the torque converter I'm not really that knowledgeable about these transmissons. I have taken it back to the shop it was rebuilt at because it has a warranty and the guy wanted me to check all the grounds fist and make sure even had a good connection. It went into gear fine for him at this point after i haf it towed to the shop. He said the pcm was commanding it to go into lock up but it wasn't acutely locking up. After this I drove it home. Shifted gears fine. Went and made sure all grounds were good. And now I'm having this issue. Just trying to get an idea of what's going on so I don't get the run around at the transmisson shop

 

Take it back to him
Definitely sounds like something in the trans.

 

It's definitely going back. Still has the warranty for the rebuild. Just trying to get an idea on what it could be so I don't get the run around at the shop

 

Could be a number of things. Accumulator issues most likely