QwickerRon

Thanks. Taking it to my dealer Tuesday morning who says they have an excellent transmission mechanic.

Check engine light came on and it was throwing a P0894 code. Did try trailer mode but no change in hard shift. That's just a internal slip code so still not sure what it is. Taking for diagnostics test tomorrow morning. Suspect torque converter.

Not an Allison. I have not tried trailer mode but will try that today. Mr Transmission said I needed to replace the entire transmission. Two other tranny shops say they've never heard of it before. One said perhaps the MAS sending erroneous info to the computer. Just too many tranny shops out there looking for a reason to sell me a 2500.00 tranny. Have a trans shop I'm taking it to next week for more diagnostics to see what they think. A real lack of trust with transmission shops. I'd like some sense of what's going on before taking it

Have an 06 2500 HD w/123K miles. Transmission will drive all day long at speeds under 50 mph and never shift hard. If I drive 7-8 miles at 65-70 mph, like on the interstate, once I slow down and stop and start again, tranny will shift hard between 1, 2 and 3rd. Once I park it for 15 minutes, it's back to normal and no hard shifts. Tran temp gauge does not indicate any overheating. As long as I'm putzing around at speeds under 50, I can drive all day long and never a hiccup. Fluids are okay