Transmission upshift problem

[Jwissler10]

I have a 2005, and am fighting an OD upshift problem. Ever since my transmission rebuild my truck tries to jump to OD around 48-50mph with anything between 23-50% throttle. If I have less than that or more it holds longer but is really quick to upshift. If I am pulling a heavy load up a long hill and it bogs/lose speed, it will downshift, lock in 3rd for a couple seconds then upshift and repeates. I have a smarty and udc pro so have tried adjusting the upshift, turning on the factory od off feature but the truck still functions the same way. Prior to my rebuild my truck would shift later, and if pulling a hill downshift and hold 3rd lock until I let off throttle then it would upshift.

im sort of curious if anyone has had the same issue, could then be a faulty solenoid, or transducer, or TTVA? Or maybe a bad wireharness grounding and causing the truck to try and jump to od? No codes on my truck either.

 

[cerberusiam]

The 48-50 mph shift to OD sounds right for stock tuning. Probably the result of having a transmission that now transfers the power correctly. You can adjust the rpm to throttle percentage for the 3-4 shift, both up and down shift with Pro RT, just have to change the curves to see what will work.

 

[Jwissler10]

Well I sort of thought that for a stock truck, but I saved maps that changed it to shift at 2050rpm at 0% 2100 at 9.75% 2200 at 20% etc essentially adjusting stock maps up by 300 rpms, the maps changed under light throttle but more than 23% it ignores and shifts at 1800. It also ignores the od off feature and shifts anyway which is leading to my thought of it being a ground or physical issue over computer controlled. Does that make sense or am I on the wrong path?

also before the rebuild it would downshift and hold if I was in the throttle, now it downshifts, locks then upshifts immediatly, when I have a 12k load up a long grade I can't hold 50-55mph in 4 lock at 1350rpm so I either tow it at 45 in 3rd lock or 70 in 4th lock but sure wish I could do it at 50-55 in 3rd lock at 2000 rpm like I did before the rebuild. I can't for the life of me figure out why a new rebuild would change the behavior of a computer controlled shift point.

 

[cerberusiam]

There is no OD Off for an 05 so the program is likely just not there. You have to flash it with a TCM program to do that and then you lose the lockup algorithms.

Best advice, OD Lockout box.