My truck was running fine and after being parked about 2 hours I couldn't get reverse. In drive there was slipping. I could get up to 25mph and it was okay, no noise or shudders, and it just dropped on me, no grip at all, I'd let it settle back into 1st and it'd be fine until I hit 25 aagain. The diagnostic showed no codes, there was no electrical alerts, and upon mechanical inspection, fluid full, no residue or shard in the pan.....???? The mileage is 83,000. No work has been done on this transmission since previous owner had purchased new.
when tech opened it up, the factory stuff was still there......so filter and fluid hasn't been done. Anyone had a similar issue?

 

yeah, i just did. damn you jinxed me. everything is the same except reverse, i have no problem going into it...