My '99 Ram 3500 shutters coming out of conv. lock-up 3rd or 4th gear under significant load. This is most noticable when Edge Comp is active (low level). Trans shop says they can see no issues. Oil clean, not burnt, no contaminants. Gov pressure good and testing showed no signs of slippage. They suggested engine issue or programmer issue. These also have been checked by a deisel shop and check out good. Shop manual suggest fluid breakdown may cause this so fluid was changed(not flushed) and Lucas conditioner added. Problem is a little better but not gone. Transmission has 35000 miles on it with aftermaket torque conv. Suspect a worn clutch pack in Trans, but before this expense of a rebuild I thought I would ask for other ideas>>>>>>Thanks

 

you sure its a trans issue?
i never add trans fluid conditioner and its not recommended by dodge.
so i take it by pressure showed good they checked CVI's and all that with line pressure?
possible could be a not fully unlocking torque converter or something similar.

need more info before i can have more words