4 speed overdrive automaticwell im almost sure its unlocking ,it only does it on the free way and not all the time. Seems like it just does it occasionally when i dont want it to. Rarly does it happen in town at low speeds. The fluid is full and the tranny was rebuilt about a year ago. It also shifts hard into first under throttle the other gears shift smooth. Also it seems to lack power,almost like something is holding it back. Not slipping but as if it were in second when i take off.A friend of mine has a dodge truck that does the same thing at about 65 mph, and he said it does it most of the time but once in a while it dosent. I am tottally lost. I been working on cars for a few years and have encountered most problems and done alot of above average/shade tree work but have never seen a vehicle do this...what it does to a tee,ill get on the gas and it will like kick into a passing gear like and go back and forth till i let off the gas,kinda like a slip but not a slip,like it cant make up its mind

This can happen if your engine isn't running correctly.

I,ll try and answer this one,,you said it act,s like it,s kicking in ,,and out,,does it actually slip,,or is it kicking in and out of lock up mode,,if it,s just jumping in and out of lock up mode,,there is a lock up switch,,located in the tran,s when you pull the pan off,,if it get,s dirt in it,,it Will cause this condition,,if it is slipping,,the torque converter wont actually cause it to kick in and out,,if it,s low on fluid,,this will cause it to do that,,or if it,s getting stopped up,,on the filter it will also do that,,if you had provided me with a little more info,,i probably could tell you what it is doing,,i been a certified mechanic for 35 yrs,,i hope what i have told you help,s some.

trans type re4r01a. two possible problems, one is the cable to the throttle body is mis adjusted, same as your friends dodge. other is possible valve body problem or solenoid problem. to fix this go back to your tranny man or find someone with true trans knowledge and real diagnostic skills.