Computer after changing Trans?

[gold2day]

I recently had to change our transmission with a used one.I(not thinking) put 'our' torque converter on this tranny.It drives decent,but not like it should or like it used to.If you go from a stand still and gun it,it'll shift fine in the 1,2,and then when it gets to 3rd it revs up,back off the gas,and it'll sloowwwly goes into 3rd.That and if you're driving it down the road and holding steady,it'll drop,say 5mph,and then it'll pick up by itself after 2 or 3 secs..Would it be that I should put the torque converter from the used tranny instead of our old one or does the computer have to be set up(so to speak) for this transmission?My ole lady is having a fit to get her baby back,so PLEASE any info or suggestions would be greatly appreciated!BTW,it's a 1994 Explorer,4.0 motor,push button 4 wheel drive

 

[PopRichie77]

Nothing should have to be done to the computer. You should not have used the old converter. If your old trans failed badly contamination could have got into the torque converter. By using the old TC you may have contaminated the new trans valve body. Also did you flush the trans cooler and lines? To late now if you didn't.
Last of all you could have got a bad used trans.