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TCU question.... converted 90 tranny to '92
Posted: Thu Sep 02, 2004 12:37 am
by bretgem
1990 Legacy wagon auto AWD. Had a 92 tranny put in along with the correct rear diff, but the mechanic forgot to put in my replacement TCU. As much my fault as his since I forgot to tell him I had one, but what do I do now? Is it something I can pop in myself? Why am I changing it in the first place (I am sure there are reasons - just curious)?
Thanks! Bret
Posted: Thu Sep 02, 2004 2:18 am
by vrg3
The TCU is easy to remove and reinstall. First remove the trim panel above the driver's knees using a Phillips-head screwdriver. Then identify the TCU; it's a gold box held to the bottom of the steering column with two 10mm-head nuts. It should practically be staring you in the face. Undo the three wiring harness connections by pressing the tab on each connector while pulling it away from the TCU, and then undo the two mounting nuts with a 10mm socket on a long extension.
I forget -- it might be easier to disconnect the wiring harness connectors after the unit's unmounted.
I don't know how much it matters which TCU you use... Does it not drive well? I guess a different final drive ratio could adversely affect the shift points.
I remember ciper once saying he'd interchanged lots of different TCUs successfully, including putting one for a 95 Impreza into a 90ish Legacy.
Anyway, if you have the 92 one maybe you should just try both and see which works better.
Posted: Thu Sep 02, 2004 3:32 am
by Legacy777
TCU question.... converted 90 tranny to '92
Posted: Thu Sep 02, 2004 1:07 pm
by bretgem
thanks guys - when I posted this I had hoped somehow I might be able to get a diagram - - so the excellent description and the picture helped a ton - - I'll let you know if i run into any problems and need further help.
Bret
this was wayyy to easy
Posted: Fri Sep 03, 2004 2:18 am
by bretgem
Thanks again - went in nicely.... took all of four minutes, but then i lost most of the screws for the panel, so my total time increased to about fourteen as a result. Thanks for saving me another trip to the mechanic!
Posted: Fri Sep 03, 2004 3:22 am
by vrg3
Cool.
Lots of us don't even know where that panel is anymore... I took mine out the day I got the car and have kept it out ever since.
Posted: Wed Sep 22, 2004 3:24 am
by kpurcell
Just curious, did the TCU swap make a difference.
I recently changed tranny/diff from 3.9 to 4.11 (auto tranny)
Does the TCU car that my ratios are different?
Anyone else w/ TCU experience (preferably on automatic) ?
