91 trooper tranny woes... HELP!!!!!

Good people,
I've had my tansmission (91 trooper automatic 4x4) rebuilt recently and since then, I haven't been able to drive the car for more than one full day wihtout it flashing the check transmission light and putting it into "limp" mode. It goes in and out of it. I've taken it back to the local shop where the tranny was rebuilt three times already, first they perfomed a test and traced it to some faulty wiring, now they are saying it is the transmission control unit and tell me its another $600 :eek7: for a new one to be installed.
As much as I like the car I cannot justify spending more than it is worthed, since i'm already over $2200 into it.
Would it be worthed to look for an used control unit?
How much something like that would be?
Is it difficult to install?
HELP!! I'm going :screwy:

Do you still need help with this?

Well, I bit the bullet... Now I'm told that the control module for this particular car is a Bosch unit and it costs $900!!! Is this true? So we're putting a rebuilt unit in... Is this car a POS or what??? I do appreciate your offer, if only to make me make sense of all this.

Well, I bit the bullet... Now I'm told that the control module for this particular car is a Bosch unit and it costs $900!!! Is this true? So we're putting a rebuilt unit in... Is this car a POS or what??? I do appreciate your offer, if only to make me make sense of all this.i have a 1990 lx and have had the trany rebuilt by the dealer 3 times as well! i have a ton of info on this suv. but i can make it shortand sweet. this trany was use in the troopers from nov,1989 - march,1990 it is the same trany that is in toyotas and bmw's. it was not powerful enough for the trooper and they eliminated it right away.the trany will never last more than a few years, no matter how many you puy in! aparently the trany that replaced it can work in the 89-91 troopers, but that is the only way to stop the problem, you must put in a completely dirfferent trany.

I am having the same transmision problem with my 91 trooper V6 2.8L. The transmission light comes on and it goes into limp mode, I am confused, should i get the tranny serviced or start looking for a new tranny?

i have a 1990 lx and have had the trany rebuilt by the dealer 3 times as well! i have a ton of info on this suv. but i can make it shortand sweet. this trany was use in the troopers from nov,1989 - march,1990 it is the same trany that is in toyotas and bmw's. it was not powerful enough for the trooper and they eliminated it right away.the trany will never last more than a few years, no matter how many you puy in! aparently the trany that replaced it can work in the 89-91 troopers, but that is the only way to stop the problem, you must put in a completely dirfferent trany.

So what kind of transmission are you recommending?

I am having the same transmision problem with my 91 trooper V6 2.8L. The transmission light comes on and it goes into limp mode, I am confused, should i get the tranny serviced or start looking for a new tranny?

mine does the same thing.... I wish I knew what was going on, I'm thinking of just redoing the drive-train anyways and putting in combos from other well built gm vehicles.... I'm thinking 3800 series engine... cant think of what tranny to use though...