replacing abs unit

I am about to get another ABS unit for my 91 PA (with traction control) but every unit seems to have another part number. Also you can't find any information about these part #'s at the internet.

According to Rockauto there are 4 different ABS units in the PA between 91-95, an early and a late unit, both with and without traction control.

Does anyone know more about that, how to distinguish the ones with and without traction control for example?

My newer Buick has an off off switch on the shift lever the the traction control, maybe?

Most of the time the 91-95 units will be labeled with a sticker that says " Traction "

There are differences, but I am not sure if the ABS pumps will cross from say a 93 to your 91.. 91-93 EBCM/EBTCM are under the dash iirc, then 94-95 had them on the drivers strut tower.. Wonder if the pin outs are the same...

It seems that the 91-93 Traction pump is the same and the 91-95 W/O Traction is the same from what I can gather..

Wish I had the straight answer for you...