Hello everyone.

I should change VSS and PSS on my '98 Blazer. Using maintenance manuals I identified 3 sensors, one on Gearbox and 2 on transfer case.
I would like to know if all of three are the same (same p/n) or are different.
Can someone tell me? On Rockauto site I found only VSS.
LAst question: anyone know if there's a mail address in GM where to ask for this info?
Thanks a lot!