Not sure on a C3, but I think it is either the pinto tranny or a 2 speed. Irregarless, not worth fooling with.
The C4/C5 has a pretty much square pan on it. Can either be a case-fill (also called a step case C4, bellhousing bolts to the pump) or a pan fill model. The pan fill (bellhousing bolts to the case) model is generally the one with more clutches and is considered the heavy duty C4/C5. Either one, the tranny is three pieces, bellhousing, case, tail housing. The C5 is basically a C4 with a modified valve body and a centrifugal lock up converter. The C5 came about some where in 1980. The same mods for a C4 work with a C5 as does the 67-80 C4 valve body/transbrake.
The C6 is longer than a C4/C5 and is heavier. The case and bellhousing are one peice, so the C6 is a 2 piece tranny, case& bellhousing as one and then the tail housing.
Then you have the FMX, it is 3 pieces also, but the case is case iron.
Hope this helps.
<font size=-1>[ This Message was edited by: Just Strokin on 2/10/02 11:09am ]</font>