Alright so I swapped a LT1/4L60E from '96 Chevy Impala into my buddy's '94.5 (that's what he calls it) Buick Roadmaster.
We have both the '94 & '96 PCM and we only have the '94 wire harness.

Someone mentioned to me that the '95+ trannys are PWM, unlike the pre '95 trannys. Also the VSS is different and located on the other side of the tranny. Can my friend use this tranny without modifying the internals? Will he have to use the '96 PCM? Will we need a '95+ wire harness? Will a tail shaft swap solve the VSS problem?

Your help is much appreciated, thanks.

 

The tail housing swap will solve the VSS, As for the PWM that is correct, You can however solve this also. The 94 does not have wiring for the PWM solenoid. What you would need to do is eliminate the PWM function in the valve body. If you email me at performabuilt@yahoo.com I have instructions to easily do that in word 2007 format.
Also you will want to swap the 3-2 solenoid its a different ohm reading, Its also notable that the 3-2 strategy is a little different between those years. However from past experience driving cars with this type moded to work trans I found no noticable issues with that.

 

So a '95+ wiring harness solve the issue if we use the '96 PCM? I'd rather swap a harness than modify the tranny.

 

Yea, using a 95+ wiring harness would accomplish the same thing, but modifying the valve body is actually very simple. Us B-Body guys have been doing it for years.

 

You know of any write-ups?