So I'm picking up a 91 RS convertible for my new project and I have a deal lined up to get a LH6 5.3 and a 6l80e tranny. Has anybody ever done or heard of this tranny swap in a thirdgen? I'm choosing this tranny over a 4l60e because I want to have the 6 speed auto with paddle shifters. Will it fit in my thirdgen with simple tranny swap parts or will I have to do some more modifications? And will it work with the 5.3? This is gunna be my 1st time building/swapping a motor and tranny so I'm trying to get as much info as possible before I start. Thanks!

 

The 6L80 is about the same length as a 700R4. Your problem will be the girth of the transmission. You most likely will have to modify the transmission tunnel to some degree. They do fit T56 transmissions in there with no problem though. So you may not have to modify the tunnel to much. Also I don't know how much ground clearance you will have. You might have to use the G8 transmission pan.


The other problem will be mating the new ECM and wiring harness with the existing wiring harness. It can be done if you have experience in that field.