Can I replace my TH400 or 700R4 tranny with a 4L60E or 4L80E?
Yes, but be prepared to do a lot of work to get it to fit and function. The converter for the 4L80E is a huge and heavy. And it’s not cheap. A rebuilt unit will probably cost $1000 to $2000. Of course the driveshaft will have to match up and you will definitely need an aftermarket computer controller. Accel, Turbo Action, and Premier Performance Transmissions make them. They cost around $650 to $700 which includes the wiring harness. In order to use it, you need a throttle position sensor of some kind on the motor. Engine RPM is needed as well and it may be possible to pick it up from the tach. You might also need to convert to an electronic speedometer. Your best bet is to call Precision Turbo 708-418-5227. They’ve done a number of these conversions, but mostly on fuel injected cars.
