If you want to know the difference in the trans, check out Marlin's site and if you still have any questions, call him. You will also find some things that you might want to replace such as the clutch, shifter seat or add a short throw shifter kit.

If you have the extra money just get the trans from him or the rebuild kit and rebuild the trans before installing it. The Heavy Duty version of the W56 is a great trans that I have been running for the past couple years but the best is the 151F which I will be installing this fall.

BTW - I would recommend the W56-D trans as it has a reverse syncrow brake and is the only W56 with an external vent. Try car-part.com to find one.

Adam W.
87 4Runner SR5 - 22RE w RV head & TRD Cam, LCE header, W56B-HD, 4" Stage II, 1.5" BJS, Rancho T-bars, F 5.29, R 5.29 ARB V6 FF w LC disks, 35" MT/R's

85 4Runner frame, 5" Marlin springs, 5:29 ARB HP front. Work in progress - Always!