I think 54's were all closed drivelines. Thanks for the great advice guys, I'm leaning toward rebuilding the three speed and putting in the 3.55 gear. I suspect my truck has the heavy duty 3 speed but how would I tell for sure? Also I'd need to replace the gear shift lever,(mine rusted and broke off and is braced with a metal splint and duct tape) which may mean replacing the upper control shaft - parts I have not found in any of the catalogs. How tough of a get is this?
