Originally Posted by shaggy1970AS
Maybe he meant the Max Payload package? Was max payload avail in 3.55?
OP Easy check, how many lug nuts on your wheels?
HD Payload also requires 3.73 gears. The diff for Max Tow may be either the e-locker or the 7-lug limited slip, HD Payload is only on the limited slip and includes Max Tow in the package.
There is an option that's just the tow package (not Max), which gets you the trailer brake controller, upgraded trans cooler, tow/haul software, etc. You don't get the extending mirrors, among other things.