I've had success with running Amsoil in the NV4500 that's in my puller. It use to be a daily driver a few years ago, swapped it from Syntorq to Amsoil oil when 5th gear went out.
okay. I dont like ive seen Amsoil on the shelf at oriellys. but cant be to hard to get a hold of. Should i put rub the sycros down with petroleum jelly or would putting that on em srew them up? ( i know the sycros are picky)
I just rebuilt my 4500 last weekend and filled it with Amsoil. I bought it from Amsoil's website and it showed up in 2 days. I've got about 100 miles on it and its shifting good. I didn't put anything on the synchros when I assembled it since I was waiting on the Amsoil but before I bolted the shift tower back on I slowly poured 1 qt of fluid over the entire mainshaft as I slowly rotated it and called it good.
"Ideal for NV-4500 Transmissions
AMSOIL Synthetic Manual Transmission & Transaxle Gear Lube is a thermally stable, extreme pressure formulation that resists heat, oxidation, acid build-up and varnish. It is the ideal gear lube for high temperature applications, including the New Venture NV-4500 transmission, which retains heat due to its cast iron housing and is often subjected to heavy loads and high torque from turbo-diesel engines.
AMSOIL MTG is the replacement fluid for GM part #12346190 and Chrysler part #4874459 (Chrysler specification #MS-9070)."