In my case I switched the fluid from ATF+4 to Mercedes recommended Mobil Delvac 50. I thin with Amsoil 5-30 Synchromesh. This combination has proven effective in long haul applications and cuts the noise down considerably.
I've stood next to a Superduty with the conversion and it sounded like rocks were in the tranny.
Good info on the fluid. My 2001 Silverado only has 56,000 miles on it and the ZF 6 speed has sounded like the case is full of rocks since the day it was new. I might have to give that fluid a try. On top of the inherent ZF trans noise, the release bearing/slave cylinder assembly rattles like crazy at idle when the clutch is disengaged. Been like that since new as well. The dealer even replaced the bearing/slave cylinder assembly 10 years ago when the truck was still in warranty. No change.
Maybe Larry would know, I would like to get a late model GM with the 5.3 and toss in a NV4500....not having any luck on my intergooglemachine searches. Pretty sure it will bolt up, it is the computer that is the problem.
Manuals were not offered from GM behind any 5.3L engines but it can be done. Should it be done to a stock truck and would it be a worthwhile swap?...prolly not. Many people are swapping 5.3L engines into older vehicles using various transmissions, including NV4500's by using the flywheel part number from a 4.8L/6.0L. ECM calibrations can be tweaked by any good tuner such as Howell Engine Development, Nelson Performance and many more to do a root canal on the automatic bin files and accommodate manual trans bin files.
Thanks and good to know about the shift patterns...
Turns out the truck was an auto (so many false positives when using car.com/autotrader/etc)...so the search is still on.
Not set on a diesel so a gas option might work out better with the 5spd
You will have much better luck finding a 6.0L/NV4500 over an 8.1L/ ZF S6-650 as many fleet trucks were built with smaller engines backed by the NV4500. Back in the day GM bought and stored thousands of them for future use when New Venture Gear started having major financial issues.
The 6.6L diesel/ ZF S6-650 might be a little easier to find than 8.1L/ ZF S6-650 though. There are two model years where the NV4500 was behind an 8.1L but it was not in a pickup truck but rather the GM 3500-HD chassis cab (2001-2002). My point with that is the NV4500 is a strong trans and can live up to torquey big blocks and Cummins engines (Dodge's). I wouldn't be worried about a NV4500 behind a little 6.0L gas. The only reason why GM went with the ZF in the GMT800 HD trucks in the first place was because it was predicted the supplier, New Venture Gear, would collapse leaving them without a source of 6 speed manuals, which inevitably NVG did fold where even Chrysler had to find a new transmission source of transmissions (Getrag) when flow of NV5600's dried up. The automotive manufacturing industry has been a jacked up mess for the last 10 years with a different supplier going out of business, being taken over, etc, everyday but it an exciting field to work in. What is today, is different tomorrow. Crazy
Interestingly enough, even though GM discontinued manual transmission in full-size trucks for the US market, they continued to offer them in the Mexican and South American markets. For those markets GM uses a Tremec 5 speed but I can't remember the trans model number. I've never seen one of those transmissions in real life but they look stout in pictures.