NV4500 gear lube change suggestions

[gscig50]

Anyone have any dos or don’ts when changing the gear lube on 96 Chevy C2500 NV 4500 trans?

 

[RichLo]

YES! You need to be careful what fluid you put in there.

The Amsoil in the link below is the easiest to source, they list NV4500 right on the bottle. Others hopefully will chime in as there are better OEM fluids out there... I think one is from Dodge?

https://www.amsoil.com/p/amsoil-75w-90-manual-transmission-transaxle-gear-lube-mtg/?code=MTGQT-EA&gad_source=1&gclid=Cj0KCQiAhc-sBhCEARIsAOVwHuQFwRbaCoxJqOhkvyptOIt_V-g9ePqVWyK_OKeNL1yC6JN3OgRBnA4aAn1eEALw_wcB

 

[bluex]

The OE GM an Dodge fluid is nearly impossible to get. The next best is redline MT85 as it most closely matches the spec of the OE fluid. Amsoil would be my 3rd choice. MT85 is readily available on Amazon or local parts stores.

The carbon syncros in the NV series trans are very picky about what you put in them. The wrong stuff will cause accelerated wear an you'll be doing a rebuild before you want to.

 

[GM Guy]

Echoing the previous sentiments, I run Amsoil equivalent to the gm 12346190 spec and get along great.

We ruined a nv4500 years ago with royal purple. They are definitely picky.

 

[movietvet]

You can use 75w-85w Mobil Delvac 50 GL-4 synthetic fluid.

 

[someotherguy]

I swear I'm gonna filter my existing fluid through a bunch of paper towels and just put it back in. (KIDDING)

My NV4500 is due for a rebuild and I'm glad we're talking about replacement fluid because finding/using the correct stuff is a concern of mine. Of course it's irrelevant if you replace the OEM carbon-fiber synchros with plain ol' bronze. Specific fancy lube for NV4500 no longer relevant at that point.

Richard

 

[someotherguy]

You can use 75w-85w Mobil Delvac 50 GL-4 synthetic fluid.

This one has me confused. The original Castrol Syntorq LT (repackaged by GM and Dodge) is supposedly 75W85 with whatever secret blend of additives to protect the carbon-fiber synchros the NV4500 came with.. but one of the suggested replacement fluids, the Mobil Delvac 50, is named that because it's 50W. I've seen the Delvac recommended in more than one place now including by a transmission builder out of TN and I'm just trying to make it make sense.

Richard

 

[movietvet]

You can use either. As long as is synthetic and either one of these.

 

[someotherguy]

I've seen that Redline MT85 mentioned as well, being suggested as a direct replacement for OE. Hell Mopar even suggests using ATF+4 as long as it's not in a heavy-duty application. That just seems wild to me. Saw a screen shot somewhere of engineers and SRT group saying that it's OK, and the SRT guys seem like a sharp bunch.. but they're also not paying for my transmission rebuild.

The issue around the carbon-fiber synchros is the big one, and for a while I didn't think they were still available new. Recently I stumbled across a site that said they had them in stock, but I'm not sure where that was now. Despite the specific lubricant requirement, it seems like they're the way to go, to maintain the smooth(ish) shift feel and attempt to keep it from feeling like a heavy truck transmission.

Richard

 

[gscig50]

Thanks for all the replies guys. After much reading on the subject I purchased the Amsoil recommendation. My understanding is that it’s got to be GL-4 and definitely not GL-5 to protect the synchros. Thanks again for the input.