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Hello,
My NV4500 has had water inside and although it turns and shifts very nicely, some surfaces in the gears have fairly thick rust. I've been removing as much as I could, and I plan on flushing the trans before I close it again. I won't be able to remove all rust from the wear surfaces and I was going to fill it up with cheap gear oil, run the trans for a few minutes, drain and fill with the proper $$ fluid. Will this ruin my synchros? I really want to flush it this way, but the NV4500 fluid is very expensive.
Thanks,
Mikel
 

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Tough call

I have the same problem except all i got is some discolouration . Rust can be down right nasty . I have heard of guys toasting their trans in a few minutes by running the wrong oil . there is a big discussion on this on Pirate i think . Royal purple has some lube that is rumoured to meet specs and is cheaper.

Toss in some rare earth magnets - say on the back of your PTO covers . This might help capture a bunch of metal crud.
 

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Personally I wouldn't risk cheap oil even for a minute in my NV4500. I would have it disassembled and clean the gears properly. How about the quad4x4 filter kit for them that bolts to the PTO port. How about proper oil and then drop it and filter and reuse if you really want to do it that way. You might think it worked with the quick/cheap oil but How long will it last if you don't do it right? Do IT ONCE DO IT RIGHT.

Gaza
 

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My totally rebuilt (by GM Gear Shop Technician) NV4500 would make a sort of chattering noise when I lugged the engine down to about 800 rpm's with a 10K# tow load. The engine in my truck is a Caterpillar 3204T. Had fresh Syntorq (sp?) in it. The tech told me not to use ANYTHING ELSE! Called Amsoil and talked to a tech person, and he told me to use their 80-90wt gear oil. I was told that it does not have corrosive EP additives, and met the requirements for this tranny. It worked great, and was cheaper than Castrol. No more, I'll call it gear chatter. That's all I use in my NV4500's and I wouldn't downgrade to the Castrol lube. By the way, I have abused that particular trans for 6 years, and 200k miles with no problems.
Bob B.
 
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