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Discussion Starter #1
Since the HD 5 speed doesnt have a forum in the tranny section I thought I'd asked this here...

What fluid/oil is used in the 5 speed manual in HD trucks? Whats the recommended change interval?

My new 2500HD should arrive in a month or so and I've been making a list of maintenance stuff to buy... havent found this info anywhere yet.

Thanks!
 

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5 spd??? must've got the 6.0 engine, 8.1 and Dmax get 6 spds. Just check the owners manual
 

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Discussion Starter #3
yep, its a 6.0 :thumb:

I dont have the truck yet (see sig) or the owners manual for that matter lol.
 

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All depends upon which 5 spd they use.... the old NVG4500 used conventional gear oil, some of the others use ATF, while still others use a special fluid from GM, call the dealer and ask the parts guys, they'll likely give you a GM part# but they usually know the generic term, I.E. atf, gear oil etc.
 

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Yep, NV4500. The GM spec oil is a another one of these special brew mystery oils that GM refuses to release the specs on. The oil is a synthetic 75W-85 GL-4 made to GM spec by Castrol and sold under the brand name Syntorq, but you cannot buy it from Castrol or any retailer. It is only sold at your dealers parts counter under part number 12346190 and lists for $21.22 per quart and you will need 4 quarts. Not knowing the specs of the GM oil, I would not take a chance on running anything else. Btw, the 6.0 with this tranny runs great. Use 1st gear during the breakin, but after 500 or so miles, use 2nd for normal starts. A little hard getting into reverse when cold, so leave it in reverse overnight so you'll be ready to back straight out in the morning.
 

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Discussion Starter #8
Yep, NV4500. The GM spec oil is a another one of these special brew mystery oils that GM refuses to release the specs on. The oil is a synthetic 75W-85 GL-4 made to GM spec by Castrol and sold under the brand name Syntorq, but you cannot buy it from Castrol or any retailer. It is only sold at your dealers parts counter under part number 12346190 and lists for $21.22 per quart and you will need 4 quarts. Not knowing the specs of the GM oil, I would not take a chance on running anything else. Btw, the 6.0 with this tranny runs great. Use 1st gear during the breakin, but after 500 or so miles, use 2nd for normal starts. A little hard getting into reverse when cold, so leave it in reverse overnight so you'll be ready to back straight out in the morning.
Thanks, thats the info I was lookin for.

Is it the same gm mystery synthetic that they run in the rearend that lots of folks are substituting mobil1 75W-90 for? I'd planned on changing front and rear diff's at 500 miles and switching to mobil1, wonder if the same would be ok for the NV4500 too?
 

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Mobil 1 75W-90 is fine in the axles. I use Royal Purple 75W-90 because it is slightly thicker than the M1 without having to go all the way to a 75W-140. Nothing I could find from AAM who makes the axle, and Eaton who makes the locker require you to use the GM spec oil, only a good synthetic GL-5. The same thing cannot be said about the manual trannys, both the ZF-6 and the NV require a specific lubricant. Since manual trannys dont have oil pumps and are splash lubricated, they are very sensitive to weight, viscosity and other specs to insure adequate lubrication and protection. There is no way I would use M1 or RP or any other lube in these trannys without knowing the exact GM spec. My old NVs had drain plugs, the new one does not. What I heard was that so many Dodge dealer mechanics were draining these trannys and refilling with an unapproved lube and blowing them up, that Dodge ordered the drain plug eliminated and instructed dealers that tranny oil was now not serviceable, or filled for life. I havent decided if I'm gonna attempt to change mine out, but if I do it will be with the GM spec oil.
 

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Discussion Starter #10
ah ok, guess I'll leave it alone then... especially if theres no drain plug.

Thanks :thumb:
 

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Dodge ordered the drain plug eliminated and instructed dealers that tranny oil was now not serviceable, or filled for life.
This is becoming more and more common. A lot of Toyota trannies have been "abused" by Iffy Lube monkeys doing pan drain and refills with Dex-III when T-IV is required. The newer models are using the Toyota "WS" (World Standard) fluid and they don't even have a dipstick. There is a fill port similar to that on a manual, but for all practical purposes, it's sealed.

Amsoil claims that their ATF is compatible with Toyota T-IV, but yet Mobil states that theirs is completely incompatible. Other than Amsoil (if you trust it), the dealer is the only source for T-IV.
 

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......

Hey,

So what year did GM delete the drain plug on the manuals? 5 speed only, or ZF6 too? How would you change it? Pump it out the fill hole?
 

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The ZF-6 has a drain plug. Only the NV4500 (not sure about the NV3500) now has no drain plug. Dont know what year it got deleted either, but think its pretty recently. My 92 and 97 had one, the 05 does not. Only way to get the fluid out is to suck it out, or maybe pull the side cover but not sure on that one. Need to look into it further.
 
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