what is the preferred oil for GV units? book says 80/90 but it had some clear thinner oil in it, looked like the syn 50wt we use in roadrangers.
Thanks
Russ
Thanks
Russ
Gear Vendors oil
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ATF. big no-no on gear oil
Alan Slingsby
Full Access Member
Towcat,would that be the same for US gear units? I know they are same-ish but wanted to know for sure when I seen this thread,thanks
us gear and doug nash used atf,, worked on several, but never a gear vendors.
icanfixall
Official GMM hand model
My GV book recommendation is a synthetic gear oil made by Mopar #04874459. The GM oil is#12346190 or GM#1052271. This was an added sticker on the front of my install manual. Might want to give them a call to see if something new has come up. My info is from 6 years ago.
Really! I thought the Doug Nash/U.S. Gear units used gear oil...thank you!!
jaluhn83
Full Access Member
Are you sure about US Gear /DNE using atf? Everything I've heard was gear oil, and it looks very much like the type of trans that would use gear oil - big heavy splash lubed helical gear trans.
I decided to take a look through the manuals I have, and this manual states that one quart of 80W-90 gear oil is needed to fill the U.S. Gear units. Maybe the Doug Nash units were different? Take a look at page 14:
http://dieselwarden.net/temp/usgear/US Gears overdrive manual.pdf
This maual corroborates that info, on page 7:
http://dieselwarden.net/temp/usgear/Dual Range.pdf
I was going on info from DNE when they were in business years ago. So I would use the manual recomendation for that era of unit.
Sorry for the mis info.
I am going to use tractor hydraulic/ wet brake oil. meets/ exceeds all atf specs, and I have seen it at 400* and it still lubricates a scraper diff ,which is a high speed planetary with wet brakes.
Sorry for the mis info.
I am going to use tractor hydraulic/ wet brake oil. meets/ exceeds all atf specs, and I have seen it at 400* and it still lubricates a scraper diff ,which is a high speed planetary with wet brakes.
Dumb question, Russ, but is there any chance that the info you had was for the Corvette units as opposed to the truck units?
Alan Slingsby
Full Access Member
Thanks that answers my ? 80/90 is what I need when I change it! Too late to read all that info,I will have to come back to that. Thanks for that posting Warden
jaluhn83
Full Access Member
There's basically no mechanical difference between a DNE2 and a US Gear - certainly nothing that would make me think they changed lubricants.
To me gear oil is used for most well, gearboxes..... ATF is designed for forced lubrication and systems that use the fluid as a hydraulic fluid as well - ie automatics. Gear lube is not good for a system designed for ATF mainly due to being too thick - it'll damage pumps and such.
Not really sure why/how the ZF and other manual trannies use ATF. I think much of the reason is reduced drag for economy reasons, but am not sure.
To me gear oil is used for most well, gearboxes..... ATF is designed for forced lubrication and systems that use the fluid as a hydraulic fluid as well - ie automatics. Gear lube is not good for a system designed for ATF mainly due to being too thick - it'll damage pumps and such.
Not really sure why/how the ZF and other manual trannies use ATF. I think much of the reason is reduced drag for economy reasons, but am not sure.
idiabuse
Full Access Member
Been using AMSOIL MTG 75W90 for the last 14 years in my GV still works great everyday, Actually changed my oil in the unit today!
Javier
Javier
jaluhn83
Full Access Member
Well, apparently it's worked well for you, but personally I would quiet strongly advise against using that oil in a GV, because the GV uses oil for hydraulic shifting. That is, you have a little pump in there that pressurizes the oil and uses it for pressure lube and clutch application. Yes, Amsoil is great stuff, but that's still gear oil and going to be much thicker than ATF. I would expect that to cause damage/stress to the pump and possibly cause issues with the clutch shifting, since IIRC the viscosity of the oil is used for metering and timing.
Same reason you wouldn't use gear oil in an automatic trans.
Remember, the GV trans is kin to a standard automatic transmission. US Gear/DNE is kin to an old heavy duty manual trans. Fluid should be considered accordingly.
Pretty much anything with a pump should use ATF - get a hand pump and try pumping atf and gear oil to see why.
Same reason you wouldn't use gear oil in an automatic trans.
Remember, the GV trans is kin to a standard automatic transmission. US Gear/DNE is kin to an old heavy duty manual trans. Fluid should be considered accordingly.
Pretty much anything with a pump should use ATF - get a hand pump and try pumping atf and gear oil to see why.
idiabuse
Full Access Member
Inside the GV is a cone with friction material that does the actual grab, no clutches, the rest are planetary gears like an automatic. AMSOIL is some great stuff and they recommend MTG 75W90 for the GV unit also.
All I can say I change the oil whenever I have to pay attention to the GV, I just changed it again because after rebuilding the C-6 on the floor the other day I lost some fluid out the vent hole, had to replenish or change, I had also a blown fuse for the GV so when I put the C-6 back in the GV did not work, so I was sort of spooked.
I had my GV apart before and the only wear item in the unit is the friction they use on the cone, it rains down into the sump, this is why they want oil changes every 5000 miles on the GV unit. I have gone as much as 30,000 with clear oil draining out of my unit. 26 mpg with a dually sure is nice theses days...
