need rear axle lubricant info

94yj · August 27, 2020

i had a shop change the rear end oil in my 2015 silverado 2500hd and i don't think they added the friction modifier to it when they changed it as my rear end is acting funny and trying to lock up on right hand turns my question is how much of the friction modifier does it need in the rear axle how many ounces please let me know asap thanks

redwngr · August 28, 2020

Front Axle – Four-Wheel Drive SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in Canada 89021678).

Rear Axle (1500 Series) SAE 75W-85 Synthetic Axle Lubricant (GM Part No. 19300457, in Canada 19300458).

Rear Axle (2500/3500 Series) SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in Canada 89021678).

For all 6.0L 2500HD Series applications,

the proper level is from 0 mm to 13 mm (0 to 0.5 in) below the bottom of the fill plug hole, located on the rear axle.
Add only enough fluid to reach the proper level.

. For all 6.6L Duramax Diesel 2500HD Series applications and all 3500 Series applications,

the proper level is from 17 mm to 21 mm (0.6 in to 0.8 in) below the bottom of the fill plug hole, located on the rear axle.

Add only enough fluid to reach the proper level.

G80 is NOT supposed to have additional friction modifiers.

Edited August 28, 2020 by redwngr

94yj · August 28, 2020

2 hours ago, redwngr said:

Front Axle – Four-Wheel Drive SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in Canada 89021678).

Rear Axle (1500 Series) SAE 75W-85 Synthetic Axle Lubricant (GM Part No. 19300457, in Canada 19300458).

Rear Axle (2500/3500 Series) SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in Canada 89021678).

For all 6.0L 2500HD Series applications,

the proper level is from 0 mm to 13 mm (0 to 0.5 in) below the bottom of the fill plug hole, located on the rear axle.
Add only enough fluid to reach the proper level.

. For all 6.6L Duramax Diesel 2500HD Series applications and all 3500 Series applications,

the proper level is from 17 mm to 21 mm (0.6 in to 0.8 in) below the bottom of the fill plug hole, located on the rear axle.

Add only enough fluid to reach the proper level.

G80 is NOT supposed to have additional friction modifiers.

thank you it is greatly appreciated on the info

94yj · September 4, 2020

for those that maybe having problems like i had i called a shop that does not do anything but axle repairs and they said the g80 has clutches in it and i had them add the additive and my rear axle is back to normal with no problems with it now

txab · September 4, 2020

I would not follow the advice of the poster above, if equipped with a G80. As exhibited many times on this forum and others, the G80 requires no additional friction modifier. Added friction modifiers can induce issues with the G80, again, well documented on this site and others.

The info for the G80 provided by Eaton is correct

Edited September 4, 2020 by txab

newdude · September 4, 2020

1 hour ago, txab said:

I would not follow the advice of the poster above, if equipped with a G80. As exhibited many times on this forum and others, the G80 requires no additional friction modifier. Added friction modifiers can induce issues with the G80, again, well documented on this site and others.

The info for the G80 provided by Eaton is correct

x2 here is the link to Eaton's piece on the G80: https://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&noSaveAs=0&Rendition=Primary&dDocName=PCT_1628996

"Maintenance free; requires no lube additives"

94yj · September 4, 2020

4 hours ago, txab said:

I would not follow the advice of the poster above, if equipped with a G80. As exhibited many times on this forum and others, the G80 requires no additional friction modifier. Added friction modifiers can induce issues with the G80, again, well documented on this site and others.

The info for the G80 provided by Eaton is correct

JMHO all i know is it worked for my purpose and the vin number on my truck shows it came with the g80 and the axle shop has been in business for over 35 years and is an Eaton service center amongst other major axle manufactures and like i said before i had them add the additive on every right turn the rear end was acting like i was on rocks and and now on right turns the axle is quite as it was when it was new

Edited September 4, 2020 by 94yj

94yj · September 5, 2020

4 hours ago, newdude said:

x2 here is the link to Eaton's piece on the G80: https://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&noSaveAs=0&Rendition=Primary&dDocName=PCT_1628996

"Maintenance free; requires no lube additives"

my rear end locker looks different than that one but by vin and all the part number i wrote down from what was on the ring and pinion and bearings all return to a g80 per the gm parts dept but and one gm tech / shop foreman that has been with gm for going right at 50 years said their was 2 versions of the g80 one is like you pictured in the link and the other one which i have is a Eaton no spin 14 bolt 10.5 ring gear but still marked as the g80 what happened to axles back in the 80s back that were simple

Edited September 5, 2020 by 94yj

txab · September 5, 2020

What are your RPO codes for the diff?

davester · September 5, 2020

From what I've read, GM and Eaton don't specify adding friction modifier to the gear lube for G80's, and that works for most people, but some people find it chatters a bit sometimes for them, and adding a bit of friction modifier makes that go away, and it still works properly.

94yj · September 6, 2020

just an update my truck has the rpo code g80 in the glove box and also by vin but it does not have the g 80 locker design it has the Eaton limited slip aka eaton no spin and has clutches so beware not all g80 rpo codes are the same at least in my 2015 the true eaton does not take additive but the limited slip has clutches and requires the friction modifier to be added