CHECK YOUR DIFFS...

64BAwagon · June 20, 2023

Okay.... heres the info directly from GM's 2024 Silverado/Sierra service manual 16637297, document 6122676

"10 inspect the axle lubricant level, it should be 0-10mm (0-0.4") below the fill plug opening."

"11 If the axle lubricant is low, add lubricant until the level is 0-10mm (0-0,4") below the fill plug opening. Use the appropriate axle lubricant.

It also says that the initial fill volume should be 3.17 qts or 3.0 liters

It looks like the folks at American axle need to adjust their fill process.

For anyone that intends to address this with their dealer I included the document numbers for reference just in case they try to sandbag you. These are specific to the 2024 models.

Some members posted this info earlier so I included the document number since its specific to the 24's

Scott

Edited July 11, 2023 by 64BAwagon

diyer2 · June 20, 2023

Fill it to the hole, a cup maybe?

64BAwagon · June 20, 2023

I added about a pint to mine and its still below the level specified. Mine took just under a qt to fill properly

Edited July 7, 2023 by 64BAwagon

64BAwagon · July 7, 2023

Has anyone here either notified their dealer service dept of the low level or taken their truck in for the level being low ?

My concern is that GM will not take this seriously without any evidence of them being shipped with low fluid levels. This is not on the PDI list at the dealer or factory. Unfortunately most people will never check theirs and the majority of dealers dont when doing an oil change. The potential issue is that there are trucks in service with differentials that are 30% low on fluid (according to GM's own documents) What will this do to the longevity of these units ?

diyer2 · July 7, 2023

Wake up. They don't care.

64BAwagon · July 7, 2023

Wouldnt be the first lost cause I was associated with. At least I can say I tried instead of just complaining.

Pryme · July 11, 2023

On 7/7/2023 at 3:27 PM, 64BAwagon said:

Wouldnt be the first lost cause I was associated with. At least I can say I tried instead of just complaining.

The fact most everyone if not every single person who’s checked it, has reported it low, is very disappointing. I’m glad I checked and just drained it and treated it as a break in fluid and put a fluid that absolutely crushes the stock fluid in every test I’ve seen.

64BAwagon · July 11, 2023

Unfortunately the only way to get it documented is to take it to the dealer and have them open a warranty issue on it. Since most if not all of us have corrected our own there's no documentation. I reached out to the service manager at the dealer I took delivery from and he related the warranty claim. He did however say that he knows a couple of people in quality control at the plant and that he would pass along the concerns. There's another member on here who spoke with his dealer after he corrected the issue and they even gave him a qt of the fluid to replace the one he used. I have also reached out though another person I know and I am told they have been made aware of the issue. How far that will go is unknown.

It all comes down to American axle short filling them. Unless GM starts to spot check the units when they come in or the dealers begin to add it to the PDI I doubt anything will change.

Its not like GM has a history of ignoring things until they become a bigger problem, think ignition issues about 15 yrs ago.

Edited July 11, 2023 by 64BAwagon

BB68 · July 11, 2023

Whats weird is every PDI I have ever preformed included checking every oil reservoir. How do so many get out of the dealers like this? and the dealers that do catch it, are they eating this cost, repeatedly?

64BAwagon · July 11, 2023

My understanding is that the dealer PDI now has fewer boxes to check and doesnt even include a road test like it used to.

My 2021 had a pull in the front that I noticed 100 yds down the road when I left the dealer.

I drove it the next day to a shop I have done business with for many years. They have been family owned since the late 30's. Turns out the caster was off on the right front. I got it fixed properly even if it cost me a few bucks.

ssgballistics · August 27, 2023

Did the initial oil change on the new truck today. Checked the rear diff while I was at it. Like everyone else, I was pretty low. It took an entire quart to bring it to just below the fill hole. Dad had me go ahead and check his 21’ as well. Same thing. He had me go ahead and do a drain and fill on his. His has a drain plug so easy service. Took about 4 QTs to bring it to just below the fill plug.

Kerry Pulaski · December 9, 2023

GM dealer parts dept. printed out the attached GM lube document #5258436, for my '24 2500HD (and 3500). Says 75w-90. He double checked with his service manager, with my question of the "LS" version of 75w-90,

being "LS" for Limited Slip Diff. additive.

Said NO, not needed, just the Synthetic 75w-90. Makes sense as (@Grumpy Bear) stated the HD axles are "Lockers" not a Limited Slip clutch type. Also reason on one very tight 90 deg. corner of my shop stone driveway, it chops up the packed stone at 10 mph.

My 2500HD a Unicorn of sort, as the option "Max Trailer Pkg.", gave a 12 in. rear axle, frame and spring overload pack from a 3500HD. GVW at 11,700.

So I guess the HD Locker Axle is what is called the G-80.

Thanks to (@Grumpy Bear) also for posting the 75w-90 viscosity test chart. Most informing on the brand results.

Happy Holidays, All !

GM '24 H.D. LUBRICANT LIST #'s.pdf

Kerry Pulaski · December 9, 2023

On 7/11/2023 at 6:12 PM, 64BAwagon said:

My understanding is that the dealer PDI now has fewer boxes to check and doesnt even include a road test like it used to.

My 2021 had a pull in the front that I noticed 100 yds down the road when I left the dealer.

I drove it the next day to a shop I have done business with for many years. They have been family owned since the late 30's. Turns out the caster was off on the right front. I got it fixed properly even if it cost me a few bucks.

(@64BAwagon) Mentioned the Front end Alignment pull.....Same experience. My new '16 2500HD, drove off the lot, going home pulled hard right, even on left side of crown of a secondary road. My 3rd. trip back to the dealer for #3rd. alignment fix, as still pulled right wicked bad, service manager said will put his 26 year veteran tech on this issue.

As he drove a 1/2 mile, said he does not agree with the GM H.D. alignment specs, and if I would let him put his own special sauce spec's on her.

40 min latter, said I drive. Darn spot on perfect. Can now drive with thumb and index finger, not a death grip. Specs attached. Glad to say my '24 H.D. is good out of the box.

Just adding a Suspension MAXX steering stab. shock kit, tho, as the H.D.'s still wobble the steering wheel a lot on gravel. On the highway it's great.

GMC ALIGN #3_12-6-17__RIGHT CASTER INCR.pdf

Kerry Pulaski · December 9, 2023

Service manual #16637297, is this PDF downloadable ? as (@64BAwagon) posted an except from it.

Pryme · December 9, 2023

6 hours ago, Kerry Pulaski said:

GM dealer parts dept. printed out the attached GM lube document #5258436, for my '24 2500HD (and 3500). Says 75w-90. He double checked with his service manager, with my question of the "LS" version of 75w-90,

being "LS" for Limited Slip Diff. additive.

Said NO, not needed, just the Synthetic 75w-90. Makes sense as (@Grumpy Bear) stated the HD axles are "Lockers" not a Limited Slip clutch type. Also reason on one very tight 90 deg. corner of my shop stone driveway, it chops up the packed stone at 10 mph.

My 2500HD a Unicorn of sort, as the option "Max Trailer Pkg.", gave a 12 in. rear axle, frame and spring overload pack from a 3500HD. GVW at 11,700.

So I guess the HD Locker Axle is what is called the G-80.

Thanks to (@Grumpy Bear) also for posting the 75w-90 viscosity test chart. Most informing on the brand results.

Happy Holidays, All !

GM '24 H.D. LUBRICANT LIST #'s.pdf 428.95 kB · 3 downloads