Changing fluid front diff , transfer case, and rear diff.

[redwngr]

4 hours ago, newdude said:

 

 

Looking at the 2024 owner's manual for a 1500, the only fluid they call for a change interval for severe use is the transfer case every 50,000mi.  Oh and transmission every 45,000mi.  Normal use, transfer case every 100,000mi.

 

For 2024 HD, normal use its transfer case every 50,000mi, severe use its every 25,000mi.  Transmission is only called out for severe use, every 45,000mi.  

 

Neither schedule calls for front and rear axle lubricant replacement.  I even went back to 2010, no diff servicing mentioned then either in the maintenance charts.  

 

 

Thinking on this, AAM was sole and is still a supplier to GM for axles.  I seem to recall AAM had a tech note or something from them about diff fluids.  Good luck if I can find it now, but they actually called for an oil change at 500mi on their products due to their initial break-in.  GM calls for that 500mi, but they mention nothing about changing the diff lubes out.  

 

 

 

 

 

 

 

Thanks!

I had been wondering of the service manual(s) was different than the owners manuals.

 

I also thought I remembered reading about 'lubed-for-life' for the diffs. 

Perhaps from about when they switched to synthetics for the diffs. (not sure when that was)

 

My 2011 OM lists the synthetic products used -- but no change interval for diffs.

Call for Dex in the transfer case and has change schedule based on usage. 

 

2011 Sierra OM

 

 

Does the service manual indicate the same axle lubes as the OM did in 2011?

Even without a change interval they probably list what product to use if they are opened for repair. 

- 2023 Sierra OM says to 'see your dealer' for diff fluid info

 

I guess it's now 80W-90 synthetic for all diffs?

[newdude]

11 hours ago, redwngr said:

 

Thanks!

I had been wondering of the service manual(s) was different than the owners manuals.

 

I also thought I remembered reading about 'lubed-for-life' for the diffs. 

Perhaps from about when they switched to synthetics for the diffs. (not sure when that was)

 

My 2011 OM lists the synthetic products used -- but no change interval for diffs.

Call for Dex in the transfer case and has change schedule based on usage. 

 

2011 Sierra OM

 

 

Does the service manual indicate the same axle lubes as the OM did in 2011?

Even without a change interval they probably list what product to use if they are opened for repair. 

- 2023 Sierra OM says to 'see your dealer' for diff fluid info

 

I guess it's now 80W-90 synthetic for all diffs?

 

 

80W90 is long gone.  Even on a 2011 they replaced it with 75w90.  The part # for 80w90 supersedes to the 75w90 #.    

 

So 1500s use 75w85 now.  GM has two different lubricants based on who's manufacturing the axle, AAM or GM.  What the difference between them is other than scent (grape vs. vanilla), I don't know, but both are high efficiency GL5.  

 

HDs use 75w85 in the front, 75w90 out back.  

[redwngr]

Thanks.

 

It' wasn't what I typed, but I was thinking they would all be the synthetic product (75W-90) listed in the 2011 OM screen grab.

[Z45]

The axles/transfer cases are filled by the unit manufacturer (not by GM on assembly line) using minimum requirement, aka good enough lubricants.   

There's obviously better made lubricants on today's market that meet and exceed OEM and do a much better job in the long run. Regardless of what brand lube is stated or advertised by the OEM, they are nothing more than contracts that go to the lowest bidder.   Mass production and cost concerns lead to "good enough", but not necessarily the best available. Look at OEM tires, for example, decent quality, "good enough" quality, but not necessarily the best available. The same could be said for gear lubes, automatic transmission fluids, oils and filters.

Edited November 2, 2024 by Z45