rear end fluid

[rblanch]

Has anyone checked their rear end fluid level? I did because this is the 3rd HD I bought 2011-17 and 20 and all came a quart low on the fluid. When I checked the owners manual it doesn't specify what to put in it just says see your dealer. Am I missing something. Shouldn't it be filled to the bottom of the fill hole. On my 2017 I added a whole quart. I'm going to get the dealer to top it off on the 1st oil change.

[Jay P]

Nope... From the owners manual. This is for a 2019 since the 2020s tell you not to check it but it's the same axel.

 

"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."

Edited January 16, 2020 by Jay P

[Black02Silverado]

1 hour ago, rblanch said:

Has anyone checked their rear end fluid level? I did because this is the 3rd HD I bought 2011-17 and 20 and all came a quart low on the fluid. When I checked the owners manual it doesn't specify what to put in it just says see your dealer. Am I missing something. Shouldn't it be filled to the bottom of the fill hole. On my 2017 I added a whole quart. I'm going to get the dealer to top it off on the 1st oil change.

You didn't state exactly what model you have but you can find some good fluid information as in capacities listed here in the AMSOIL look up guide.

[redwngr]

7 hours ago, rblanch said:

Has anyone checked their rear end fluid level? I did because this is the 3rd HD I bought 2011-17 and 20 and all came a quart low on the fluid. When I checked the owners manual it doesn't specify what to put in it just says see your dealer. Am I missing something. Shouldn't it be filled to the bottom of the fill hole. On my 2017 I added a whole quart. I'm going to get the dealer to top it off on the 1st oil change.

 

5 hours ago, Jay P said:

Nope... From the owners manual. This is for a 2019 since the 2020s tell you not to check it but it's the same axel.

 

"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."

 

As  Jay P points out, if you filled the previous gen to the bottom of the hole it was overfilled.

 

For 2020+ GM has a new rear axle (built in house iirc). 

They haven't indicated the fill level (and on previous gen it wasn't the same for all differentials.

As noted, they also haven't indicated the fluid in the OM, but for the previous generation hd's it was a synthetic that was used front ant rear.  (1500's used same in front, but called for 75W85 in rear)  

 

SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in Canada 89021678). 

 

 

The transfer case on 2020 calls for DexronVI

[rblanch]

It specifies the trans and transfer case but noT the differentials. It does have the part no for the 2017. I refilled it with the amsoil severe gear around 25000 if it’s overfilled it has not given any problems. The 2020 is a srw 3500. I need to make sure it is filled going to the Daytona 500 with the 5th wheel in 3 weeks it’s definitely lower than .08 lower than the hole.