Benefits of Amsoil severe gear?

[Interleukin6]

Hi, about to change front and rear differential fluid. I have AAM (SU4) for the front, which takes ACDelco 10-4091 (GM 19300457) 75W-85 High Efficiency Synthetic Hypoid Gear Oil. My rear differential is GM (SU8 with G80 positraction limited slip & GU6 3.42 ratio) which takes ACDelco 10-4122 (GM 19368514) 75W-85 DEXRON Low Viscosity Gear Oil. I see many recommend swapping them with Amsoil severe gear 75W-90 100% synthetic gear lube. Can you confirm this is right fluid for the stock fluids? Looks like our trucks have 2 kinds of front & rear differentials each with their own specific fluid but can this Amsoil severe gear replace any of stock fluid? What are the benefits? Can I change fluid every 100,000 miles if I use Amsoil? I am not hauling or towing anything… thank you.

Edited May 29, 2024 by Interleukin6

[CamGTP]

You can go on the amsoil website too and they may list the fluid you can use when you search by vehicle.

 

My opinion is that you gain nothing. Sure Amsoil is really good stuff but it's going to work just as well as the factory AC Delco fluid or the Valvoline full synthetic gear oil you can buy at Napa down the street.

 

If you don't tow anything and don't run it hard, you can still stick with the same 75,000-100,000 fluid changes if you really wanted too.

[Haufski762]

Bingo.

[Grumpy Bear]

3 hours ago, Interleukin6 said:

Hi, about to change front and rear differential fluid. I have AAM (SU4) for the front, which takes ACDelco 10-4091 (GM 19300457) 75W-85 High Efficiency Synthetic Hypoid Gear Oil. My rear differential is GM (SU8 with G80 positraction limited slip & GU6 3.42 ratio) which takes ACDelco 10-4122 (GM 19368514) 75W-85 DEXRON Low Viscosity Gear Oil. I see many recommend swapping them with Amsoil severe gear 75W-90 100% synthetic gear lube. Can you confirm this is right fluid for the stock fluids? Looks like our trucks have 2 kinds of front & rear differentials each with their own specific fluid but can this Amsoil severe gear replace any of stock fluid? What are the benefits? Can I change fluid every 100,000 miles if I use Amsoil? I am not hauling or towing anything… thank you.

 

They are both 75W85. The rest of the description is mumbo jumbo. Although I am a Red Line guy, the AMSOIL Severe Gear 75W90 is as about as good a diff lube as it gets. Why? Viscosity stability. Stays in grade. Nice easy fill packaging too.  

[Interleukin6]

It seems that the prices of the original ACDelco fluids are similar to the Amsoil. The benefits I think are only one fluid treats the front & rear both (I need different fluid for the front & rear if use ACDelco) and I don’t need a fluid transfer pump… Can I use a brake cleaner to clean up the differential gears when the covers are opened? Of course I will thoroughly clean the inside of the covers, but I think I need to clean the gears as well before putting in Amsoil to prevent contamination. Is this overkill? Thanks.

Edited May 30, 2024 by Interleukin6

[Grumpy Bear]

Change the oil and call it a day. 

[Interleukin6]

How about this... The front differental does have enough space to work... If I just suck up old fluid then put new one without the cover off and removing metal debris on the magnet, is there no point to do this or is it better than nothing?

[Grumpy Bear]

10 hours ago, Interleukin6 said:

How about this... The front differental does have enough space to work... If I just suck up old fluid then put new one without the cover off and removing metal debris on the magnet, is there no point to do this or is it better than nothing?

 

You know that gasket is reusable, right? 

[diyer2]

If you plan on keeping this truck for a long time, change it with Amsoil Severe Gear. Well worth the effort and cost.

Any gear lube will work, changing it is important. I like Amsoil.

Edited June 1, 2024 by diyer2

[Interleukin6]

I think the gasket for the rear is reusable but not for the front.

[Grover67]

9 hours ago, Interleukin6 said:

I think the gasket for the rear is reusable but not for the front.

 

 

Yes you are correct and depending what truck you have there are different gaskets

 

-grover67