What weight gear oil..

[DEERE3594]

I SHOULD know this, butttt...

What weight gear oil do y'all recommend for 2002 GM 14bolt full floater with the G80? I live in Ohio, so it gets cold, do more running around empty then towing..

(it seems Ive forgotten half the stuff I use to know about trucks since I dont have to be a weekend mechanic 'wrenching on my 6.5s anymore )

 

[Mad Maxx]

I run 75w90 Amsoil with no Problems.

 

[THEFERMANATOR]

75W90.

 

[DieselCash]

I put 80W90 in my rear diff when I changed out the oil and put the new diff cover on.

 

[DEERE3594]

any additive needed for the G80?

 

[Mad Maxx]

I never added any.

 

[DieselCash]

Neither did I

 

[tanman_2006]

I run 75/140 Amsoil due to heavy towing, no additives. 75/90 would work just fine for a DD.

 

[btfarm]

any additive needed for the G80?

No additives. It must be synthetic though. Mobil1 is about the best. Many of us have had grabby issues with the Amsoil Severe Gear. In any case 75w90 is your best bet.

Sent from my SCH-I535

 

[THEFERMANATOR]

You don't want an additive with a G80. It doesn't play well with the design or the clutches they have.