Differential maintenance fluids?

[Yetii]

So I’ll be replacing the front/rear differential fluids and transaxle fluid in my 2004 Avalanche 4x4… and seem to be confused as to which fluid viscosity to use…

I hear some people using 80w90 or 85w140, and some people here use Mobil1 Full Synthetic 75w90 for both front and rear differentials?

Transaxle / transfer case fluid is supposed to be AC Delco Auto-Trak II fluid, but is there a full synthetic alternative?

Also, does anyone know the torque settings for all the fill / drain bolts?

And how much fluid in each?

 

[Durwin]

Hello,
I use Amsoil lubricants in my Avalanche. The Amsoil Signature Series ATF in the red bag works for the AutoTrak2 fluid.

Most of the people on here have a 1500, so I won't comment on the differential fluid. I'm sure they make good replacements for those.

 

[ToyHauler13]

Replaced my diff oil this summer. Amzoil 75w-110 Severe Gear in the rear since I do some light towing and Amzoil 80w-90 (recommended weight) Severe Gear in the front diff. Transfer case this summer.

 

[Yetii]

Replaced my diff oil this summer. Amzoil 75w-110 Severe Gear in the rear since I do some light towing and Amzoil 80w-90 (recommended weight) Severe Gear in the front diff. Transfer case this summer.

Would the differential work harder with the 75w-110 if/when I’m not towing? Effect longevity at all?

 

[Yetii]

Hello,
I use Amsoil lubricants in my Avalanche. The Amsoil Signature Series ATF in the red bag works for the AutoTrak2 fluid.

Most of the people on here have a 1500, so I won't comment on the differential fluid. I'm sure they make good replacements for those.

Ok, so when you say Amsoil in the red bag for the transaxle, you’re referring to the one in the middle (“Manual Transmission and Transaxle”), yes?

Also, which one would be ideal for the transmission fluid? The blue (logo) ATF fluid?

(Blue logo = “Fuel efficient”)
(Red logo = “Multi-vehicle”)

 

[ToyHauler13]

Would the differential work harder with the 75w-110 if/when I’m not towing? Effect longevity at all?

I chose the 75W-110 based on Amsoil's info/recommendations. The 75W-110 will just flow like a 110 weight oil when hot (a little thicker). I doubt it would have any noticeable effect on the MPG.

 

[Durwin]

The bag which is the second from the left is the one that I use. As long as it meets the spec, it will work. On website, they list AutoTrack2.

I use it in both the transmission and the transfer case. I think that you have the light-duty 4L60 transmission so your capacity will be different than mine. It's great stuff though. I've been using it for about 15 years now.

 

[Yetii]

The bag which is the second from the left is the one that I use. As long as it meets the spec, it will work. On website, they list AutoTrack2.

I use it in both the transmission and the transfer case. I think that you have the light-duty 4L60 transmission so your capacity will be different than mine. It's great stuff though. I've been using it for about 15 years now.

Wow okay interesting. Is there a reason you chose the “multi-vehicle” (red logo) over the “fuel efficient” (blue logo)?

Also, why not use the one labeled “transaxle” for the transaxle/transfer case??

 

[Durwin]

1. Because I've been using it for 15 years and other than fluid changes, nothing has been done to the transmission even after 233k miles. I tend to stick with something that works.

2. Same reason as the first. The red one says AutoTrak2 on it.

I don't like taking chances with the powertrain. They have never given me any issues since I've had the truck. I think that part of that is the fluids I've chosen. Just my opinion of course.

 

[Auto Parts Guy]

For what it's worth, I use 80W-90 Lucas gear oil on the diffs, and AC Delco Auto Track II fluid in the transfer case. Rock Auto has both for a good price.