Drive Line Fluids

[daberk]

I have almost 80k miles on my truck now and was going to change fluids on differentials and transfer case over to Amsoil products. Is there anything I should know before doing that?

 

[2021QCBH]

The front diff is an odd 75-85 formulation. I just used severe gear 75-90 in both (3.92 truck spec 75-140 for the rear)

Pending your transfer case that changes fluid. Mine is the auto case that takes mobilfluid LT (about the only way to get that in quarts is from Mopar).

I towed from Lexington to Chattanooga in 4x4 in that snow storm last Monday without issues running the 75-90 in the front diff.

The squeeze bags amsoil uses makes it easy and the squirt tip will screw onto the Mopar transfer case bottle as well. I used a new tip for that as to not contaminate the fluid with differential grease.

I ordered 5 quarts of 75-90 and iirc I didn’t open the 5th.

 

[JF19Longhorn]

Changed all mine out with Amsoil 15k(?) miles ago.. used whatever Amsoil stated on their website for all three. I use Auto 4wd a decent amount and tow a decent sized trailer a few thousand per year. Never had any issues. I'm @ 62K miles now.

Make sure you can loosen the fill bolts prior to draining the fluid.

 

[LaxDfns15]

Just answered this in another thread, but I recently changed mine with AMSOIL about 1500 miles ago. Looks like you basically have the same setup as my Rebel with the 5.7 non-Etorque, 3.92 rear, no 4Auto. This is what I paid (with the AMSOIL membership) for fluids, and if you've ever done these changes before all 3 will take you about an hour if you're crawling around on the ground beneath the truck. Spent last week in Memphis driving around in snow and ice constantly switching between 2WD and 4Hi at speeds up to 60mph. No issues/whines/clunks.

80W-90 Synthetic Gear for front diff - $10
75W-140 Severe Gear for rear diff - $15
OE Multi Vehicle Synthetic ATF for transfer case - $35