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Rear Axle Differential

8.6K views 11 replies 5 participants last post by  Mattaleca  
#1 ·
How can I find out which rear axle I have? It's an overland 2wd hemi. I see the manual shows one with ELSD and one without, also one for front and rear which I'm assuming is for the 3.6L. Just like to keep the right fluids on the shell. Also is the cover the same as the previous solid axle corporate 9 1/4" rear end.
 
#3 ·
So there is no way to know until I pull the cover off. The steallarship said they think it's without elsd based on the vin codes.
 
#5 · (Edited)
Don't need to pull cover, just get under car and look for the electric motor. #5 is the electric motor that controls the limited slip. Rear axles without limited slip will not have that motor. Drive shaft connects to the cross near the bottom left of rear end in figure.

The motor would be on the outside of the case between the drive shaft and the drivers side axle.

You can ask Jeep customer service for a build sheet for your VIN, and it will indicate the ELSD if so equipped. The build sheet list what was actually put on the car.
 
#6 ·
Yep. Got under the car last night. No electric motor on the driver-side. So I got me an open rear end. I'm defiantly not "Trail Rated" by any means. Also upon inspection I cant figure for the life of me how to pull the diff cover off without dropping the whole rear end. Is it possible that the Allen keyed plugs on the sides of the case are drain plugs? And there is a fill location somewhere else? Maybe I will just have to resort to my stellarship doing this service when the time come.
 
#8 ·
Yeah I think your right. I called the dealer and the parts counter pulled the build sheet and didn't see ELSD and then proceeded to say "Oh yeah, its not even a 4wd". He did say its a 122mm axle which the parts manual clearly shows no ELSD. How does one even service these differentials?
 
#9 ·
There are two allen head plugs in the case. Top one (higher up) is fill and bottom one is drain. There are torque specs in the manual that will tell you how much torque is required to re-install them. Not hard to do, get it warmed up good, pull upper plug, then lower plug and allow to drain as long as your patience can hold out. Re-install lower plug, (torque to proper spec) and fill through upper. Re-install upper plug and torque to spec. Done....(pg 509)

Rear Axle Fluid Level Check​
The rear axle oil level needs to be between 1/8 in (3 mm)
below the bottom of the fill hole and the bottom of the fill
hole.
The rear axle fill and drain plugs should be tightened to
22 to 29 ft lbs (30 to 40 N·m) on axles with aluminum
housings. The rear axle fill and drain plugs should be
tightened to 22 to 52 ft lbs (30 to 70 N·m) on axles with
cast iron housings.​
CAUTION!​
Do not over tighten the plugs as it could damage then
and cause them to leak.
Selection of Lubricant​
Use only the manufacturer’s recommended fluid. Refer
to “Fluids, Lubricants, and Genuine Parts” in “Maintaining
Your Vehicle” for further information.​

 
#10 ·
Thank you everyone. I feel reassured that this will be a fairly straight forward maintenance. My service adviser said they use 75W-140 for all diffs. That seems crazy when the book says 75W-85 for this application.
 
#11 · (Edited)
ALWAYS go by what's in the manual, your "service adviser" is just being lazy or can't read....

Directly from the manual (the "adviser" didn't read past the first line) The first one is for front/rear on V6 and front on V8. Perhaps they need a course in remedial reading....
Axle Differential (Front-Rear) MOPAR Synthetic Gear & Axle Lubricant SAE 75W-140 (API-GL5) or equivalent with friction modifier additive.

Axle Differential (Rear) – 5.7L Engine With Electronic Limited-Slip Differential (ELSD)
MOPAR Synthetic Gear & Axle Lubricant SAE 75W-90 (API-GL5) or equivalent.

Axle Differential (Rear) – 5.7L Engine Without Electronic Limited-Slip Differential (ELSD)
MOPAR Synthetic Gear & Axle Lubricant SAE 75W-85 (API-GL5) or equivalent.
This is yet another reason why I hesitate to let any dealership idiot touch my cars. Hopefully the mechanic has at least 1st grade reading skills.
 
#12 ·
I could only find redline gear oil in that grade with a gl-5 cert. I really wish Valvoline or Mobile one had this grade. Is there any other options in 75w-85?