Front Differential Fluid

[67Customs]

Quick question.

MY FSM says the front diff requires 80W-90 while the owners manual says it requires 75W-140.

Which is correct?

2005 Limited with 3.7, Auto and Selec-Trac (if any of that makes a difference).

 

[JJsKJ]

Split the difference and run 75w110. I run it in all diffs in all 4 of my Jeeps. Different years specified different weights. Guess the mfg couldn't make up their mind.

 

[LibertyTC]

Regional Variety Flavors

I do not know what region you are from, however most would say just use GL5-75-140 front and rear diffs. This offers good protection if it is warm out, lots of highway, and you wheel often or trailer.
Flavor 2 :
In the great white North though if it is cold and below freezing where I mainly use the Kj only for winter, I use GL5 synthetic 75W-90 front and rear, as this makes it less sluggish when it is -20 ,and the diffs have a hard time staying warm with the thicker "hot" 140 in there. Better fuel economy with 90W when it is cold too, less resistance.

 

[67Customs]

Split the difference and run 75w110. I run it in all diffs in all 4 of my Jeeps. Different years specified different weights. Guess the mfg couldn't make up their mind.

I just want to know why the descrepetency and which is right. I am currently running 75W-140 since I had the manual and not the FSM when I first changed my diff fluid.

I do not know what region you are from, however most would say just use GL5-75-140 front and rear diffs. This offers good protection if it is warm out, lots of highway, and you wheel often or trailer.
Flavor 2 :
In the great white North though if it is cold and below freezing where I mainly use the Kj only for winter, I use GL5 synthetic 75W-90 front and rear, as this makes it less sluggish when it is -20 ,and the diffs have a hard time staying warm with the thicker "hot" 140 in there. Better fuel economy with 90W when it is cold too, less resistance.

Western NC. We get a wide range of weather. I do a good share of towing and off-roading, so I think 75W-140 is fine. I'm just curious as to why the two are so different.

 

[JeepJeepster]

Ive always ran 75w-140 in all of our Jeeps. Never had a diff go bad out of the 8 of them.

 

[JJsKJ]

I just want to know why the descrepetency and which is right. I am currently running 75W-140 since I had the manual and not the FSM when I first changed my diff fluid.


Western NC. We get a wide range of weather. I do a good share of towing and off-roading, so I think 75W-140 is fine. I'm just curious as to why the two are so different.

Typical mistake by the MFG. You know you can trust everything they say about your vehicle.