Differential Oil Replacement - ID'ing

[Rednel]

I'm replacing the oil in my rear differential with 75/140 synthetic. I looked up the build sheet and it appears that I have the 8.25 open (no mention of TransLoc) so from what I can tell, I won't need the friction modifier to be added to this.

If I post a picture can some of you experts confirm by looking at the gear carrier? This is a first time for me

Many thanks!

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[tommudd]

Use dino, not synthetic,
full syn does not last and treat the gears the same as dino

 

[LibertyTC]

Agree with Tom use Dino gear oil.
I use Lucas 80w-90 and for towing 85W-140.
Just to mention if the jeep is ever on a lift, spin the tires forward while in neutral.
A Trac-Loc will have have both tires spin the same direction. (friction modifier required then)
An open carrier will have one tire rotate forward while the other moves in reverse.

 

[DadOSix]

So, that mopar additive —

Is there any harm in using it in a fluid change on an open carrier?

dang! I hate the smell of gear lube!

 

[Rednel]

Thanks for the info and excuse my lack of knowledge here.. I am learning... By dino you mean a non synthetic oil - eg a mineral based oil like this one?

https://lucasoil.com/products/gear-oil/gear-oil/lucas-heavy-duty-85w-140-gear-oil

Thanks

Agree with Tom use Dino gear oil.
I use Lucas 80w-90 and for towing 85W-140.
Just to mention if the jeep is ever on a lift, spin the tires forward while in neutral.
A Trac-Loc will have have both tires spin the same direction. (friction modifier required then)
An open carrier will have one tire rotate forward while the other moves in reverse.

 

[LibertyTC]

That is correct. Dino = a Non synthetic. The Heavy duty Lucas sticks to gears perfectly.
For regular driving use the 80W-90 When towing, Jeep recommends a heavier weight 85W-140 is good stuff.
Service The rear Diff every 30k to keep the rear diff happy and clean.

 

[Rednel]

That is correct. Dino = a Non synthetic. The Heavy duty Lucas sticks to gears perfectly.
For regular driving use the 89W-90 When towing, Jeep recommends a heavier weight 85W-140 is good stuff.
Service The rear Diff every 30k to keep the rear diff happy and clean.

Awesome thanks so much! I'll exchange my bottles of synthetic that I bought yesterday. At least I didn't use them.

 

[LibertyTC]

So, that mopar additive —

Is there any harm in using it in a fluid change on an open carrier?

dang! I hate the smell of gear lube!

Adding the Mopar fiction modifier to an open carrier will not harm the diff in any way.
Having a Trac-Loc without the mopar friction modifier is asking for big trouble ahead.
Ya the smell of gear oil, after enough changes you get use to it..

 

[DadOSix]

Adding the Mopar fiction modifier to an open carrier will not harm the diff in any way.
Having a Trac-Loc without the mopar friction modifier is asking for big trouble ahead.

Great! Gives me a reason to go visit my dealer’s parts guy!

My 04 will be coming home this weekend for oil change and plugs. Might as well be ready for some other maintenance as well.

 

[LibertyTC]

Online you can get your build sheet here by entering your VIN number and look for Trac-Loc mentioned, along with axle information.
https://www.jeepkj.com/threads/build-sheet.64657/
The dealer should be able to tell you if you have an open rear diff or a Trac-Loc rear diff as well I assume.

 

[DadOSix]

Online you can get your build sheet here by entering your VIN number and look for Trac-Loc mentioned, along with axle information.
https://www.jeepkj.com/threads/build-sheet.64657/
The dealer should be able to tell you if you have an open rear diff or a Trac-Loc rear diff as well I assume.

Command trac is listed and a 3.73, so I do not need the additive then, if I understand it correctly.

 

[LibertyTC]

Command Trac Is your Transfer case information.
We are referring to the Rear differential and 3.73 is a gear ratio.
02-05's could have come with either an open differential or a Trac-Lok clutch based locker. All trac-loc diffs need the 4 oz bottle of friction modifier.
Now which rear diff do you actually have?
If there is no mention of a Trac Lok on the build sheet it is probably an open carrier, and no need for a friction modifier.
I'd like to be absolutely certain though. A call to the dealer would not hurt.

 

[DadOSix]

On

Command Trac Is your Transfer case information.
We are referring to the Rear differential and 3.73 is a gear ratio.
02-05's could have come with either an open differential or a Trac-Lok clutch based locker. All trac-loc diffs need the 4 oz bottle of friction modifier.
Now which rear diff do you actually have?
If there is no mention of a Trac Lok on the build sheet it is probably an open carrier, and no need for a friction modifier.
I'd like to be absolutely certain though. A call to the dealer would not hurt.

only other clue is ‘DRAS - Corporate 8.25 rear axle’

quick google tells me open carrier.