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Differential fluid?

Jeep 5150 2112

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I have a 2018 JL sport the limited slip differential I cannot get a straight answer on what type of fluid I need to use. The dealer fluid is $50 a quart for 75 w85. I've been told by people I have to use that and an LSD modifier. I've also been told I could just use an 80 w 90 synthetic with an LSD additive. Anybody know the answer. Thank you
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DirtRoad

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Here's what the owner's manual says...

We recommend you use Mopar Gear & Axle Lubricant(SAE 75W85)(API GL-5). Models equipped with Trac-Lok Limited Slip Differential require a friction modifier additive.

So any 75w85 GL5 spec fluid should be ok and you'll need to add limited slip friction modifier.
 

Rhinebeck01

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@Jeep 5150 2112

Lots of good info on the forum regarding diff gear oil change. Search and read read...

Do read through this whole thread, especially..
https://www.jlwranglerforums.com/forum/threads/differential-oil-change.47318/

Best bet is to not buy Mopar branded gear oil, especially from the stealership as it is way overpriced. Do not buy the additive there either. Do not let them do the actual gear oil change either.

Do know though that both Valvoline and Royal Purple have the necessary additive in them....

For someone's JL that needs additive they can use those... if the JL does not not need additive then having the additive does no harm.

Anyway, just use Valvoline or Royal Purple on any stock JL/JLU (whether additive is needed or not) and you are aok.

As for gear oil weight to use.... suggest you use Valvoline or Royal Purple 75w90 Syn. Gear Oil in the front and rear.

IF, if you are towing (have tow package) use Valvoline or Royal Purple 75w140 Syn. Gear Oil in the rear...

YES, you can use other/pricier gear oil...


.
 

DHW

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I have a Rubicon so I can't comment on the FM (although I'm pretty sure your Jeep needs that), but as @Rhinebeck01 stated, I use 75w90 in front and 75w140 in the rear. I went with Amsoil.
 

garyji

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Exactly what Rhinebeck said.

G.
 

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WreckEm711

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@Jeep 5150 2112

As for gear oil weight to use.... suggest you use Valvoline or Royal Purple 75w90 Syn. Gear Oil in the front and rear.

IF, if you are towing (have tow package) use Valvoline or Royal Purple 75w140 Syn. Gear Oil in the rear...
Oops.... So when I changed my diff oil, I saw a generic 75w90 front, 75w140 rear, so that's what I added despite having no tow package, etc.

Any downsides to that, or can I leave it in until the next change? It's been going fine, but I'm a neophyte to this kind of stuff and don't want to cause a longer term problem hah.
 

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Oops.... So when I changed my diff oil, I saw a generic 75w90 front, 75w140 rear, so that's what I added despite having no tow package, etc.

Any downsides to that, or can I leave it in until the next change? It's been going fine, but I'm a neophyte to this kind of stuff and don't want to cause a longer term problem hah.
@WreckEm711

Absolutely no problem running the 75W140 in the rear and you not having the tow package...your not towing.

Your gas mileage will be impacted a tiny bit and no more... Leave it be and then use the 75w90 in the rear next time..

.
 

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@WreckEm711

Absolutely no problem running the 75W140 in the rear and you not having the tow package...your not towing.

Your gas mileage will be impacted a tiny bit and no more... Leave it be and then use the 75w90 in the rear next time..

.
Awesome, always appreciate your insight!
 
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OP

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Thank you for your help with this, my issue is also I bought the lifetime warranty and do not want to void that warranty by using the "wrong fluid". I've heard really bad stories of people voiding their warranty by using the wrong fluid or we're not changing their fluid in a timely manner. There are two different 75w85 fluid the dealer has there is one they say is for the open differential and one for the limited slip and about a $20 price difference per quart. So I need to use the one that does not void my warranty. My other Jeep did not have this warranty issue so it was a royal purple every time which was the best for me. Thank you.
 

SecondTJ

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The $12-15/qt synthetic gear oil (Valvoline, Mobil 1) at Wal-Mart/AutoZone, etc comes with limited slip additive already in it.

$50/qt at the dealer is a waste of good money

I also have the lifetime MaxCare and I’m not worried about putting in 75w90 vs the 75w85. It’s not a big deal
 

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Rhinebeck01

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Thank you for your help with this, my issue is also I bought the lifetime warranty and do not want to void that warranty by using the "wrong fluid". I've heard really bad stories of people voiding their warranty by using the wrong fluid or we're not changing their fluid in a timely manner. There are two different 75w85 fluid the dealer has there is one they say is for the open differential and one for the limited slip and about a $20 price difference per quart. So I need to use the one that does not void my warranty. My other Jeep did not have this warranty issue so it was a royal purple every time which was the best for me. Thank you.
@Jeep 5150 2112
@SecondTJ

I would rather not get into a back and forth in regard to warranty bullchitt.... like, I have to use this fluid or.... ya da, ya da. Reality is they.. FCA/Dealer, cannot dictate brand of fluid you use..

Were it me..... Use a decent product like Valvoline or Royal Purple or Amsoil, etc.. Document your fluid changes. In the documents write that you used Mopar fluids.

IF you ever talk to the dealer, etc. you say you use Mopar fluids and here is my documentation.

Tech, mechanic , whomever when they drain the fluid will not know what the heck is actually in there... If they ask you, say it is Mopar and give the specs... Stick to that.... plausible deniability.
No, you will not be sent to hell for this white lie...

.
 

Rhinebeck01

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@Jeep 5150 2112

Off topic... but you know the 5150 in your forum ID. Do you know what the 5150 label lets call it means?... When I worked in California, I would on occasion deem a patient I evaluated as "5150"....

5150 is the number of the section of the Welfare and Institutions Code, which allows an adult who is experiencing a mental health crisis to be involuntarily detained for a 72- hour psychiatric hospitalization when evaluated to be a danger to others, or to himself or herself, or gravely disabled.

I will deem/label you 5150, if you use Mopar gear oil... :facepalm:
 

Rhinebeck01

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@Jeep 5150 2112
@SecondTJ

I would rather not get into a back and forth in regard to warranty bullchitt.... like, I have to use this fluid or.... ya da, ya da. Reality is they.. FCA/Dealer, cannot dictate brand of fluid you use..

Were it me..... Use a decent product like Valvoline or Royal Purple or Amsoil, etc.. Document your fluid changes. In the documents write that you used Mopar fluids.

IF you ever talk to the dealer, etc. you say you use Mopar fluids and here is my documentation.

Tech, mechanic , whomever when they drain the fluid will not know what the heck is actually in there... If they ask you, say it is Mopar and give the specs... Stick to that.... plausible deniability.
No, you will not be sent to hell for this white lie...

.
Thanks for your response. I would love to do that but I'm going to need receipts for the purchase of the fluid be the correct fluid, then they can deny my claim saying I did not use the right fluid. There are some issues with those limited slip differentials also so odds are at some point I will need that warranty. Thanks
 
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OP

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@Jeep 5150 2112

Off topic... but you know the 5150 in your forum ID. Do you know what the 5150 label lets call it means?... When I worked in California, I would on occasion deem a patient I evaluated as "5150"....

5150 is the number of the section of the Welfare and Institutions Code, which allows an adult who is experiencing a mental health crisis to be involuntarily detained for a 72- hour psychiatric hospitalization when evaluated to be a danger to others, or to himself or herself, or gravely disabled.

I will deem/label you 5150, if you use Mopar gear oil... :facepalm:
Hahah I am a where and I'm trying to avoid the Mopar fluid.
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