What grade gear oil are you running in your Rubicon?

[smlobx]

I’m coming up on 60k miles and planning on a major service. One of the items on the list is to replace the front and rear differential fluid.

In the rear it specifies 75w-85 (many use 75w-90) but I read that Dana says to use 75w-140 for heavy towing and increased protection.

my truck is usually close to max GVWR and I’d like to protect the drivetrain as much as possible.

Any thoughts? Thanks.

Well I just read the thread below and I’m going with the 75W-140…

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[\/\/0j0]

Yep. 75w-140

 

[White Eagle]

Extra Virgin First Cold Press.

 

[Guns_N_Rosaries]

Make absolutely sure that it has the correct friction modifiers. I had a (what I thought at the time) decent shop do my diffs, and they just used some cheap stuff that burned out my rear limited slip diff clutch.

 

[BCB]

Yup, in full synthetic which I believe is the spec. Better flow and less chance of channeling.

 

[WILDHOBO]

Check with whose gears you have. I have revolution gears and they actually recommended against synthetic. They sell their own oil, specifically for their gears. I used to use 75-140, but now take their recommendation. They recommend either 80w-90 or 85-140, both conventional. They’ve had better thermal protection results with conventional. Per the temps in my area, they recommended 80w-90 for me.

https://revolutiongear.com/revolution-gear-oil-80w-90-quart/?searchid=310957&search_query=Oil

 

[smlobx]

Extra Virgin First Cold Press.

Being Italian this has a certain appeal to me!

 

[smlobx]

Make absolutely sure that it has the correct friction modifiers. I had a (what I thought at the time) decent shop do my diffs, and they just used some cheap stuff that burned out my rear limited slip diff clutch.

The Rubicon does not need any additional friction modifiers.

 

[g2020]

This is the standard advice for any trim level. For Revolution gears, also see the previous reply from @WILDHOBO.

Summary

• The owner's manual recommends SAE 75W-85 for both axles except Sales Code DRZ
• The internal dealer spec sheet recommends SAE 75W-140 for the rear axle when equipped with Trailer Tow Package
• Friction modifier is required for Trac-Lok limited-slip (LS) rear differential
• SAE 75W-140 may be required for both axles on modified vehicles
• SAE 75W-85 offers slightly better fuel economy
• SAE 75W-140 offers greater durability

Opinion

• Use SAE 75W-140 in both axles for severe duty, including trailer towing and/or off-road use

Viscosity Grade

• If you want SAE 75W-140 installed by a dealer, request it
• In practice, some dealers use SAE 75W-90 for both front and rear axles likely because it is less expensive
• Many aftermarket brands offer SAE 75W-90, but not SAE 75W-85
• SAE 75W-90 is an acceptable viscosity grade substitute for SAE 75W-85

Key (for remaining sections)

• Industry standard, material standard(s), viscosity grade

Front Axle

• API GL-5, MS-A0450, SAE 75W-85
• SAE 75W-140 may be required for both axles on modified vehicles

Rear Axle

• Not equipped with Trailer Tow Package and not Sales Code DRZ
  • API GL-5, MS-A0450, SAE 75W-85
• Equipped with Trailer Tow Package or Sales Code DRZ
  • API GL-5, MS-8985, SAE 75W-140
• SAE 75W-140 may be required for both axles on modified vehicles

Rear Axle with Trac-Lok Limited-Slip (LS) Differential

• Not equipped with Trailer Tow Package and not Sales Code DRZ
  • API GL-5, MS-A0450, MS.10111 (friction modifier), SAE 75W-85
• Equipped with Trailer Tow Package or Sales Code DRZ
  • API GL-5, MS-8985, MS.10111 (friction modifier), SAE 75W-140
• SAE 75W-140 may be required for both axles on modified vehicles

Friction modifier

• Friction modifier is required for Trac-Lok limited-slip (LS) rear differential
• MOPAR Synthetic Gear & Axle Lubricant does not include friction modifier; it must be purchased and added separately
• Many reputable aftermarket brands of gear oil include premixed friction modifier
• Friction modifier will not harm the factory-installed front differential

Sales Code

• Sales Code can be obtained from a dealer

 

[Jrgunn5150]

When I put my 4.88's in, I poured the factory oil right back in lol

 

[EZRider]

This is the standard advice for any trim level. For Revolution gears, also see the previous reply from @WILDHOBO.

Summary

• The owner's manual recommends SAE 75W-85 for both axles except Sales Code DRZ
• The internal dealer spec sheet recommends SAE 75W-140 for the rear axle when equipped with Trailer Tow Package
• Friction modifier is required for Trac-Lok limited-slip (LS) rear differential
• SAE 75W-140 may be required for both axles on modified vehicles
• SAE 75W-85 offers slightly better fuel economy
• SAE 75W-140 offers greater durability

Opinion

• Use SAE 75W-140 in both axles for severe duty, including trailer towing and/or off-road use

Viscosity Grade

• If you want SAE 75W-140 installed by a dealer, request it
• In practice, some dealers use SAE 75W-90 for both front and rear axles likely because it is less expensive
• Many aftermarket brands offer SAE 75W-90, but not SAE 75W-85
• SAE 75W-90 is an acceptable viscosity grade substitute for SAE 75W-85

Key (for remaining sections)

• Industry standard, material standard(s), viscosity grade

Front Axle

• API GL-5, MS-A0450, SAE 75W-85
• SAE 75W-140 may be required for both axles on modified vehicles

Rear Axle

• Notequipped with Trailer Tow Package and not Sales Code DRZ
  • API GL-5, MS-A0450, SAE 75W-85
• Equipped with Trailer Tow Packageor Sales Code DRZ
  • API GL-5, MS-8985, SAE 75W-140
• SAE 75W-140 may be required for both axles on modified vehicles

Sales Code

• Sales Code can be obtained from a dealer

Rear Axle with Trac-Lok Limited-Slip (LS) Differential

• Notequipped with Trailer Tow Package and not Sales Code DRZ
  • API GL-5, MS-A0450, MS.10111 (friction modifier), SAE 75W-85
• Equipped with Trailer Tow Packageor Sales Code DRZ
  • API GL-5, MS-8985, MS.10111 (friction modifier), SAE 75W-140
• SAE 75W-140 may be required for both axles on modified vehicles

Friction modifier

• Friction modifier is required for Trac-Lok limited-slip (LS) rear differential
• MOPAR Synthetic Gear & Axle Lubricant does not include friction modifier; it must be purchased and added separately
• Many reputable aftermarket brands of gear oil include premixed friction modifier
• Friction modifier will not harm the factory-installed front differential

This is the standard advice for any trim level. For Revolution gears, also see the previous reply from @WILDHOBO.

Summary

• The owner's manual recommends SAE 75W-85 for both axles except Sales Code DRZ
• The internal dealer spec sheet recommends SAE 75W-140 for the rear axle when equipped with Trailer Tow Package
• Friction modifier is required for Trac-Lok limited-slip (LS) rear differential
• SAE 75W-140 may be required for both axles on modified vehicles
• SAE 75W-85 offers slightly better fuel economy
• SAE 75W-140 offers greater durability

Opinion

• Use SAE 75W-140 in both axles for severe duty, including trailer towing and/or off-road use

Viscosity Grade

• If you want SAE 75W-140 installed by a dealer, request it
• In practice, some dealers use SAE 75W-90 for both front and rear axles likely because it is less expensive
• Many aftermarket brands offer SAE 75W-90, but not SAE 75W-85
• SAE 75W-90 is an acceptable viscosity grade substitute for SAE 75W-85

Key (for remaining sections)

• Industry standard, material standard(s), viscosity grade

Front Axle

• API GL-5, MS-A0450, SAE 75W-85
• SAE 75W-140 may be required for both axles on modified vehicles

Rear Axle

• Notequipped with Trailer Tow Package and not Sales Code DRZ
  • API GL-5, MS-A0450, SAE 75W-85
• Equipped with Trailer Tow Packageor Sales Code DRZ
  • API GL-5, MS-8985, SAE 75W-140
• SAE 75W-140 may be required for both axles on modified vehicles

Sales Code

• Sales Code can be obtained from a dealer

Rear Axle with Trac-Lok Limited-Slip (LS) Differential

• Notequipped with Trailer Tow Package and not Sales Code DRZ
  • API GL-5, MS-A0450, MS.10111 (friction modifier), SAE 75W-85
• Equipped with Trailer Tow Packageor Sales Code DRZ
  • API GL-5, MS-8985, MS.10111 (friction modifier), SAE 75W-140
• SAE 75W-140 may be required for both axles on modified vehicles

Friction modifier

• Friction modifier is required for Trac-Lok limited-slip (LS) rear differential
• MOPAR Synthetic Gear & Axle Lubricant does not include friction modifier; it must be purchased and added separately
• Many reputable aftermarket brands of gear oil include premixed friction modifier
• Friction modifier will not harm the factory-installed front differential

Based on the “internal dealer spec sheet” information, if a Jeep has the “Factory Tow Package” I would assume that the Jeep would have 75W-140 from the factory. Anyone know if that is correct?

 

[gatorboy]

Based on the “internal dealer spec sheet” information, if a Jeep has the “Factory Tow Package” I would assume that the Jeep would have 75W-140 from the factory. Anyone know if that is correct?

All you need to know is Amsoil Severe Gear
75-140. It’s in my 790 hp Airboat gear box with nitrous, no problems. It’s what the gear box manufacturer says, and won’t warranty the gear box without it. Done

 

[gatorboy]

All you need to know is Amsoil Severe Gear
75-140. It’s in my 790 hp Airboat gear box with nitrous, no problems. It’s what the gear box manufacturer says, and won’t warranty the gear box without it. Done

It’s also in my diffs in my Mojave

 

[Jteakus]

I did Amsoil 75-140 in the rear and Amsoil 75-90 in font.
4.56's and 39's. I don't tow at all.

 

[WILDHOBO]

All you need to know is Amsoil Severe Gear
75-140. It’s in my 790 hp Airboat gear box with nitrous, no problems. It’s what the gear box manufacturer says, and won’t warranty the gear box without it. Done

I won’t put amsoil in anything. No one seems to want to warranty anything with it. It may be good, but not worth the risk for me.

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