Differential fluid

[Rhinebeck01]

Currently, the M200 is referred to as a Dana 35. Do your research before you spread more misinformation.

Most people even most friggin asshats know either nomenclature is used.

Most ads, articles, etc. list /call it by either or, or both.

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[Lofty]

Hello everyone,

I have a question regarding the fluid to be used in my differential. I have a 2018 wrangler JL 3.6 from what I can tell I have a Dana M200. The manual states I should use 75W85. I also emailed Jeep Customer Care, they also stated that according to my VIN I have a Dana M200 that requires 75W85. This is where the confusion comes in, according to online research and what others have said in the forums the M200 requires 75W140.
So what informations should I go by?

The correct oil for the M200 axle is 75w140. (1.15 Liters)

 

[Gunfighter]

Well, after consideration...decided to just go 75W-140 all around. Changed out the 75W-90 in the front yesterday. Could I have waited - sure, but just wanted to be done with it - Having ONE diff fluid for both axles is easier. Have enough oils and fluids, grease, this and that in my garage might as well make a very minor consolidation ?

 

[wreck99]

Well, after consideration...decided to just go 75W-140 all around. Changed out the 75W-90 in the front yesterday. Could I have waited - sure, but just wanted to be done with it - Having ONE diff fluid for both axles is easier. Have enough oils and fluids, grease, this and that in my garage might as well make a very minor consolidation ?

I'd be interested to hear about your experience with 75-140 all around. Gas mileage, performance, etc. Also which brand you went with. I believe I read that Dana recommended 140 on both and Mopar puts the 90 on there for CAFE reasons? Also does yours have the drain plugs? Mine doesn't so I'll have to pull the covers. I still have a ways before I need to change the fluids probably (only 2k miles so far) just doing some homework first.

 

[CarbonSteel]

I'd be interested to hear about your experience with 75-140 all around. Gas mileage, performance, etc. Also which brand you went with. I believe I read that Dana recommended 140 on both and Mopar puts the 90 on there for CAFE reasons? Also does yours have the drain plugs? Mine doesn't so I'll have to pull the covers. I still have a ways before I need to change the fluids probably (only 2k miles so far) just doing some homework first.

100%

In the end, your right foot, a headwind, or a heavier load will have more impact on MPG than a viscosity change ever will. There are so many variables that no owner is going to be able to consistently and accurately measure any MPG change due to oil viscosity.

You need a controlled environment and a lab for that...

 

[azwjowner]

100%

In the end, your right foot, a headwind, or a heavier load will have more impact on MPG than a viscosity change ever will. There are so many variables that no owner is going to be able to consistently and accurately measure any MPG change due to oil viscosity.

You need a controlled environment and a lab for that...

It’s been done: https://archive.epa.gov/nrmrl/archive-etv/web/pdf/03_vs_conoco.pdf

The EPA found a 0.97% improvement in fuel efficiency using 75w90 instead of 75w140 in a 2003 F-150.

Not too shabby. A percent here, a percent there, spec 0w20, etc., and suddenly you’re at 5% and your vehicle gets 21 mpg instead of 20….

 

[CarbonSteel]

It’s been done: https://archive.epa.gov/nrmrl/archive-etv/web/pdf/03_vs_conoco.pdf

The EPA found a 0.97% improvement in fuel efficiency using 75w90 instead of 75w140 in a 2003 F-150.

Not too shabby. A percent here, a percent there, spec 0w20, etc., and suddenly you’re at 5% and your vehicle gets 21 mpg instead of 20….

In a lab under perfect conditions.

0.97% of 18MPG (which many Jeep owners do not see either) is 0.1746 MPG.

You will not see any difference in any reasonable length of time and given the operating temperatures and weaknesses in the Jeep axles, 75W-90 would not be my choice.

 

[Tncdrew]

If running a gear oil that offers less overall protection to gain .97% increase in fuel economy, is the goal, I'd say a Jeep Wrangler wasn't the best choice of purchase.

 

[azwjowner]

In a lab under perfect conditions.

0.97% of 18MPG (which many Jeep owners do not see either) is 0.1746 MPG.

You will not see any difference in any reasonable length of time and given the operating temperatures and weaknesses in the Jeep axles, 75W-90 would not be my choice.

I run 75W-140 for all the reasons you've previously enumerated, and in fact I've switched to Amsoil Severe Gear based on your reports. But just because you won't notice the difference from tank to tank, it still exists. If you were at 18 MPG, after 100,000 miles, that's ~54 less gallons of gas, or a savings of perhaps $200. Again, I would rather have the extra protection of the heavier weight oil and $200 over 100,000 miles is a very small amount compared to the other operating costs. But it is a difference. (Multiply by 100,000 Jeeps and now Jeep owners are spending $20 million extra on gas to run thicker oil. If it turns out that their differentials would have survived either way, which is likely the case, that's all wasted money. Let's not kid ourselves -- we are optimizers, obsessed with the longevity of our mechanical devices, while the reality is that changing the gear oil every 50K miles or so is all that the average person does and their axles usually last just fine.)

 

[Gunfighter]

I don't know or care so much about MPG - my last vehicle was an '06 V10 F-250 w/ 4:30's..maybe saw 10 mpg or thereabouts. Here is what I am using for the diff:

 

[CarbonSteel]

But just because you won't notice the difference from tank to tank, it still exists. If you were at 18 MPG, after 100,000 miles, that's ~54 less gallons of gas, or a savings of perhaps $200.

In principle, I agree.

In reality...it is just not going to happen--far too many variables in operating conditions alone that will more than negate any such miniscule savings.

 

[Smokey_The_Rooster]

Reality is , I could care less what a guy/gal does with his JL..

So you could care less meaning you do care some?

FYI: It's "I could not care less". Don't forget the "not" or "couldn't" in that saying. Otherwise, you do care!
Do your homework if you don't believe me. Lol

 

[Smokey_The_Rooster]

? . Most people do not say that correctly. Just here to share a little knowledge, and gain a little knowledge. Glad I could educate.
Smile more, life's too short.

 

[wreck99]

I don't know or care so much about MPG - my last vehicle was an '06 V10 F-250 w/ 4:30's..maybe saw 10 mpg or thereabouts. Here is what I am using for the diff:

Nice! I was between AMSOIL and Valvoline squeeze packs when I did our RAM 1500 last week. First time doing it and good practice for the Jeep haha. I read good reviews from both so figured I couldn't go wrong. I ultimately chose Valvoline because it was more readily available in town and was about 1/2 the cost as AMSOIL. I'm not sure yet which I'll use for my JLUR but at 2400 miles I have plenty of time to decide.

 

[Gunfighter]

Nice! I was between AMSOIL and Valvoline squeeze packs when I did our RAM 1500 last week. First time doing it and good practice for the Jeep haha. I read good reviews from both so figured I couldn't go wrong. I ultimately chose Valvoline because it was more readily available in town and was about 1/2 the cost as AMSOIL. I'm not sure yet which I'll use for my JLUR but at 2400 miles I have plenty of time to decide.

?

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