Help w/Diff Oil Choice

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Oct 29, 2004
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Greetings All, I just bought a used 2016 Jeep Wrangler (Dana 44 Rear Diff with Trac-Lok) with 42K Miles on it. Since I am not certain of the maintenance history I have decided to change some of the fluids. For the differentials the owner's manual specs Mopar Gear & Axle 80w-90 GL-5 (I will not be towing). However, the Mopar fluids are very expensive here and the parts guy at the dealer actually told me to go to a local parts store to purchase fluids as the dealer prices are outrageous (honest guy). At this point I already have the Mopar LS additive and I am only looking for Diff oil. A wide selection of Ravenol oils are available to me from a local parts store, so I used Ravenol's "oil finder" to see what product the company would recommended for the Jeep. To my surprise the top recommendation in their listing is a semi-synthetic TGO 75w-90, and number two in the list is a synthetic VSG 75w-90 that appears (to me at least) to have better specs than their top recommendation. Am I missing something here? Is there a reason why I should use the semi-synthetic TGO over the fully synthetic VSG? Oil specs linked below: Ravenol TGO Semi-Synthetic 75w-90 Ravenol VSG Fully Synthetic 75w-90
 
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The "GL-5" and 80W-90 part is the key. Buy a fluid that matches that. I've seen many fluid manufacturers recommend 75W-90 in applications that originally called for 80W-90. The difference between 75W and 80W is nothing to be concerned with, plus the 75W seems to be only synthetic or synthetic blend.
 
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Originally Posted by Jeffrey
Greetings All, I just bought a used 2016 Jeep Wrangler (Dana 44 Rear Diff with Trac-Lok) with 42K Miles on it. Since I am not certain of the maintenance history I have decided to change some of the fluids. For the differentials the owner's manual specs Mopar Gear & Axle 80w-90 GL-5 (I will not be towing). However, the Mopar fluids are very expensive here and the parts guy at the dealer actually told me to go to a local parts store to purchase fluids as the dealer prices are outrageous (honest guy). At this point I already have the Mopar LS additive and I am only looking for Diff oil. A wide selection of Ravenol oils are available to me from a local parts store, so I used Ravenol's "oil finder" to see what product the company would recommended for the Jeep. To my surprise the top recommendation in their listing is a semi-synthetic TGO 75w-90, and number two in the list is a synthetic VSG 75w-90 that appears (to me at least) to have better specs than their top recommendation. Am I missing something here? Is there a reason why I should use the semi-synthetic TGO over the fully synthetic VSG? Oil specs linked below: Ravenol TGO Semi-Synthetic 75w-90 Ravenol VSG Fully Synthetic 75w-90
In Germany they have fully synthetic & synthetic technology, the latter is dyno based, but upgraded with additives to make it "technologically" synthetic. There are applications where the dyno based oil works better with the additives than a synthetic based oil. Trust what the manufacturer tells you. P.S. I just noticed you live in Germany, so what I said is no news to you. smile
 
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Jeffrey

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Originally Posted by hallstevenson
The "GL-5" and 80W-90 part is the key.
I wondered if the GL rating was the issue for Ravenol: VSG is rated GL-5/GL-4 and the TGO is rated GL-5.
 

Jeffrey

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Originally Posted by Pelican
There are applications where the dyno based oil works better with the additives than a synthetic based oil. Trust what the manufacturer tells you.
This is my first Jeep and I had begun reading Jeep forums last week. Some of the guys there swear by Dino in differentials, claiming that differential builders have "done studies" showing that using conventional oil their diffs run cooler...seems illogical to me, but I am no tribologist nor do I build diffs.
 
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Originally Posted by Jeffrey
TGO is rated GL-5.
Certainly safe to go with that one then
 
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not cheap but prolly one of the best, RedLine Ester based lubricants, either call them or use their web site. i changed all the drivetrain lubes in my new to 2011 nissan frontier SV 28 thou at purchase time last year. i gained at least 3 mpg's + surely better protected cooler running gears!
 
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Originally Posted by Jeffrey
Originally Posted by Pelican
There are applications where the dyno based oil works better with the additives than a synthetic based oil. Trust what the manufacturer tells you.
This is my first Jeep and I had begun reading Jeep forums last week. Some of the guys there swear by Dino in differentials, claiming that differential builders have "done studies" showing that using conventional oil their diffs run cooler...seems illogical to me, but I am no tribologist nor do I build diffs.
Dynatrac specifically for some reason wants people to use conventional. They say as you have heard, that synthetic doesn't cool as well, although I'm not sure where they got their info. Anyway, I have the same vehicle (a 2014) and I just use basic 80w90 and change it about every 40-50k km or so, maybe more if we go into deep water. GL5 is fine for differentials, GL4 means it is also safe for yellow metals but those would only be in a transmission.
 
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Jeffrey

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Originally Posted by Jimmy_Russells
Dynatrac specifically for some reason wants people to use conventional. They say as you have heard, that synthetic doesn't cool as well, although I'm not sure where they got their info. Anyway, I have the same vehicle (a 2014) and I just use basic 80w90 and change it about every 40-50k km or so, maybe more if we go into deep water. GL5 is fine for differentials, GL4 means it is also safe for yellow metals but those would only be in a transmission.
Speaking of GL-4/GL-5, I saw this in the VSG description "suitable for synchronised and non-synchronised manual transmissions" and wondered if there might be some additives for synchronized transmissions in there that my LSD sure simply doesn't need. So I went with the TGO oil that is GL-5 ONLY and will add the Mopar LSD additive. Regarding the synthetic vs Conventional in Diffs argument, the TGO splits the difference here - semi-synthetic.
 
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