....I bought 2 bottles yesterday which cost me over $40 with tax
What kind of gear oil?
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....I bought 2 bottles yesterday which cost me over $40 with tax
A Master ASE certified tech would use what the axle manufacture recommends,not who sold the axle but who actually made it.Amen!
So what would a Master Certified Chrysler, Dodge, Jeep Technicianwavey.gif recommend for the KJ's differentials?
Yep it applies more for engines and anything that uses pressure to keep lubricated.You get better lubrication, less lubricant break down due to wear and heat, and generally speaking, components last longer if synthetic lube is used(this applies more to engines than diffs.)
Synthetic fluids flow better so it does not stick to the gears as good as dino gear oil so not cooling the gears in extreme use(towing and offroad).
Pressure from the government for higher mpg #'s,reason why most new vehicles are speced for 5w-20 engine oil.You will also notice a maintenance schedule that requires diff fluid changes more often when synthetic is recommended,the biggest reason again is higher mpg's for CARB.I have to disagree with you on that point. Every modern CDJ product that has a differential recommends synthetic fluid for heavy use applications. All of the Jeeps, except Compass & Patriot, all of the Dodge Rams recommend this.
Dodge Ram 2500 & 3500, which are used to tow large loads, use a 75w90 synthetic exclusively in the American Axles that they are equipped with. Use of any other lubricant will cause damage.
All of the Jeep products that are used to tow with recommend 75w140.
Now why would such companies as Dana, American Axle, and Chrysler recommend a synthetic lubricant for heavy use applications if it was indeed inferior?
What kind of gear oil?
I have to say that synthetic lubricants are superior to non synthetic. You get better lubrication, less lubricant break down due to wear and heat, and generally speaking, components last longer if synthetic lube is used(this applies more to engines than diffs.)
IMO, it is a safe bet to use whatever the manufacturer recommends. They either design it, test it, and build it, or they provide specifications to a 3rd party and have them manufacture the parts.
I would have to trust what a manufacturer says about their own products than what an aftermarket company had to say about them.
Had a great conversation today with the Amsoil drivetrain fluid product manager. Strangely enough they have been recently approached by "A Company", (that has been discussed in depth in this thread for their dislike of synthetics), about private labeling two current Amsoil gear lubes for use with their off road & performance rear ends. Another air operated locker company is also in the final stages of naming a new Factory Fill for their products.
Also brought up was the fact that the owner of the company who doesn't prefer synthetics in their products, is an Amsoil dealer himself, and runs it exclusively in his own & his son's race vehicles. The Amsoil person who told me this had first hand knowledge of this. He read through this thread today & had some great laughs.
He showed me several test results measuring fluid, case & bearing temps in rear ends, proving to me with out a doubt that Amsoil synthetics are superior in heat reduction. The thought process on the molecular size not picking up heat from the metal is "nonsense". Amsoil's molecular uniformity is what makes it superior. The test results, that Currie & Auburn are basing their research on is nearly two decades old and used a synthetic oil at that time that was not the optimum product at that time, let alone now. Oil technology advances nearly every day. He suggested that any company still advising customers to stay away from synthetics needs to update their research.
If a company was sure that Synthetics were causing them problems, they wouldn't be seeking a private label for an Amsoil product. Now I have no proof to back up the private label claims, but also don't believe that would be made up. I have seen proof of other major companies looking for private label motorcycle & race oils. Mr. Amatuzio is very proud to put his own name on his products & doesn't believe that any of his products should have anything other than his name on them. That I know for a fact.
Hope this will ease the mind of a few of you wanting to run synthetics.
Currie does have a recommended gear lube,they even have it labeled for them but it is more commonally known as Torco and no it is not synthetic.Found an interesting post in another forum pertaining to Dino vs Syn...more like Amsoil vs Currie
http://www.jeepforum.com/forum/showpost.php?p=7261820&postcount=127
The brochures for the liberty say they are OPEN DIFF front and rear, so, Synthetic is just fine. I have read other specs they are LSDs as well, so what actually are they?
ESP(the devil)TrackLok was for 02-05 models, what did they use for 06-07?
Heat issue,the front diff holds about 1qt less fluid and get's very little cooling air like the rear diff get's alot in comparison.It's not from the rear diff is always turning since the front "hubs" are always locked in the front so the front diff is always turning also,plus Chrysler did not make the front diff,Dana/Spicer did per Chrysler's spec's.Well if synthetic isn't good for LSD, why does Chrysler recommend synthetic (75W-90 or 75W-140) then?
I notice they(Chrysler) recommends dino oil in the front but synthetic in the back...again why?
You know what...screw this(banghead). When I get my KJ, I'm just gonna follow what the owner's manual says. That's what my dad has been doing with is 2000 Durango and 0 issues so far (215 000KMs) pertaining to diffs, tcase, ******, engine. Did the same with his 88 XJ and 12y/302 000KMs later again 0 issues with the powertrain.
I guess if your an enthusiast, an extreme off-roader, than sure you can go off the map with your fluids. But for someone that drives around town and heads to the cottage every weekend, then following the owner's manual recommendations is more than enough.
/thread
As far as LSD you must add a friction modifier that basically makes the gear oil less slippery so it can operate without chatter.