First I am going to adress the origional question,I would suggest crawling under your jeep and looking at the tag on your diff cover , that will tell you if it uses sythetic or not. second I am pretty sure your transfer case and trans both use mopar 4 trans fluid, I know they use tranny fluid but wether or not it is that type i am not sure. one thing is certain if it calls for special fluid use it. they do that for a reason. newer transmissions and such are built different than what they was for better fuel economy,or performance. Amsoil does make a multi use trans fluid as well that can be used in all transmissions and transfer cases.other companies make it as well.

now on to the war over synt vs regular. sythetic oil is purely man made not one drop of crude was used to make it.

sythetic blend is the combo of both and we all know regular oil is from crude oil

now on to the benifits
sythetic does not loose its viscosity as quickly hence the 5k+ oil changes thus it is cheaper in the long run if you go by the 3 k 3 month oil change rule used by reg oil. we charge 26 dollars for a regular oil change that is 5 qts with a common filter and 46 for syth with 5 qts common filter. now if you change regular oil every 3 k that is a total of 52 dollars vs 46 on sythetic.that is if you change the sythetic at 6k, alot of our customers go futher.
Another thing about sythetic as was said before it is less effected by the weather.

Bj I know for years you always said use what the manufacturer puts in in the first place, they do it for a reason. wether it is a spark plug air filter or whatever, the same gois for oil. if it calls for a certain weight ,brand,or type use it.

Personally I use a fram filter on both the wifes and my vehicle and amsoil 5w30 in hers and rotella 15w40 in my jeep. I use the sythetic in hers because we bought it new and it needs to last a long time, plus i get a discount where i buy it. i use rotella 15 w 40 because the jeep was abused it is worn and leaks. and i get that at a discount as well. Once I get my new Vehicle I will use sythetic in that as well.

What, another ^@#$%&* testimonial! <img src="/forums/images/graemlins/lol.gif" alt="" /> Curevo, it's been too long. How are you? And, Happy New Year!

Where in dark abyss of NJ did you get all this wonderful information? <img src="/forums/images/graemlins/smile.gif" alt="" /> Are Jeep "transmissions and such" really any different in technology now in the 21st century than we now own from the 80's and 90's? Are you totally sure all engine oils labeled synthetic are completely 100% man-made? Do you think that most owners of cars operated in moderate climates would benefit from following a 7500 mile engine oil drain frequency (more than "3000 mile rule") as practiced in Europe and Japan? Are you sure that synthetic lube oil systems are less prone to condensation in cold climates than dino oil and dino blends? Do you really believe that synthetics can provide greater vehicle engine longevity in a moderate operating climate that a vehicle using regular engine oil in the same operating climate where the owner follows the vehicle manufacturer's oil change frequency recommendation? Do you know if synthetics can protect an engine better than petroleum-based oil during an engine's break-in period? Will you really save money using a synthetic engine oil if you follow your vehicle manufacturer's oil change frequency recommendation? Are you more knowledgeable about proper engine maintenance than the engineers and chemists that provide owners with the manufacturer's maintenance recommendations?
Curevo, your information about engine oils is most likely based on hearsay, not facts ... IMHO! <img src="/forums/images/graemlins/scared.gif" alt="" /> This is why I don't like testimonials from Amsoil promoters and mechanics. You say stuff without stating your source or any proof that what you state is true. If what you say is only what you believe is true, then simply that you think it is true, or your experiences suggests something is true. I know, I know ... I'm being a little tough on you this evening ... But, you did bring up an important issue in regard to engine oil: proper filtration! <img src="/forums/images/graemlins/kewl.gif" alt="" />

This discussion got me thinking back to my sailor days.
On the USS New York City (SSN 696) we ran 90 weight oil for the main engines and turbine generators. Let me see... if i recall about 750 gallons in the sumps for both 750 KW turbine generators and 3000 gallons in the propulsion lube oil sump serving the twin 15,000 HP main steam turbines and reduction gears. That amount once again in the lube oil storage tanks just in case we had to dump and refill everything.
On the boat, one of the nub nuke jobs every midwatch was running the three lube oil purifiers (and cleaning the SOB's) LOP's spun at about 3000 rpm and spun any water or impurities out of the oil (anybody here ever puked a purifier? nevermind). Then it went back in the tank. Oil never was changed unless we went into drydock for an overhaul. Now I know in an internal combustion engine there are some different chemical issues happening in oil, but it made me think back to the good ol' days on the sub, where the oil never went bad, it just got a little dirty.

Now I'm gonna have nightmares for a week.
Cheers
Josh

yes transmissions have changed quite a bit. toyota,honda,chrysler,and a few others use a special low friction formula. the yno longer use the dexron/mercon anymore. just chevy and ford still use it. they actually started the switch in the mid to late 90's( toyota and honda)

as far as information on the oil it is pretty simple, i base it on the thousands of cars i work on in a year. it does seem that the engines that use synt are in a bit of better shape than those with dino oil.Of course that is just based on 3k or 6 k oil changes whichever the case may be ,and general appearance of the head (looking in the oil filler hole) dino oil seems to leave varnish whereas syth does not. also on the chrysler engines with the huge filler holes(like the jeep 3.7) I have seen less condensation with sythetic than reg oil.

as for the rear diffs many newer four wheel drives use a special fluid if it has limited slip, gm and chrysler has been using additives for those for years, until recently. now they use sythetic gear oil in most cases, while some ***** companies still use the special LSD oil. there are alot of things that play in the role of oil changes.Such as temp,driving habits,how often you drive and so on. as a chemist you should know that anything natural breaks down faster than what is created by men. such is the case between the oils,while dino oil degrades,causing varnish,loss of viscosity and so on over time sythetic does not lose its quality as fast. why do you think manufacturers recommend 3k or 3 months whichever comes first on dino oil?

his question was should he use sythetic like jippy lube told him his jeep takes or just regular. i told him to use what the jeep reccomends(which i think is mopar +4 tranny fluid) and toldd him to check the tag on the diff to be sure it uses sythetic. While it won't hurt to use a synthetic in a non synth rear it will harm it if it needs it and you don't use it(like in LSD rears)

Beleave it or not i have looked at quite a few tests,seen pleanty of evidence,and kept up with compairing regular customer cars with one another to see what was working better. sure i took info from what i was told, but i also looked at things with my own eyes and done my own tests. That is how i got my info. by listening to what the experts say,taking mental notes and doing my own research,and testing.The oil i use is the weight the manufacturer reccomends I use regular oil in my jeep because this late in the game after the years of abuse from previouse owners syth is a waste of money. on the other hand since we baught my wifes car new and we treat it with respect I am willing to put syth in it to help it last longer.
as for the break in time on a car you know that is when the car will burn oil and wear the componites a bit, which is how it finally gets sealed properly. as mentioned before dino oil breaks down quicker,the dirtier it gets the worse it gets. sythetic keeps it's integrity longer, thus the metal shavings does not affect it from the break in period like it will regular oil.
several auto manufaturers actually tell you to use sythetic in their cars,and some tell the brand . most german cars tell you to use castrol, certain mercedes tell you to use mobile one as well as chevrolet in their corvettes and chryslers with their hemi's. we have had dealerships tell us if we didn't use what they reccomend that they will void the warrenty. what it really boils down to is use what the manufaturer tells you to use.

Yes filter changes are important as well as you said, i am sure people can argue on brands of filters as well. I am using what I always used,and until fram if fram ever does something wrong continuously i will keep using them.

Fred don't worry about coming down on me hard,I have been here long enough to know you mean the best,and frankly I enjoy having you question my info. it makes me go back to double check and either prove my case,tell you where i am coming from or to realize I made a mistake.This is how we all learn from one anothers knowledge. <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

I know this is a hot topic, but there is no need to "diss" New Jersey. And I mean that.

Hey dudette! Cuervo has been here many years and he knows nobody meant him any harm.. You'll catch on after a while..

You are correct however...it is a hot topic.

Sorta reminds me of the COLA heydays.. Many here are not old enough to remember when 7-up, Dr. Pepper. Big Red and many other soft drinks were popular...what happened to them?

Well I'll tell you and make it as short as I can..
Although neither will EVER admit the truth...Coke and Pepsi got together and laid out plans for advertising.. What they did was to sign EVERY major supermarket chain to a discount contract.. The contracts clearly state discounts and advertising for 26 weeks a year. So with Coke having 26 weeks and Pepsi having the other 26 weeks... they effectively put all other cola manufactors out of business..
In a few short years all the others were bought up by the two main suppliers because of the grocery chain contracts..

I liken this to the present advertising of motor oil.. NOBODY knows the real truth! When I am at Jiffylube and ask "what is on sale today?" Even the agent looks at me funny..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

Well, I'm glad no one meant Cuervo any harm. But it is New Jersey I'm concerned about.
Interesting info about the cola.

LOL New jersey is to far gone to worry about now,I was born and lived in Virginia for 27 years. Now im in the process of trying to convence the wife to move to VA. This state is an abyss, an abyss of sex,drugs,violance,filth and so on. absolutly no place to raise a child.Sadly when i went to VA over the holidays the area im from is turning fairly quickly into a mini NJ.I want to get there as soon as I can so I can afford to buy alot of land and build a nice house before everthing is ruined down there.

When i first started here,BJ and Fred got on my nerves until I realized that they are old and just grumpy old men <img src="/forums/images/graemlins/lol.gif" alt="" />. seriously though they do know their stuff and their way of telling it is not politically correct, but screw that anyway.If you get your feelings hurt that easy you don't belong here. they get straight to the point,which may come across as harsh but it isn't ment to be.If I thought for 1 second that they was being rude I would light into them myself.

BJ you had dr pepper in the list of cola's that arn't popular anymore. most of if not all my freinds drink that,and MT dew when they are tired of dr pepper. for some reason they go hand in hand.They also mix well with certain uhmm how should i put this,spirits.

Fred I also forgot to mention that the parts store i get my oil from sells fram and Wix filters,Amsoil and Mobil 1 sythetics, and rotella in the heavy oil like 15 w 40. and I pay cost on those. that is the reason i buy those brands on the oil. as I said I always used fram. I don't know what they sell in regular dino oil in the rest of the ranges.I do however know it is a family owned business with one store only so I have the feeling it is mainly what the owner wants to sell,be it because it is name brand or personal experiance.

BJ, you must be thinking of the Dr. Pepper that is still made with real sugar. I don't think that stuff gets shipped outside of Texas. But Dr. Pepper is still very popular.

Dr. Pepper! The beverage was part of the meltdown! Because of the advertising agreement the Dr. was failing and was purchased by one of the big two... as were the other drinks. In fact there may have bneen an agreement between the two as to who would purchase which other company. Just to keep the price down as the others went down..
Yes the Dr. is still popular but it is because it was purchased and became part of the 26 week advertising ...
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />