Synthetic Oil and 4x4 differential fluid: Questions

zoso7374 · **Posted:** Tue Mar 03, 2009 2:45 pm

I got a question for some of you gearheads . . .

I made the switch today to synthetic oil, planning to do this for the life of the vehicle (as I did with my last car).

1.) The cost was $69.99 at a place that is usually very cheap . . . seemed high to me, I used to pay $50 at my local mechanic who went out of business, anyone know a common cost for this.

2.) How many miles would you guys recommend between synthetic oil changes (normal wear and tear on my vehicle, mostly highway miles).

3.) The tech at the oil change place recommended (he said JEEP recommended) changing my 4x4 differential fluid every 12K miles ($99.99!!). It has been ten years since I owned a 4WD vehicle and I don't remember ever doing this . . . what are your guys thoughts on this.

4.) He also recommended a fuel injector service for $89.99 . . . I must have had a mark on my head that said "please help me spend $250."

Thanks fellas.

JeepinJarhead03 · **Posted:** Tue Mar 03, 2009 3:02 pm

jeeze, did he recommend dropping your trousers too?

12k mile diff services are in 'my' manual under severe-duty-driving ie: taxi service, extended off roading and lots of towing

i'm sure someone will contradict me here, someone usually does

but if you're using your vehicle mostly on the highway i can't really think of a good reason why you couldn't change it every 60k+ or more and that's more of a let's take a peek and clean off the magnet and make sure nothings getting worn out from normal wear

if you make a habit of really hammering on it on the weekends or your daughter is a ninja-rockkrawler then i'd change it every 12 but do it yourself and save more than half the money, hell, 2 bottles of slippery purple stuff is only 30 bucks, basically 2 for the front 2 for the rear only comes to 60 so thats 30 bucks just to change it, and i'd almost guarantee they aren't using purple or amsoil quality stuff either, whats mobil synth gear lube, 9 bucks a quart?

i'd find a new friggin mechanic

only time i changed the diff lube in my bronco II was either when I had broken something, put in something new, or sunk it in something really soupy

i'll stay away from the synthetic engine oil question, i don't use it, digger or someone would be better off answerin that one

zoso7374 · **Posted:** Tue Mar 03, 2009 3:10 pm

Bronco II!! That was my last 4WD vehicle. 1987 5-speed . . . loved that truck.

And just so I am clear here, this is one of those Jiffy Lube places. Not a mechanic or anyone I would trust. It across the street from my work and we get a 15% discount.

JeepinJarhead03 · **Posted:** Tue Mar 03, 2009 3:15 pm

haha, i had an 87 with an auto

Mike08Liberty · **Posted:** Tue Mar 03, 2009 5:45 pm

Oil change price will vary by brand, oil filter used and if they are using bulk (out of their tank) or package goods. At that price I hope they gave you package goods and you saw them put the Synthetic in.

How long you go on oil changes will have a lot to do with the oil filter used. If you use Mobil 1 Synthetic and then a .99 card board filter .... your not going to be getting a lot of life out of the oil.

People will say I'm crazy and I'm have no idea what I'm doing but I have Mobil 1 Synthetic and a Mobil 1 Extended Performance Filter (M1-209) in my truck right now and I'm at 12,000+ miles since my last change.

Do you know what oil filter they used?

Read some of the stuff here ... I know a lot of people think the Mobil 1 line is not as good as it's made out to be but I will say that my family has been in the oil business for 20 years and have been very close with Mobil and once they merged ExxonMobil for all of the 20 years and I can honestly say that everything they say is true and will vouch any day for their performance and extended oil life.
http://www.mobiloil.com/USA-English/Mot ... epage.aspx

JeepinJarhead03 · **Posted:** Tue Mar 03, 2009 5:59 pm

ive gone some retarted miles on an oil change but i atleast changed my filter during the interval, at the time i was leaking a quart per 1k and it pisst me off to the point where i figured it was changing itself so i kept dumping in oil and changing the filter every 3-6k lol

tools113 · **Posted:** Tue Mar 03, 2009 8:35 pm

Synthetic oil cost between $6.99 to 7.99 a quart, $8.00 to $12.00 for a really good filter.
My self i think those oil change places rip people off. Basiclly charging you 20.00 for labor and supposedly filling all your fluids.

tjkj2002 · **Posted:** Tue Mar 03, 2009 8:47 pm

$6-$7 per QT of synthetic oil,X's 5 qt's = $30-$35 for the oil.Now many places usually do not stock synthetic oil so you got to add markup since they need to out-source it from another place.So $60-$70 for a full synthetic oil change is not bad considering the shop's bulk oil runs them about $0.50-$1 per QT and you still pay like $25-$35 for a standard oil change don't you?

As far as gear oil the good gear oil is topping almost $18 per qt now,you need about 4qts total to do both diffs in the KJ,that's about $80 in oil alone,then you got to pay for the labor of changing it,the rear diff cost more to do in a KJ since you need to pull the cover,clean the cover,and then seal it back up.The front diff in the KJ has a drain plug.So $100 for a each diff service with synthetic oil is also not bad.

You got to remember that you do have to pay labor,we mechanics that are on flat rate will not do work for free,we have to pay bills also.If you work in a service type job that charges by the hour you should know how it is.You all complain about how much it cost to fix your vehicle,just think the about the outrageous price you are paying in labor for construction work,computer work,and lawyers.Were I work I get 0.3 hours to do a diff service,think you can do both diffs correctly in a KJ in 0.6 hours? By the way that is 36mins,anything over that we are loosing money(being paid less).

JeepinJarhead03 · **Posted:** Tue Mar 03, 2009 8:50 pm

i worked briefly at a grease monkey in charlotte nc, which is nothing but a jiffy lube

i made it about 4 weeks before i was sick and tired of tightening oil plugs that had been left loose, taking off old filter gaskets that had stuck and not removed

and it's not like we were that busy, we had 4 racks and 2 inspection bays, it was rare to have stuff on all 4 racks to the point that by the end of the 1st week i was doing stuff on the 4th rack that we technically didn't advertise

stay away from those quickservs, use shell service stations if you need a somewhat quick oil change, most of the shells with service bays are proprietor owned and ran and you can usually find the owner working in the garage, it's good to find the local guys, they need and want your business on a regular basis, vs the quickylube that takes whatever money wherever and however they can get it

tjkj2002 · **Posted:** Tue Mar 03, 2009 9:01 pm

JeepinJarhead03 wrote:

i worked briefly at a grease monkey in charlotte nc, which is nothing but a jiffy lube

i made it about 4 weeks before i was sick and tired of tightening oil plugs that had been left loose, taking off old filter gaskets that had stuck and not removed

and it's not like we were that busy, we had 4 racks and 2 inspection bays, it was rare to have stuff on all 4 racks to the point that by the end of the 1st week i was doing stuff on the 4th rack that we technically didn't advertise

stay away from those quickservs, use shell service stations if you need a somewhat quick oil change, most of the shells with service bays are proprietor owned and ran and you can usually find the owner working in the garage, it's good to find the local guys, they need and want your business on a regular basis, vs the quickylube that takes whatever money wherever and however they can get it

Yeah stay away from jiffylube and wally world for a oil change.I work for Firestone,I am not a lube tech,I only do oil changes when I'm low on diags and major work,or if it's part of the work(IE oil pan gaskets,intake gaskets).If there is a "oil out" and I was the last person to change the oil,I'm fired.You bet your stupid that filter is tight and that drain plug is tight,and then that the oil level is correct when it leaves the shop.Also every tiny oil leak is noted on the work order(1 copy to customer,1 copy remains in the shop).I think they are getting tired of seeing 2-3 pages of the littlest things being noted,but hay I'm covering my butt.

JeepinJarhead03 · **Posted:** Tue Mar 03, 2009 9:19 pm

im commin in the night to steal your discount to buy tires for my gfs car lol

tjkj2002 · **Posted:** Tue Mar 03, 2009 9:30 pm

JeepinJarhead03 wrote:

im commin in the night to steal your discount to buy tires for my gfs car lol

Funny thing is I despise Firestone/Bridgestone tires.My discount is only 35% off tires anyways.

JeepinJarhead03 · **Posted:** Tue Mar 03, 2009 9:38 pm

i dont care, the way she drives, it won't matter

for long :lol:

the pirellis on her car have like 75% tread left, and 2 of them have like 3 cans of fixaflat each :roll:

rickm · **Posted:** Wed Mar 04, 2009 5:45 am

The KK calls for 5W20 oil. I use Mobil 1 synthetic, and buy it at Walmart in a 5 quart container for about $26. That makes it $5.25 per quart, quite a bit cheaper than most places for Mobil 1 synthetic. I think the dealer gets over $8 per quart for the synthetic, so I always get it at Walmart and take it to the dealer for the oil change. They have no problem with me doing that, and in fact recommended that I bring them the synthetic oil to save $$.

tools113 · **Posted:** Wed Mar 04, 2009 8:57 am

I am not a fan of Moble 1, in fact if you check the testing against the most popular synthetics you will find that the Standard Moble 1 synthetic ranks almost at the bottom in all catagories.

zoso7374 · **Posted:** Wed Mar 04, 2009 9:52 am

tools113 wrote:

I am not a fan of Moble 1, in fact if you check the testing against the most popular synthetics you will find that the Standard Moble 1 synthetic ranks almost at the bottom in all catagories.

So what do you recommend . . .

tools113 · **Posted:** Wed Mar 04, 2009 10:47 am

Castrol Syntec, Royal Purple, New Castrol Edge

zoso7374 · **Posted:** Wed Mar 04, 2009 12:02 pm

tools113 wrote:

Castrol Syntec, Royal Purple, New Castrol Edge

Can you lead me to any of these oil comparisons on the interwebs?

FL RENNY · **Joined:** Mon Nov 07, 2005 4:30 pm **Posts:** 458

Changed my oil this weekend......$22 for 5 quarts of Penzoil Platinum Synthetic, $5 for Purilator oil filter, total cost $27.......took me 30 minutes to change my oil. I had the same questions about the differential changes for my 4X4 too, my KJ said every 12k miles. I looked it up in my KK manual, and it says 60k if towing and offroading. I tow a boat all summer, and go to the beach every weekend using the 4 wheel drive.....I'll probably change the diff fluids at around 24k-30k miles.......

tools113 · **Posted:** Wed Mar 04, 2009 12:36 pm

http://www.smartsynthetics.com/articles ... esting.htm

Synthetic Oil and 4x4 differential fluid: Questions

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