I have used both regular and syn in the tranny of my trucks and haven't noticed any real difference. Reguardless of which I use I change & flush the tranny every 20k - 25k. The tranny in my 89 GMC Jimmy ( full size ) has over 300k on it and it has seen only std dino atf ( knock on wood ). In my 02 F250 I started using syn in the tranny because I use it to tow our TT alot and a synthetic will hold up to higher temps without breaking down which is what kills most tranny's. JMO

Good info from everybody.... I think I'll pick up a case of Mobil 1 when I go to Costco tonight. I used to use Castrol Syntec in my '90 Integra which after 120K miles never burned an ounce of oil, those were the days. I've switched to using Syntec Blend in my Rodeo when I saw $7 evaporating from my wallet every 1000 miles. Hopefully the Mobil 1 gives me enough peace-of-mind to keep buying it.

About those additives, I have used Prolong in the past and would believe it has a positive effect on my engines, perhaps saved me tons of $$$ once. Since having this Rodeo, and its oil consuming tendencies, I have stopped putting it in. Does anybody know of any objective articles on the subject of additives? I anticipate just switching to the Mobil 1 will justify not putting anymore Prolong in the case.... oooh , but that gold box is just so spiffy <img src="/forums/images/graemlins/notooth.gif" alt="" />

From the same info I have saved, wether it is true or not, why spend $20-30 just for an addative for your oil? Here it is:

"Chlorine derivitaves and other chlorinated solvents are a great lubricant and were used for many years in motor oil before the destructive effcts were discovered.

When the chlorine from the lubricant combines with the hydrogen left over from incomplete combustion and the oxygen, these three things (and others) form HCL...hydro-chloric acid. Very bad for rings and bearings and such.

If left in the engine for extended intervals, creates a lot of damage.

Now...most engine treatments don't reveal thier 'secret' ingredients ('proprietary information' and all that jazz). A few are known to have excessive amounts of chlorinated solvents: Dura-Lube (the worst offender), Resur (a newer russian product),and the now-defunct STP engine treatment.

Rarely can any benifits ever be found with these additives, but even if there are benifits, they are always very short lived. Certainly lasting no longer than the length of the oil change interval, or possibly two. (50,000 miles with a single treatment? Only a fantasy, I'm afraid). They are certainly NOT cost effective.
'Marvel Mystery Oil' is considered to be an oil treatment, not an engine treatment. Some, but not all, oil treatments are good.
'MMO' is just plain and pure light-weight mineral oil. It's higher solvency ratio tends to help clean and lubricate lifters, promotes the removal by combustion of light carbon deposits in the upper cylinder area, and will even clean and (somewhat) lubricate fuel injectors.
A can in the gas tank once a month tends to help, as does a can installed with a fresh oil change if you have been guilty of not-frequent-enough oil changes.
Plus, it's cheap!
Z-Max, by the way, is nothing more than several bottles of plain old mineral oil, with a minute amount of food-grade dye added to give it a unique color. It certainly doesn't have anything called 'Linkite' in it, whatever the hell that is. What you can get from Z-Max for $50+ you can get from MMO for around $5.00.
Skip the engine treatments, change the oil and filter every 3,000 miles and you will save money and have a much longer lasting engine."

I find it hard to take this high tech advice from someone who has Sponge Bob as their Avatar. What is your area of expertise in oil? What do you do for a living?

I'm not saying I disagree with you, cause I don't recommend any additives either. I'm just curious where you get your information.

As someone who is "infamous" for asking for REPUTIBLE sources to link to, I have to tenativly agree: I'd like to see sources. There's more claims about oil than there is oil out there.

Even in this post, I've still seen nothing that says $20 Mobile 1 is twice as good at protecting than $11 Wal-Mart full synthetic except for Mobile's advertising campaign. Their own web page has nothing about it:
Mobile Oil Info

Before I'm bashed, I do have Mobile 1 synthetic in my new Rodeo. (For now!) But in my 1993, 167k mile 2.6 Amigo, it's Dino-oil all the way. And for the last 67k it's been Wal-Mart Cheap-o Dino-oil at that, with 5k-6k on oil changes. For normal drivers (high-stress applications aren't an every-week thing), synthetic really doesn't seem to have any advantages over Dino oil. I don't mind saving $15/5 quarts over a 15 year lifetime that I'm going to get of the Amigo. (And a new car is nice after 15 years). $20 Synthetic seems (as there's no proof at all) only marginally better than $11 synthetic, especially if it's the same base stocks and have 99.5% of the same goverment-mandated additaves for the star-stamp.

I'm factoring the above posts and info against the July 1996 Consumers Reports oil test. They took 75 new NYC taxicabs and measured all the "high wear" areas in the engine. They used regular and synthetic oil (including Mobile 1), 3k and 6k changes. Summary: No noticible differences in wear in 3k or 6k chanes. Barely noticeable (with micrometer) difference between Mobile 1 synthetic and regular oil

(Lots of idleing time; really tough on an engine--see your Isuzu owners manual; it defines heavy towing and extended idling as the heavy-duty operations that require more frequent servicing)
Most of CR article at: http://www.scuderiaciriani.com/rx7/oil.html
(further googling could probably turn up the whole thing)

Well in Texas you may not care, but in Minnesota it is nice to have oil that flows at -20 degrees, rather than acting like pudding.

I remember a racing team saying that they could get several races between rebuilds with Mobil One, whereas with dino they had to rebuild after every race. Of course, that is extreme duty, perhaps us civilians never reach that level of performance.

All I know is I have never had an engine burn appreciable amounts of oil in the 20 years I have been using Mobil One.

It's old news and maybe just marketing bull, but Mobil used to claim that the Callaway Turbo Corvette and the Porsche 911 Turbo both came from the factory with Mobil 1 and stipulated it's use in the Owner's manual. I dont know if that means diddly or not .............. I dont think you'd catch Porsche recommending the use of Wal Mart oil .......... <img src="/forums/images/graemlins/lol.gif" alt="" />

this is bad, very bad advertising for Mobile1... Porsche customers can afford to rebuild their engines every 10K miles, so it means they do not care about oil and they can put any junk oil like Mobil1 in their things <img src="/forums/images/graemlins/smile.gif" alt="" />

I use Mobil1 myself but I found this advertizing quite a stupid marketing. I do not care whatever Porsche users put in their special vehicles, I have a truck.

Oleg

If I wasn't clear, I wasn't stating Regular vs Synthetic oil, I'm going to continue to use synthetic in the new car even if I'm not certain of the benefit. My real question is what brand. Some of the stocks info was good.

Extended operation above 90deg and below 0 degF--especially starting it once or twice a day--qualifies for the alternate maintenance info. My manual is in the car, but I'm pretty certain those were the temp breakdowns; I know the 90degF is right. (Rear differential actually goes to 140wt if you're constantly above 50degF and running above 90degF)

If you tow a load of spare parts from Phoenix in the summer up to BigSwede and stay the winter, I'd change all the fluids before the first frost. <img src="/forums/images/graemlins/smile.gif" alt="" />

/rant
Wow that was a little uncalled for now wasn't it? <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> I don't judge you or your knowledge through your avatar. What do I do for a living? I am a computer nerd pretty much. I work for a local ISP, so I don't work with oil all day. I just added information that I have heard, that works for me over the years, and the amsoil information from pretty much 1 source. I am shocked that that came from a fellow Isuzu board member.
/endrant

All I said is that it is some information that I found. Is it 100% true? Maybe, or it might not be. I do have information on many of the things, to back it up. Oil Filter information and a few other things that aren't quite what I was looking for but good information.

http://fordvschevy.com/forum/showth...amp;t=47754&page=2&pp=30
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=4;t=000275
http://www.bmworlando.com/pages/services/tech/faq/syn-oil.htm
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000359
http://www.vtr.org/maintain/oil-overview.html
http://forums.corvetteforum.com/archive/index.php/t-859567.html


Oil Filter
http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html
http://www.scuderiaciriani.com/rx7/oil_filter_study/

Bottom line, is honestly do what you think is best for your rig, don't take advise from a spongbob.