please tell me if I am on the right track or not!!!!!

[James S]

Hey There,

I would like to run my list of fluids, [which I use year round], passed you, if I could. Please offer recommendations if I am using incorrect ones. Thanks for your help, as always!
Oil: Mobil Delvac1 synthetic, 5w40
Transmission AND Transfer case fluid, Mobil1 synthetic, Dexron III automatic transmission fluid
Front AND Rear differentials, Mobil1 75W90 synthetic, gear oil
Are these good?????? I am a cabinet maker by trade. My load varies from day to day. I live in Edmonton Alberta Canada, and have a GMC Sierra 2500HD, SLT, Crew cab, long-box, four by four. I do LITE towing, but inconsistantly, and my load varies. The heaviest I have towed is four-thousand pounds. It can be just me and the tool boxes and Leer122 canopy, one day, or, I have also hauled several twenty-five hundred pound lifts of Melamine in the bed of the truck other days. [hence getting the 2500HD] I am amazed with the truck, so want to take care of it. I have read about Transynd for the tranny and transfer case. How is the Mobil1, compared to it? Can I use it, instead of Transynd? If no, how come? The same for the diff fluid???? Thanks again, all of you.

James S
PS, I forgot to mention, I use Racor fuel filters, Amsoil air filter, AC Delco oil filters, and the Super Magnetic, oil drain plug. Anything else or different to use?

[ 07-09-2003, 08:13 PM: Message edited by: James S ]

[WhiteDuramax]

I was thinking that one of the differentials took 80/90 and the other 75/90 but I could be wrong. Dont think it would hurt anything the way you have it.

[dmaxalliTech]

James, sounds like your on the right track. Mobil 1 is a very good product. The amsoil atf is a good alternative to the Transynd which is a bit pricey. Mobil gear lube is more economical then the oem stuff, just make sure its got a GL-5 rating and your fine. The only thing you didnt mention is your change intervals. I assume your right on...

[mackin]

The amsoil atf is a good alternative to the Transynd which is a bit pricey.I dunno about that ..... Seems the Amsoil might not have the up to snuff friction additives .....There was quite the discussion a year back on this ...Try a search .....

I will add the average Joe (power wise)might not find out so soon ..... I am going back to Tranysnd have a 5 gallon pale just a waiting my attention ..... Running Mobil 1 syn now ,but time for a change 25K of hard riding .....

Mac ;)

[dmaxalliTech]

Mackin, I am not sure on the make up of the Amsoil, I assume its cheaper? Your prolly right though, since Transynd was made to Allison specs

[DmaxMaverick]

ANY of the synthetic Dexron III ATF's are far and away better than ANY of the dino's. Some applications may not use the potential, such as never towing or never getting the temps up. Amsoil, or any other brand for that matter, may not be "as good" as Transynd, but is an improvement over the OEM fill. I've been running the synthetic "brand X" for over 50K in my Allison. I don't baby my ride, empty or towing with a GCW of over 20K. There is a definate improvement over the OEM dino stuff. I also use it for the power steering/brake system. It is much quieter under strain than the OEM PS fluid. Stays cleaner, too. Seems like it holds pressure better also (less pedal/steering wheel effort).

I recall some time back a "myth" about running synthetic motor oil in Harley Davidsons. The "myth" was that synthetic was too slippery for engines with roller bearings, preventing them from rolling. Well, if the stuff is not allowing enough friction to roll the bearings, it is not allowing enough friction to cause heat or wear. That argument is lost before it gets out of the gate.

With that said, I don't think that the ATF, of any brand, is "overengineered". Lube oil companies strive to make a "more slippery" oil. I don't think the companies would knowingly produce a product that was too slippery for a given application. One major difference between Dexron and Mercon is its lubrocity values. Amsoil ATF (don't know about the others) works well in either application. Not sure about D/C trannies as I have not used it in one.

Amsoil's website, Amsoil ATF spec sheet (http://www.amsoil.com/products/atf.html) , shows recommendations and compatibility for GM, Ford, and Chrysler, among others. It also states TES-295 compliance (Allison's recommendation). I believe that if Allison (or GM) had any reservations about Amsoil's claims, they surely would have denounced its use by now.

I am not at all saying that any one synthetic brand is better than any other. All we have to go on is the manufacturers' claims and personal experience. YMMV.

[ChevysRus]

All well and good, BUT and it's a big Butt.....
While under warranty, I will spend the extra to do it their way, including the darn Grap Juice I just spent too much for. If I have a problem of any kind while under warranty, I don't want to give them any excuses to start questioning the warranty. I know there are laws and stuff, but I don't need the hassle just to save $5-$10 bucks somewhere on fluids and filters etc. Truck goes in, truck gets fixed, no issues about who did what and when.

Now having said that, when the warranty is over....it's a whole new world LOL :D

[Modified]

James S.:
Reference your question "Front AND Rear differentials, Mobil1 75W90 synthetic, gear oil
Are these good?", and WhiteDuramax's statement "I was thinking that one of the differentials took 80/90 and the other 75/90 but I could be wrong."

GM originally recommended 80W90 conventional in the front axil. Recently, they came out with a bullitin about changing this oil to the same as the rear axil, 75W90 synthetic if you live in cold climates, defined as ambient temp <-10 Deg F.
See the link below, which was discussed earlier this year.

http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=7;t=004822