ah ok makes sense now... thanks hydra... next diff flush i do im putting in mobile one 80w-90

 

Should be just fine, but it is a heavier weight then what you should be using. The 1998 9.25 should use 80W-90 or 75W-90 (fully synthetic). A 75W-140 is a little heavy on the hot side but should be fine, however I would use it as a clean out and replace with the correct lubricant later.

No as Fire stated. However there is no LSD in a non LSD carrier, the reason for the extra friction modifier (because gear oil already has some friction modifiers in it, just not enough for LSD clutch packs) is the clutch packs in the LSD creates a lot of heat and friction, so the extra modifier is needed to lubricate the clutches. It will not hurt your lubricant values in non LSD models.

Surely, what I am talking about is the oil base. See all oils and greases are made from the same oil base, it's just the added additives that make their weight and values. Now in a conventional oil the company separates the oil base from the crude. It is a regular base oil.

To make a Fully Synthetic the a company takes that conventional base oil and continues to refine it further to break it down even more (clean it up). A Fully Synthetic oil was that "fully" broken down oil base with additives. Then Mobil One took some companies to court and a federal judge rendered the name "Fully Synthetic" as either a fully broken down, or manufactured for a certain amount of time. THe reason Mobil One took them to court was because they were not "Fully" breaking it down, instead they were just breaking it down for a certain amount of time. This breaking down for a timeline is called a "Hydra-Cracked" oil base. And a Poly oil base (Polyalphaolefin base) is a "fully" broken down oil base to 2 molecules. Also some of the additives like detergents are more or better than conventional, that's why they clean up an engine.

See there is a huge difference. So for a "Blend" they take some from whatever type synthetic they make and some regular conventional to make a "Blend". You see they just contaminated a synthetic base with a conventional rendered base. You still have the crap from the conventional in there and that "contaminates" the synthetic......It's a simple marketing ploy.

Now Mobil One's Fully Synthetic engine oil / gear oil is a Polyalphaolefin base (poly) base. You have to read the MSDS sheets to see what the manufacture uses.

Looks like your "Konklin, 75W-140 full synthetic" is actually Conklin 80W-140 Fully Synthetic, however it is still a Hydro-Crack. Got this off the company web site:

By combining synthetic base oil with premium Poly Alpha Olefin (PAO) synthetic oil, the unique formulation.
http://www.conklin.com/site/agrotrak/index1.cfm
http://www.conklin.com/library/index.cfm?search=MSDS

 

Here is some good info: http://en.wikipedia.org/wiki/Synthetic_oil

 

Ok so I misspelled it, I will probably change it when I do the front diff and transfer case this winter to a 80W-90 or 75W-90 which ever I can find in full synthetic.

 

The Full Synthetic is 75W-90, I have never seen 80W-90 in Fully Synthetic.


I would use Mobil One Fully Synthetic LS but that's me and put the whole 8oz bottle from Auto Zone in the rear first then top it off 1/4 inch from the bottom of the fill plug. The reason for a 1/4" below the fill plug is because when it gets hot, and it does, it expands and it won't leak from the fill plug like you see on trucks all the time.

 

I haven't seen it leak YET and I filled it all the way and did quite a bit of towing with it this summer. Might have to chalk it up to having a heavier weight in it.

 

You know.....You'de never learn these things if you didn't find a place like this.....I know a ton of guys around here that wait for the sales on the blended oil and swear that they're using something "Just as good as that waste of money you're buying" (yup said it too me this weekend)..I won't even explain it to poeple like that...now that I understand the process a little better I'll just have a laugh and watch them buy contaminated oil.....what a lousy market scheme.

BTW, it might be my imagination but after the gearoil change I swear things just feel smoother.The oil I dumped didn't look spent so I know the P/O had it changed but I don't think they used additive....it just feels like the Mobile1 has a noticable effect, like it rolls along easier....might just be the OCD kickin in though....

 

I always have noticed a difference after doing the diff's and installing Mobil One FS LS, it always runs smoother and less noise.

 

had to explain to my girlfriends sister why you dont run synthetic oil on a real old car and what it does... (she drives a 86 honda accord, she took it to firestone and now it leaks like a siv)

 

Next time ask one of them to explain why they think their blend is better?

I found that usually throws them off. lol