Differiental / gear oils... any favorites?

[Steve in Seattle]

Well, on my own ride (1997 Trans Am: dynos 280rwHP, 300FtLbs, on a 7.5" 10-bolt rear... yes, I crushed the diff), the differeintal oil is spec'd by GM as being 80W-90 with a GL-5 rating (whatever that is... any info?).

I just removed the stock Auburn Limited-slip diff (in about 20+ peices) and installed an Eaton Posi (Eaton's name for limited-slip diff, you might remember this from GM's Muscle Car era posi-traction, when Eaton was the GM supplier).

The stronger diff locks up a bit easier on corners than the Auburn unit used to. Should help prevent those 1-wheel burnouts at the strip

Here's the question:
What weight, type, and brand gear lubes does everyone use?
Any info on RedLine vs. Mobil 1 vs. Valvoline?
synthetics vs. mineral?
75W-90 vs. 80W-90 vs. 85W-140?

I putting in 85W-140 on reccomendation from the shop that did the work (now that I've finished the 500+ mile break-in period).

Apparently, the GM Differiental additive isn't needed for the Eaton unit either, just going with a higher-weight oil instead (which isn't the case for the Auburn unit which gets a bit noisier without the 4oz. of additive). Anyone know why?

Is the GM additive a friction modifier or does it serve a different purpose? (i.e. suspension agent? detergent/surfactant?)

 

[Spector]

3000GT VR-4 Twin Turbo 6 spd. Factory fill 75W90 GL4 in transmission and 80W90 GL-5 in rear (AWD) Shifting when cold was terrible.

Went with Amsoil of same weights and it improved slightly. Went with Redline MT-90 in transmission, big difference, shifts much smoother when cold. Many suggest using Redline 50-50 mixture of MTL and MT-90 for even better shifting. MTL is 70W80 weight both a GL-4

Believe there is a diff between GL-4 and 5 and should not use either if not specified norshould they be mixed

 

[UncleS2]

GL-5 is a gear oil grade, but I really can't supply any more details. If had anything that used normal gear oil, I'd use Mystic in it. Made by Cato Oil & Grease Company, OKC, OK. Looks like strawberry snow cone syrup. Years ago, I worked for an oil field trucking co. in OKC. Shop foreman said long before, they went through gearboxes & winch gears like popcorn. A salesman offered a price on the Mystic, they bought it, & decided whenever a truck came in, they'd refill all its gearboxes & winches w/Mystic gear oil. He said that within a few weeks, almost all their gearbox problems disappeared. My old Volvo's trans & diff were doing just fine when I sold it 20 yrs and 200K later!

 

[Steve in Seattle]

Hmmm... I've looked all over the net since this post and most everyone keeps saying Red Line.

Looking at their website, I'm considering the Red Line ShockProof Heavy gear oil to save my 4.11:1 gears now that I'm drag racing more.

Specifically:
80W-140
or
Shockproof Heavy, Shockproof LightWeight

[ June 15, 2002, 05:04 AM: Message edited by: Steve in Seattle ]

 

[Steve in Seattle]

quote:

---

Originally posted by Stuart Hughes:
If had anything that used normal gear oil, I'd use Mystic in it. Made by Cato Oil & Grease Company, OKC, OK. Looks like strawberry snow cone syrup.

---

Hmmm... can't find a website:

CATO OIL AND GREASE COMPANY
PO Box 26868
915 N, Martin Luther King Boulevard
Oklahoma City, Oklahoma
United States, 73126
Fax: 405-270-6317
Toll Free: 800-654-8470
Contact: Steve Lindsay, Vice President of Marketing

Cato Oil and Grease
1836 NE 10th St.
9184954000
Oklahoma City, OK 73117-4415
Phone: (405)270-6200
Toll-free: (800)654-8470
Fax: (405)270-6317

Although I can't find a website, it seems like they use the same refinery as Mobil Oil does:
http://www.epa.gov/fedrgstr/EPA-WASTE/2001/October/Day-22/f26530.htm

Here's a retailer for CKO Mystic grease: http://www.marssupply.com/

Just can't find a product spec sheet though

Anyone know CKO's website?

Mac Trucks lists them as an appoved gear oil:
Mystik Synguard SX-7000 SAE 80W-140

[ June 15, 2002, 05:23 AM: Message edited by: Steve in Seattle ]

 

[Al]

I would question the need for additional additives-specifically the "mystic stuff". Sounds like it may be a holdover from bygone days. Just an opinion though. And since it is an ester-there could be a problem with the base oil of mystic-Esters don't like conventional oils as well as PAO's. Just food for thought. Although I don't use the Redline now. Its in my future. Heard lots and lots of good reports about it.

 

[UncleS2]

I have no idea where to look for a spec sheet for the Mystik gear oil.

They also make greases and motor oils. If you're serious about it, might phone the company come Monday, maybe they'll send, fax, or email some spec sheets to you. They don't really go for the home consumer market at all, but for industry & trucking. Sound like any other company we know?

BUT: Jim's Auto Parts here in Lone Star carries the stuff, there's a distributor in Longview, TX, too.

 

[Patman]

Just FYI, the f-bodies that are sold in Canada come with 75w90 gear oil in the rear, while the ones in the US have 80w90. I guess they figure our colder winters neccessitate the thinner fluid. That is what I have always run in all my f-bodies (this one is my third, I had a 95TA and a 98 Formula before this one)

 

[BOBISTHEOILGUY]

Stuart Hughes

quote:

---

They don't really go for the home consumer market at all, but for industry & trucking. Sound like any other company we know?

---

Yeah, Yeah, Yeah Stuart, I hear ya!

I don't know about redline, but I know Schaeffers gear lubes have a strong track record for taking problem gear boxes and keeping them running.

Because of the mo used in the gear lubes, it actually reduces fuel consumption there fore if used in the tranny and rearend you'll see anywhere from 3-5% increase almost near immediatly as well as reduce noise and wear.

Not only that, Schaeffers gear oils when cold will climb straight up an egg beater so to cause it to lubricate the ring and pinion faster where as most gear oils have to rely on the sling method of lubrication back there which causes wear during the first little while until enough speed is rotating the gears causing the oil to sling. This is really predominate in big trucks.

[ June 15, 2002, 06:24 PM: Message edited by: BOBISTHEOILGUY ]

 

[widman]

This forum doesn't leave room for as detailed a response as I could get into, but:
First: GL-5 is a the API gear oil spec, sort of like SL is for gasoline engine oil, but higher is not always better. There are transmissions out there (mostly ZF) that will burn syncronizers with the higher additive (Sulfur/Phosphorous) levels of GL-5.
Most GL-5 Gear Oils provide about 40 to 45 lbs of protection in Timken tests with the Sulfur/Phos. addive Some provide 60 lbs. Most also already have LS additive to allow the clutches to enguage on the limited slip dif.

Second: Don't put 85w140 in it unless you want high wear on all the small tolerance areas, pins, bushings, etc.

Third: If you want what Eaton certifies for 500,000 mile initial fills in their Class 8 truck equipment a 250,000 mile later change intervals with a 750,000 mile warrantee, go for Chevron Delo Gear Lubricant 80w90. The formula is Group II base with Inorganic Borate additives that provide 75 pounds of protection and seriously reduce operating temperatures, increase gas mileage, and reduce wear. I've put it in mountain buses and reduced trans temps 35 degrees C, and have it in my 1 ton 4x4 pickup that has put 100,000 miles of off road driving with 1.8 tons of cargo in the last two years.
I have seen Eaton tests against RoadRanger and other synthetics where it blew them away.
If you want to see some of the results I can email them to you. Drop me a line at [email protected]

 

[BOBISTHEOILGUY]

I can assure you that what you say can apply to many other companies lubricants.

They are not the only company that makes an excellent gear oil and actually there is some that will blow that one away.

Just because a company factory fills with one type of oil, doesn't qualify it as the supreme of all and means nothing as they have to find one to use. This selection could be based on any number of factors but obviously they are going to use one that can pass well enough to keep equipment going.

Question would be how many others did they test against, and do they post all this data. I think you'll find they cannot void any warr offered using that oil with any other oil that meets the same min requirements that they currently use.

There is one company that uses amsoil for their factory fill hydrostats. Interesting though I have several companies that have been using Schaeffers in their hydrostats for longer than I have been around and none have had one go bad as of yet.

There is many reasons that factor in when companies choose factory fill lubricants and one should not jump to any conclusion as to it being the best just based on that.

 

[widman]

Bob, I'm not saying this only because Eaton approves it. I've run several tests myself, and after studying the results of the Borate additive in the Group II stock, I am convinced that for anyone who does more than "normal" driving, there is no comparison to sulfur/phos.

 

[VaderSS]

I can tell you for a fact, that automakers only care about a part not failing till it's out of warranty. The 12 bolt 8.5" rearend on my Impala(and various other GM cars and truck) came from the factory with a defective gasket. With this gasket in place, or the factory replacement, your diff and axles were pretty well guaranteed to be toast, by 60-80k. It was a very well known problem from '93 on, with the first thing you'd do after buying an Impala or other B/D body, was to put a Fel-Pro replacement on. GM did not fix this until last year. They never issued a TSB or made a recall(still has the same part number), since the failures almost always occured out of warranty.

 

[TheLoneRanger]

Isn't it the sulphur/phosphorus additives in the GL-5's, combined with heat, that etches the soft metals (syncros) in trannys? I researched this topic last year before changing my Bronco tranny oil. I indeed was told that the borate in the Chevron Delo did not chemically react with the brass syncros, and was safe to use.

The Delo was not readily available in my area, so I went with a Coastal brand lube. One of their engineers told me that Coastal was safe because of "buffers" that they added. This prevents the sul/phos from reacting with the brass.

 

[MolaKule]

Some years ago, on my infamous '86 Burb 2X4,
I changed the 3:08 gears out for 3.42's and
added an Auburn locking differential, since it
was not a 4X4 and I needed extra traction for
wood hauling.

The differential people suggested Pennzoil
80W90 and the GM posy additive. Well, every 18 months I was replacing wheel and pinion bearings
until I switched to Amsoil 75W140. Its been 6 years with no bearing failures. The diff people
theorized that somehow the Auburn unit was shearing the heck out of the fluid and only a synthetic 75W140 could cure the problem, which it did.

 

[Bror Jace]

As I have stated before, I spoke to a Toyota Atlantic racer who used Red Line gear oil in his Ralt's Staffs gearbox and he was getting a lot of wear. Don't know which weight, etc ...

He was griping about this and another racer recommended he try Synergen's Syngear II racing gear lubricant:

http://www.synergynracing.com/products/syngearll.html

He tried it with supposedly excellent results. BUT, he's sticking with Red Line for the motor as he doesn't want to experiment with what already works well in his $30,000 motor.

They have an 800 number if you have any questions:

(800) 456-7665

 

[widman]

LoneRanger- yes, the buffers help. That is the difference in a lot of Sulfur/Phos. products. But nothing compares to Borate. I have a plant where they used to use a Sulfur/Phos. with buffers and had 700 ppm of wear metals with oil changes every 2600 hours. They now have 5200 hours on a Borate/Group II product with 7 ppm. They will probably change out at the end of the year 10,000 to 11,000 hours. They saved 300 man hours of labor in repairs after the season, and reduced their oil use from 2,900 gal per year to 1,100 gallons every two years. Gears are running 11 C cooler.

 

[sprintman]

Steve, I know never to use GL5 if GL4 mandated. i've just Redlined my Subaru outback (eng/trans/diff) and a big difference in trans feel especially cold. If racing Shockproof could be the way to go IMHO.