Another Gear Oil Question - '05 2wd LSD

[rakent]

Hello all -

I have a 2005 Tundra DC 2wd with a factory limited slip rear. I've been looking through this forum and the threads on gear oil, and while it seems that a number of you are running a synthetic 75w-90 gear oil in your rear, factory limited-slip differentials, I still have some questions:

My manual specs the following for my truck's rear axle: "Hypoid gear oil for limited-slip differential API GL-5" with a "recommended" oil viscosity of "SAE 90" above 0 deg F and "80w-90" below 0 deg F. For trucks with open differentials it recommends "Synthetic oil SAE 75w-140"

From this I would guess that my truck has a conventional straight 90 weight API GL-5 gear oil in it as factory fill.

So here's my question - can anyone shed some light on why Toyota doesn't spec a synthetic gear oil in the limited-slip rear diffs from the factory, and why 75w-90 or 75w-140 are not "recommended" viscosities? The only thing I can come up with is that there is something about a 75w-xxx oil that might impair the operation of the clutches in the LSD, otherwise Toyota would simply spec a 75w-90 or 75w-140 and keep things simple (since these oils are common in the other models). If so, this makes me a little nervous to put Mobil 1 75w-90 gear oil in my truck, which is the oil I would like to use.

I live in Florida where it gets rather warm and run my vehicles hard, so I am very particular about maintenance. If I change the rear axle oil every 15k as recommended in the manual, it is going to be a pain to find a high-quality straight 90w oil without special ordering it.

Any help? If not, can anyone confirm running a synthetic 75w-90 in their factory LSD's with no ill effects?

Thanks.

[MMitsock]

Lots of people have had issues with chatter using synthetic oil in Toyota LSD's. I changed mine using Pennzoil GEARPLUS® SAE 80W-90 GL-5 GEAR LUBRICANT I found at K-Mart. No chatter and not really expensive so you can change it as often as you like.

[Clicker]

I've got an '02 2WD with factory LSD and it's draining as I type. Wanted to run synthetic but my local Mopar guru said no. They use a new GL6 lube and add a friction modifier (3.8oz) from Ford, #CM-19546-A1.
So I stop at the Toyota dealer and ask if they sell an additive for my LSD. He tells me no, the service dept only uses it if the diff makes noise and on top of that it's a GM product!
I have decided to go with dino 80-90W by Warren plus the additive by Ford.

[KLS]

GL-6 is an obsolete spec. http://www.lubrizol.com/ReadyReferen...zgearclass.asp

Most differential gear oils already have the LSD friction modifer in the oil. The label will tell. For example, "Pennzoil Gearplus® SAE 80W-90 GL-5 is a specially formulated gear oil .... Recommended by Pennzoil® for use in hypoid or spiral bevel gear differentials and industrial gear units where API Service GL-5 and SAE 80W or 80W-90 viscosity grades are specified. Especially suited for limited-slip differentials as make-up or refill fluid, and is an excellent replacement fluid for rebuilt limited-slip."

I use Schaeffer syn blend gear oil in my TRD LSD with no added additive, and the differential is smooth. Too much additive will cause the clutches to slip; not enough will cause the clutches to chatter.

A PAO base synthetic gear oil will have higher film strength than petroleum gear oil. I use synthetic (or Schaeffer premium syn blend) in everything with very good results.


Ken

[Muleskinner]

I use Mobile One gear oil in my Tundra LSD and my 01 Dodge 2500 LSD. The Dodge has the tightest LSD I have ever seen. I use the M1 with one squeeze tube of LSD additive in both. At 60,000 miles the Dodge still barks the tires going around tight asphalt corners.

So M1 is not too slippery for an LSD like some folks would have you think. I live in the So CAL high desert where it gets HOT during the summer. If you look at the M1 bottle it states the product is formulated for LSD's.

[Clicker]

Originally Posted by KLS

GL-6 is an obsolete spec. http://www.lubrizol.com/ReadyReferen...zgearclass.asp

Most differential gear oils already have the LSD friction modifer in the oil. The label will tell. For example, "Pennzoil Gearplus® SAE 80W-90 GL-5 is a specially formulated gear oil .... Recommended by Pennzoil® for use in hypoid or spiral bevel gear differentials and industrial gear units where API Service GL-5 and SAE 80W or 80W-90 viscosity grades are specified. Especially suited for limited-slip differentials as make-up or refill fluid, and is an excellent replacement fluid for rebuilt limited-slip."

I use Schaeffer syn blend gear oil in my TRD LSD with no added additive, and the differential is smooth. Too much additive will cause the clutches to slip; not enough will cause the clutches to chatter.

A PAO base synthetic gear oil will have higher film strength than petroleum gear oil. I use synthetic (or Schaeffer premium syn blend) in everything with very good results.


Ken

Heck I bought Schaeffer #267 synthetic blend to run in my OEM (Hino) LSD and the shop owner tells me don't do it. So I guess I'll run the stuff I just put in for a while and switch to the Schaeffers later.
Thanks for the link on the GL specs - looks like they moved away from that spec due to the lack of gear boxes designed with the extreme pinion angles.

[KLS]

Heck I bought Schaeffer #267 synthetic blend to run in my OEM (Hino) LSD and the shop owner tells me don't do it.

The shop owner might be an excellent mechanic, but I doubt that he has been trained in lubricants.

I don't know if you'll get the answer here... info@schaefferoil.com I do know that your Schaeffer rep can ask the factory about using 267 in your differential, and Schaeffer will 100% stand behind their answer. I think it would be an excellent choice for your transmission. It is one of the heaviest duty gear oils available anywhere.


Ken

[tundrabrad]

Originally Posted by MMitsock

Lots of people have had issues with chatter using synthetic oil in Toyota LSD's.

This is true...I put Amsoil 75W-90 and their 'Slip-Lok' additive and still experienced chatter. I cured the problem with the addition of a tube of BG LSII friction modifier. Get it at your Toyota dealer...

I won't be using Amsoil again due to their indifference in resolving the issue...

Brad

[scooter45]

I used Mobil 1 with and LSD friction modifier. I feel that there is too much slip. Does not drive like the factory fill fluid did. I will drain and refill with only Mobil 1 75W-90. We will see what happens.......

[kathyricks]

Originally Posted by scooter45

I used Mobil 1 with and LSD friction modifier. I feel that there is too much slip. Does not drive like the factory fill fluid did. I will drain and refill with only Mobil 1 75W-90. We will see what happens.......

Since straight 90 weight oils are not available (in the USA), use an oil that's closest to it like what MMitsock used: Pennzoil GEARPLUS® SAE 80W-90 GL-5 GEAR LUBRICANT available at t K-Mart, Ace Hardware stores and similar places.

Toyota only wants you to use synthetic (75W-140) in open differentials

[LifeTech]

Originally Posted by kathyricks

Since straight 90 weight oils are not available (in the USA), use an oil that's closest to it like what MMitsock used: Pennzoil GEARPLUS® SAE 80W-90 GL-5 GEAR LUBRICANT available at t K-Mart, Ace Hardware stores and similar places.

Toyota only wants you to use synthetic (75W-140) in open differentials

There will be no issues with using this in a an LS Diff:


Mobil 1 Synthetic Gear Lube LS 75W-140

[kathyricks]

Originally Posted by LifeTech

There will be no issues with using this in a an LS Diff:Mobil 1 Synthetic Gear Lube LS 75W-140

How do you know for sure the Mobil 1 75W-140 will not could cause the same issues as Toyota Synthetic 75W-140 in an open differential? Mobil's advice can't be trusted. Example: Mobil says you can use Mobil 1 synthetic motor oil in any car right off the showroom floor. But a representative from Nippon oil informed us the other day, the Toyota factory fill is a special break in forumulation and using an over-the-counter synthetic from day one could interfere with proper engine breakin.

[LifeTech]

Why can't ExxonMobil be trusted?

Because, they don't represent Toyota and it OE products????

Regarding Factory Oil fill supposedly being a break-in specific oil formulation...

I challenge yu to show me one UOA that indicates what exactly is in that Factory Fill. I Don't believe your hype one bit or it's source.
Nonsense. More Corporate hype.

The only thing different in a factory fill is the engine parts assembly lubes i.e. moly, silicones and others, etc. , that migrate to the original fill... a by-product of engine production.

I imagine yu never did a Factory fill UOA before..

LT

[kathyricks]

Originally Posted by LifeTech

[B]Regarding Factory Oil fill supposedly being a break-in specific oil formulation...
[B][U]I challenge yu to show me one UOA that indicates what exactly is in that Factory Fill.

On the 2007 Tundra forum E90Toay, who works for Nippon Oil - a supplier of the factory fill supplier for Toyota - said the following:

"The factory fill 0W-20 for the 07+ Tundra are fully synthetic. The 0W-20 provided to Toyota at factory fill is a special formula created for Toyota, so it will allow proper break in. If you JUST purchased a new trundra, you probably shouldn't change out the factory 0W-20 for at least 500-1000 miles."

[ddvk]

Since you live in FL, I would put Amsoil 75W110 on the differential -- thicker the better. I think that is the route I am going to take for my differential next time around.