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Differential Gear OIL *TSB*

53937 Views 52 Replies 27 Participants Last post by  Bryan K
Hey all,

Just an FYI for anyone planning to change their differential oil.

I had access to 'Alldata' in class tonight, and there were a whole bunch of TSB's in there for the FJ, nothing about bulges though.. So i grabbed a screen shot of this:


At the bottom of the page it said not* under warranty.

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So the differential gear oil should be 75W-85 now? What is the now under warranty referring to?
This is just an oil spec change right? What did you mean by "under warranty"?
Yes this is just a change in the oil to be used next time you change it yourself. I'm sure the dealers knows to do this..(same system they use).


At the very bottom it said "Not under warranty". I assume that meant We can't just drive in there and say i want the new oil for free.
Still runnin Royal in Mine.....
75/90 was for temperature range below a certain temp and straight 90w was for higher temps originally
Well, what is in the pic is all that it said. It was very limited in info.
Well. It looks like not only has Toyota gone to a SYNTHETIC gear oil, but one intended to cover a very wide range of temperatures from extreme cold to very hot

Note that 75W-85 is a very common viscosity range for light duty manual transmissions. It's viscosity is equivalent to the GL-4 SAE 50 spec for heavy duty manual transmissions, and the two are usually interchangeable

Mobil Delvac Synthetic Transmission Fluid 50

A straight SAE 90 is almost impossible to find here in North America, and should *never* be used below -15 C. An SAE 90 is commonly available in many South African nations, the Mid East, India, Australia, Mexico, and many South American and Central American nations

Kind of funny how some of us got flak from the dealership after we mentioned we were using a synthetic gear oil. This makes my decision to use the following gear oil all the much better

Mobil Delvac Synthetic Gear Oil 75W-90, 80W-140
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When you guys change the diff fluid, do you put the diff clutch pack additive in as well?
When you guys change the diff fluid, do you put the diff clutch pack additive in as well?
The FJ has a true mechanical locking rear end, there is no clutch pack involved. No, do not use LSD additive: not needed, no "benefit," extra cost, etc

The heavy duty synthetic lubes I use specifically do *not* use LSD additive. For many HD trucking axles, the use of such additives is prohibited due to less gear tooth protection, increased spalling, etc

This is the shop manual section on the rear axle. Note the shift fork, and sliding splined collar

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Royal Purple 75-90 it is!
The FJ has a true mechanical locking rear end, there is no clutch pack involved. No, do not use LSD additive: not needed, no "benefit," extra cost, etc

The heavy duty synthetic lubes I use specifically do *not* use LSD additive. For many HD trucking axles, the use of such additives is prohibited due to less gear tooth protection, increased spalling, etc

This is the shop manual section on the rear axle. Note the shift fork, and sliding splined collar
I have the LSD rear....4X2.
seems strange to me, that it was 75 90 someone prove to me a .5 difference does anything? i'm with stupid:iamwithstupid:
seems strange to me, that it was 75 90 someone prove to me a .5 difference does anything? i'm with stupid:iamwithstupid:

I would imagine the Toyota Engineers found a reason..
The key here is "synthetic", not just the weight rating change. They most likely decided that the additional protection and temperature reduction provided by synthetic lubricants would help to reduce the occurence of rear diff failures.

I have been using and recommending Redline synthetc lubricants in vehicles for 20+ years, and have yet to see a lube-related failure in any component in all that time. I changed out my FJC soon after I bought it, and when you look at any component that has been run in sythetic oils for any length of time, you can see the difference.

You'll notice more and more OEMs are using synthetics in their transmissions, differentials, and even their engines. This is no accident - it is better for your vehicle.
straight weight 90 called out originally in the manual is, as mentioned above, hard to find in the US. And synthetics do provide a more predictable blend of substances than a fractionated petroleum product. So the change seems reasonable on both accounts.

i do feel slightly better, having already made the swap to multivis synthetics anyway.

So the SAE 90 was breakin oil i guess
I have the LSD rear....4X2.
Again, please refer to the shop manual section I posted, it applies to both 4x4 and 4x2 versions. What Toyota calls "auto LSD" is - in essence - electronic traction control. Engine torque is modulated and the brake is applied to the spinning wheel

http://www.fjcruiserforums.com/foru...e-trac-auto-lsd-atrac-vsc-rear-diff-lock.html

In most light duty applications, the lsd additive shouldn't do any harm. It also has zero benefit. Note that the TSB has separate part numbers for the oil, apparently one oil has the LSD additive and the other does not
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