Looking For Guidance on Rear Diff Lube Change.

Looking for the reason why I do or do not need a change.
My vehicle is 09. I have heard that sometime between 08 and 09 the design of the diff changed so that you do not need a limited slip additive. Can someone explain about the more recent design change? I do have LSD according to the window sticker. 25,000 miles on the last lube change. For the record, I don't have weird noises coming from the rear, no leaks, nothing bad. Thanks in advance, I don't need tips on how to do it, just info on the design change and how it changes maintenance needs.

 

The earlier diffs used physical clutches to achieve a limited slip effect. These types of diffs require a lubricant with a friction modifier or you won't be able to make smooth turns and the rear end will chatter as it tries to lock up.

The later diffs use an open rear diff (raise one side off the ground and the free side will spin freely and you won't move anywhere.. think of the legal argument in My Cousin Vinny about Alabama mud). The way to achieve limited slip on this type of rear diff is to use a computer to apply slight braking to the rear wheels in order to get out of a rut.

In EITHER case, changing the diff fluid is always a good idea on a maintenance schedule. There is never a reason why you should neglect fluid changes. Just be sure to add friction modifier to yours.

 

But do I need to add the friction modifier to my 09? I thought 09 was a later design. Thanks, just trying to understand this stuff.

 

You could just buy rear diff fluid that has friction modifiers already in it. Those FMs don't hurt anything if you are running an open diff.

 

Your owners manual should offer the correct fluid type in the specs section.

If you don't have one, one of us can link you to a PDF version you can download for free.

 

OP........ Have you considered looking in the Owner's Manual for details on type of fluid, fluid specifications, change interval????

How the design changed is of little matter. WHAT does matter is using the proper fluid and the change interval.

 

The 2005-2008 LSDs used clutch plates for a true mechanical LSD. I think Toyota changed to some type of electronic LSD in 2009, but I didn't do any research to determine what's in the back of those. I concur you can look at the owners manual, but if you want to go full synthetic, you can always search this website, and click the box titled "Find Products For My Vehicle."

Red Line Synthetic Oil (redlineoil.com)

I've been running Red Line Synthetic Oil in all of my manual transmissions and differentials for the last 20 years.

 

I most certainly did check my Owner's Manual. Here is what it says: " Use Toyota approved "Toyota Genuine Differential Gear Oil" or an equivalent of matching quality to satisfy the above specification. Please contact your Toyota Dealer for further details". So the word "equivalent" is open to interpretation. Thus the reason for the information request on this forum. My owner's manual was printed in 2008. A lot of products have come out on the market since then, and going to Advance or Car Quest is a lot more attractive than going to the dealer to buy lubes. Thanks.

 

Thanks, found some info on the Redline site.

 

https://www.tacomaworld.com/threads/changing-differential-fluid-a-step-by-step-how-to.24545/

No modifier

 

Thanks for that write up.

 

Hmmmm....lets see.....according to Ed...and the manual.

75w85 or 75w90 GL-5 as specified in the manual will work just fine.

 

Get under the truck. If your rear diff has a sticker that says LSD then it’s LSD. It only came on Eary sport models like 08. off road was an E locker 8” instead of 8.4”

lsd gear oil means the company already pre mixed in lsd additive

I used lsd 75w140 synthetic instead of 75w90
Many companies offer such products including motul

 

Thanks for 'splaining.

 

09+ used Brake actuated LSD. Pretty sure No modifiers are needed.
If you want to “really sure”, open your drivers door, look on the door sticker for the axle code.
Refer to the link below for Gear ID.
https://www.tacomaworld.com/threads/2005-2016-tacoma-axle-codes.408019/


Open Diff = No Modifiers

The axle code is located here

 

Tru Shooter: That's some good info. Thanks.

 

Don’t be surprised if your code reads “C”.
Which is limited slip. But I’m pretty 2009+ trucks went to Auto-LSD.
Which is technically an open rear, but used the brakes to simulate a mechanical LSD.

@nd4spdbh will probably know.

 

Is the C in the first position of that 4-digit code?

 

It would be the last digit (4th)

1 digit is Ring Gear size
2 & 3 digit is Ratio
4. Is type (open, locker, or lsd)

 

That's good info. Thank you.