differential fluid change question

[montana4runner]

I've been getting the needed maintenance done on my 2000 4Runner, purchased a year or so ago, and am getting ready to change out the differential and transfer case oil. During a research session, I found that Toyota apparently had issued a TSB for early 2000's Tundra's and Sequoia's concerning synthetic gear oil. "The TSB says "Toyota Genuine Synthetic Differential Gear Oil (P/N 00289–75140) CANNOT be used in 2000–2002 Tundra vehicles and 2001–2002 Sequoia vehicles. The rear axle oil seals are not compatible and will leak if synthetic differential gear oils are used in these vehicles." (TSB DL003-03) I realize that this isn't addressing our 4Runners, but I was wondering if anyone here has noticed a correlation between changing to synthetic gear oil and subsequently experiencing axle seal failure shortly thereafter? I like synthetics, but I'd rather not deal with leaking seals if there is a evidence that this might be the case. My Runner has performed admirably with dino in the boxes for 191,000 miles, and I'm sure would continue to be solid with dino for it's life span. Any input would be appreciated.
Thanks,
Rick

 

[JZiggy]

Rick,

If you're at all worried about it then just stick with dino. Unless you're pushing your truck super hard it won't make a difference, especially if you are consistent on changes.

Synthetic will be more prone to leak than dino because it's so much thinner when cold. That being said, a good seal that is properly installed will not have a problem with synthetic. If synth makes it leak, then it was gonna leak before long anyway

 

[kolelt]

Differential fluid. Don't lose sleep over it. Stop over thinking it. Get valvoline 80-90 gear oil in a gallon. You can change the rear diff, transfer case and front diff. There's no science behind it. It's gear oil.

 

[jgue467]

I've not read of it here. I used wally world's 75-140 full synthetic on all 3 diffs about 125K ago, no leaks. :cowboy:

 

[pluton]

I use synthetic in all gear cases except the rear diff.
Why?
Because I'm a primitive....haunted by a thousand nameless demons, one of which is called
"Having the Rear Axle Seals Changed At My Local Dealer Service Department in 2013."

If they had a melted wax-looking, horror movie font I'd have used it.
If there is even a tiny, microscopic chance that the seals are more likely to leak with synthetic, I'll happily use good old 80W-90 and change it out more often. The rear diff oil is the hardest working gear oil on the truck, and it's a good idea to change it more frequently than the front diff,trans or transfer case anyway.

 

[montana4runner]

Thanks for the replies, guys. Pluton, that was my thinking and why I have asked this question. Lots of folks here have experienced leaking rear axles, just seeing if there were a chance it might be related to the change to synthetic. Probably not going to find enough data to make a claim one way or the other, but seems like an interesting study.

 

[bike]

If your looking for data on leaky axle seals after running synthetic, you might as well compare it to diff failures due to non-synthetic. My opinion - but it's not even worth the extra cost. Change it more often (I dont), or use that saved money for beer (I do)/gas/camping/other broken shit.