3 year maintenance Brake fluid/pad and rear differential fluid

[tracer bullet]

Robert (Thraxbert) has a list for all the bolts needed to dropping the subframe:

https://www.supramkv.com/threads/oem-suspension-bolt-kit.17261

Yessir, I've seen it. But I'm asking about the bolt for the damper, what you guys do with it when you swap rear diff fluids.

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[razorlab]

Yessir, I've seen it. But I'm asking about the bolt for the damper, what you guys do with it when you swap rear diff fluids.

I left mine off but I don't think you need to replace the bolt. It's not really structural.

 

[afree]

A lot of controversy around this one. Many say it’s okay and recommended it. But to be on the safer side, I asked back when I replaced mine because Turner MS sells the 105777, which works for both GL-4 & 5.

https://www.turnermotorsport.com/BMW-MZ4/c-1234-bmw-transmission-and-differential-fluid

Also was brought up on another tread ?

https://www.supramkv.com/threads/transmission-and-differential-fluid-change.6893/page-4

I also threw it into a multiple AI engine that checks others for discrepancies. Here’s what it spit out:

”Motul Gear 300 LS (105778) contains elevated friction modifiers (≥ 3.5% MOS2) that conflict with the electronic LSD’s preload calibration, potentially causing chatter during low-speed maneuvers.

Conclusion

The 2022 Toyota Supra 3.0’s differential unequivocally requires GL-5 75W-85/90 gear oil to meet its hypoid gear protection and electronic LSD compatibility needs. While aftermarket GL-4/GL-5 dual-rated fluids like Motul Gear 300 are acceptable, LS-specific formulations should be avoided. Adherence to Toyota’s 08885-02606 specification ensures optimal performance and preserves warranty coverage. For track-driven vehicles, reduce service intervals to 15,000–20,000 miles and monitor fluid condition using spectroscopy analysis.”

Just realized Toyota 08885-02606 is the OEM 'canned' GL-5 diff fluid. Thanks AI lol.

 

[FLtrackdays]

Just realized Toyota 08885-02606 is the OEM 'canned' GL-5 diff fluid. Thanks AI lol.

The OEM fluid would be perfect, of course, but it was hard to get quickly when I was shopping at the time. Then, as Bryan mentioned, I found out that Motul Gear 300 meets both GL-4 and GL-5 requirements, which I think is where AI ? lot of the confusion came from. The LS version added friction modifiers designed to reduce noise, vibration, and harshness (NVH). “However, since the limited-slip functionality in the Supra’s drivetrain is managed electronically rather than mechanically, it doesn’t require those friction modifiers. In fact, using the LS version could potentially cause concerns about compatibility with synchronized gearboxes.”

That sound about right?


Since our brake fluid is DOT 4 higher temp fluid, that should be changed at minimum every 3 years. I like Castrol’s SRF brake fluid. I know it’s a lot of money for brake fluid. But love knowing its boiling point is higher than most other DOT 4 fluid’s dry boiling points. I don’t do that on our other cars, since we shouldn’t be threshold braking in town on a repeated/regular basis, lol.

And back to brake pads, I drive on my track pads year round (being in a warmer climate). I used to switch them out after track days ? What a pain in the ass that was and waste of time! No problems leaving them on, other than the extra dust that comes with better stopping power. Same with our MX5. Never changed them after we stopped tracking that car. Black wheels also help ?

Lastly, since this is a 3 year maintenance thread, might as well mention spark plugs if anyone forgot to do that. It’s recommended to be changed 30k miles or 2 years I believe. And some peeps change them annually - if tracking.

 

[lucky phil]

What are you guys doing for the bolt that holds that damper which is in the way of getting to the plugs in the diff? Looks to be 28Nm / 21 ft lbs, but says to replace it (there's a dot by it in one image, and step a for getting it back together says to replace it). I find that odd. No way it's stretched or anything.

Elsewhere I'd mentioned that the rear subframe bolts didn't get replaced on BMW's but the Supra manual said they should be. Toyota seems to love to replace bolts?

These days the "replacement required" isn't necessarily because of TTY considerations but because the std bolt comes with a thread locker already applied from the factory. In other words the manufacturer doesn't trust the dealer techs to apply thread locker or the correct thread locker.

Phil

 

[Carbon0]

I personally doubt it’d be harmful with non track use. Especially once you let it warm up. In fact, like Christian said many recommend it (despite wrongfully so) not knowing ours isn’t a standard LSD. If you plan on tracking, stick to the OEM or Motul’s 105777. If switching, make sure all the 105778 is completely out of the system, they are not compatible. Many online videos explain how and experienced shops will know how to do it.


Yeah I spoke too quickly. Good point Bryan. If forgot shop I used advised against it after you explained it elsewhere. Lemme know if I got this right. Or at least partially right, lol. Using the LS (105778) could cause compatibility issues with our Electro-Mechanical LSD (eLSD).

The electro-mechanical LSD combines mechanical components with electronic torque vectoring. The electronic components and clutch packs need precise friction characteristics (minus modifiers), OEM or the Motul 105777 to operate correctly. The 105778 (Motul Gear 300 LS) contains friction modifiers for traditional (older style) mechanical LSDs, which is suggested they may interfere with the electronic torque vectoring system. All this could potentially lead to performance issues, premature wear, chatter, error codes, and lastly some mention cold weather stiffness or clunking until the fluid warms up.

Okay I ordered some OEM hypoid g4 fluid to put in instead of the 300 LS. Do I need to do anything special or should I just do it as usual?

 

[FLtrackdays]

Okay I ordered some OEM hypoid g4 fluid to put in instead of the 300 LS. Do I need to do anything special or should I just do it as usual?

Nothing special. The thread below list some of the caveats ?

https://www.supramkv.com/threads/transmission-and-differential-fluid-change.6893/page-4

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