Gen 2 Rear Diff Durability - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

KillerBMotorsport · 03-24-2023, 06:41 AM

Not having any issues except for really enjoying wagging the tail in this thing.

It has me wondering if anyone has experienced and rear diff durability issues?

If you did have a problem or failure, were there any initial symptoms or indications that it was starting to go, or did it just outright fail?

Any thoughts of feedback appreciated!

.

alex87f · 03-24-2023, 08:00 AM

Isn’t it the same part as the first gens? And weren’t the first gen diffs known to be able to handle a lot more power / torque than the stock specs ?

KillerBMotorsport · 03-24-2023, 09:08 AM

Quote:

Originally Posted by alex87f

Isn’t it the same part as the first gens? And weren’t the first gen diffs known to be able to handle a lot more power / torque than the stock specs ?

That I don't know, we never owned a Gen 1 car.

Being able to handle a lot of power is good, but cornering, or sliding through corners is what I would think would torch a diff.

I see some of the track guys have upgraded the diff. For improved durability, or for improved locking?

Hopefully I'm concerned over nothing

dragoontwo · 03-24-2023, 09:16 AM

Quote:

Originally Posted by alex87f

Isn’t it the same part as the first gens? And weren’t the first gen diffs known to be able to handle a lot more power / torque than the stock specs ?

Yes.

Quote:

Originally Posted by KillerBMotorsport

That I don't know, we never owned a Gen 1 car.

Being able to handle a lot of power is good, but cornering, or sliding through corners is what I would think would torch a diff.

I see some of the track guys have upgraded the diff. For improved durability, or for improved locking?

Hopefully I'm concerned over nothing

It's to change to a true LSD with a clutch type lock up.

nextcar · 03-24-2023, 10:21 AM

Furthermore it is the same diff that is used in some Lexus vehicles, FWIW...

When I changed the final drive gearing in mine, I spoke at length with a shop that specialized in setting up diffs and they commented how they don't see many of these because "they rarely fail".

KillerBMotorsport · 03-24-2023, 12:56 PM

Quote:

Originally Posted by dragoontwo

It's to change to a true LSD with a clutch type lock up.

What is the benefit of that?

KillerBMotorsport · 03-24-2023, 12:57 PM

Quote:

Originally Posted by nextcar

When I changed the final drive gearing in mine, I spoke at length with a shop that specialized in setting up diffs and they commented how they don't see many of these because "they rarely fail".

That's good to hear.

DocWalt · 03-24-2023, 02:03 PM

The second gen diffs seem to overheat more quickly than first gen diffs, no surprise with the extra power.

Quote:

Originally Posted by KillerBMotorsport

What is the benefit of that?

More tunable than the stock Torsen, you don't have to worry about tuning suspension setup around inside rear wheel lift.

Lelandjt · 03-24-2023, 02:29 PM

Quote:

Originally Posted by nextcar

Furthermore it is the same diff that is used in some Lexus vehicles, FWIW...

When I changed the final drive gearing in mine, I spoke at length with a shop that specialized in setting up diffs and they commented how they don't see many of these because "they rarely fail".

I'm interested in putting taller gearing in my diff (I assume you went the other way) so any info you can give me to track down parts would be useful.

zeroomega · 03-24-2023, 03:01 PM

Gen1 diff rarely fail, even among track folks. It is a torsen unit, which is robust and mostly worry free. People who upgrade the diff are mostly for changing into clutch type LSD for tunability and better locking behaviors (this type of differentials are actually need more attention and are less robust than the torsen) . IIRC the torsen on gen1 (and probably gen2) has a fixed 1:4 bias ratio and it cannot be changed. If one rear wheel lost contact with the ground (which is common with larger swaybar or higher spring rate coilovers), the torsen LSD effectively becomes an open diff.

vindiesel · 03-24-2023, 04:29 PM

Clutch kicks/dumps per mileage ratio durability. Who’s tracking?

whataboutbob · 03-24-2023, 04:45 PM

Quote:

Originally Posted by KillerBMotorsport

What is the benefit of that?

Among many other things, the ability to effectively get on throttle earlier on corner exit.

OkieSnuffBox · 03-24-2023, 05:26 PM

Diffs in general tend to be pretty robust, even with high HP as long as you aren't doing clutch dumps or what can happen on track sometimes where on corner exit you're on throttle and drop a rear wheel off the tarmac. It's the shock loads that tend to really hurt stuff.

Pat · 03-24-2023, 08:31 PM

The differential on my 2014 BRZ wore out after about 130,000 mi. It wasn't exactly kaput, but I could feel a difference with the car up in the air between the original diff and one in very good condition. It also had about 130 track days on it with fluid changes maybe every 20,000 miles.

03-24-2023, 06:41 AM	#1
KillerBMotorsport Join Date: Apr 2021 Drives: BRZ Location: Virginia Posts: 568 Thanks: 89 Thanked 710 Times in 324 Posts Mentioned: 15 Post(s) Tagged: 0 Thread(s)	Gen 2 Rear Diff Durability Not having any issues except for really enjoying wagging the tail in this thing. It has me wondering if anyone has experienced and rear diff durability issues? If you did have a problem or failure, were there any initial symptoms or indications that it was starting to go, or did it just outright fail? Any thoughts of feedback appreciated! .

03-24-2023, 04:29 PM	#11
vindiesel Senior Member Join Date: Nov 2022 Drives: 2023 brz limited 6mt red Location: Greenville sc Posts: 177 Thanks: 151 Thanked 141 Times in 73 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Clutch kicks/dumps per mileage ratio durability. Who’s tracking? __________________ 2023 brz red limited 6mt 10k miles ish 2009 Chrysler 5.7l hemi eagle 300c heritage edition 205k miles

03-24-2023, 05:26 PM	#13
OkieSnuffBox Senior Member Join Date: Aug 2014 Drives: '23 BRZ Limited Location: OKC, OK Posts: 1,987 Thanks: 660 Thanked 1,230 Times in 703 Posts Mentioned: 9 Post(s) Tagged: 1 Thread(s)	Diffs in general tend to be pretty robust, even with high HP as long as you aren't doing clutch dumps or what can happen on track sometimes where on corner exit you're on throttle and drop a rear wheel off the tarmac. It's the shock loads that tend to really hurt stuff. __________________ "95% of the time, more throttle is the answer. 5% of the time, it ends the suspense."

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03-24-2023, 08:00 AM	#2
alex87f Meow Join Date: Aug 2017 Drives: GT86, Volvo 996 Location: France Posts: 535 Thanks: 317 Thanked 445 Times in 237 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Isn’t it the same part as the first gens? And weren’t the first gen diffs known to be able to handle a lot more power / torque than the stock specs ?

03-24-2023, 03:01 PM	#10
zeroomega Member Join Date: Jul 2018 Drives: Supra MKV, FR-S Location: Bay area, CA Posts: 72 Thanks: 22 Thanked 67 Times in 27 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Gen1 diff rarely fail, even among track folks. It is a torsen unit, which is robust and mostly worry free. People who upgrade the diff are mostly for changing into clutch type LSD for tunability and better locking behaviors (this type of differentials are actually need more attention and are less robust than the torsen) . IIRC the torsen on gen1 (and probably gen2) has a fixed 1:4 bias ratio and it cannot be changed. If one rear wheel lost contact with the ground (which is common with larger swaybar or higher spring rate coilovers), the torsen LSD effectively becomes an open diff.

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