"Rear Axle Differential Temp Increased, Decrease Speed" warning

[pstoppani]

Yes, I saw the AdvanceTrac Off msg but still got some assistance when it got only a few degrees sideways.

I don't see how and assist has any effect on a Torsen diff since the assist uses brakes and throttle... and I only saw the assist light flicker a handful of times all day.

BTW - The Android ForScan app and the obdLink MX worked great for keeping an eye on the temp. The diff was at around 235F at the start of each session, hit the magic 284F warning within 10 minutes and kept going up to 315F at 20 minutes consistently. Wonder what hits at 30 minutes!

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[pstoppani]

Maybe change your diff oil after a couple thousand miles (after the diff is well broken in) and see if it changes?

I'm changing it next week to see what it looks like after being well cooked! Should be broken in at this point.

 

[GTF1]

Steve,
I'd say you are right. I thought GTF1 reported it going into limp mode on the secondary warning, ending his day at Road Atlanta. Sounds like I am rembemering incorrectly.

Sorry for the delayed response, no Limp Mode, just the warnings.

 

[Norm Peterson]

Yes, I saw the AdvanceTrac Off msg but still got some assistance when it got only a few degrees sideways.

I don't see how and assist has any effect on a Torsen diff since the assist uses brakes and throttle... and I only saw the assist light flicker a handful of times all day.

WAG - perhaps having braking on only one of the rear wheels makes the gear train inside the diff work harder or puts the gears under heavier tooth loading :shrug:


Norm

 

[pstoppani]

WAG - perhaps having braking on only one of the rear wheels makes the gear train inside the diff work harder or puts the gears under heavier tooth loading :shrug:
Norm

I had the assist kick in max twice in a single session and the diff temp hit 318F after 20 minutes. The assist surely had almost zero effect on the temp in my case.

Regardless, for lots of hard track days, the diff needs a cooler.

The Mustang is my DD and not my primary track car (which is a BRZ) so I can live with it for the handful of days I plan to track it.

 

[Optimum Performance]

I drove mine for the first time (900 miles on the odometer at The Ridge Motorsport Park in Shelton WA. Hit the warning every session except first, with diff temp hitting 318F at the end of each 20 minute session! This in 64F ambient! Ouch, that is HOT!

Car is stock except for camber plates, G-Loc 12/10 pads and RE71 265s on 19" wheels.

Drove pretty hard (1:57's). I tried with traction control "off" and AdvanceTrac off. No difference. I did notice that in both modes there was still driver assist when the car goes a bit sideways; I was under the impression all driver aids were off when AdvanceTrac is off?!?

Fixed it for you

I have had it "come back on" during an aggresive session chasing a well driven M Series and I know it was off at Pit Out. I wrote it off as fat thumbs but several people have felt intervention with everything "off" It started showing up more every lap through a quick switchback section. It actually scared me because it felt like the car was stopping in mid drift and I needed to adjust my wheel input. I finally pitted and shut it off and it never came back on.

 

[Impulsed7]

Supposedly its brake controlled torque bias, but I bet there's still quite a bit of traction control going on back there.

 

[pstoppani]

I have had it "come back on" during an aggresive session chasing a well driven M Series and I know it was off at Pit Out.

Hmm, maybe it comes on automatically when chasing down a M car since that is when it kicked in for me too :cheers:

 

[MaverickGT]

Upgraded to 75w-140 a month back. Last weekend last two session were the fastest and no warning light. Today at TWS with Chin 30 min sessions. Had the warning light come on three times right about the 28 minute mark before the cool down lap. This is much better than the warning light coming on prior in 20 min sessions (though it was July in Texas).

 

[MaverickGT]

Update day2. Had the warning each session. Session 3 was 18 minutes into it. The temp was 97 in the afternoon. Definitely need some cooling.

 

[Impulsed7]

Anyone put a spacer or some foam on the sensor? I havent seen a failure yet...

 

[EXP Jawa]

A spacer or foam won't change the fact that your axle lube is approaching the temp at which the oil begins to break down. You haven't seen a failure yet because the potential failure is long term degradation of bearings, gearing, etc due to the compromised lube.

Folks that are changing out their axle oil right away or frequently due to track use will side step the issue. But without doing that, you're operating in cooked oil. The point of the sensor, I believe, is to prevent that from happening. Simply being blind to the condition doesn't mean it won't happen...

 

[mnmike59]

Update day2. Had the warning each session. Session 3 was 18 minutes into it. The temp was 97 in the afternoon. Definitely need some cooling.

Do you change the fluid after each "track day"?

 

[Impulsed7]

A spacer or foam won't change the fact that your axle lube is approaching the temp at which the oil begins to break down. You haven't seen a failure yet because the potential failure is long term degradation of bearings, gearing, etc due to the compromised lube.

Folks that are changing out their axle oil right away or frequently due to track use will side step the issue. But without doing that, you're operating in cooked oil. The point of the sensor, I believe, is to prevent that from happening. Simply being blind to the condition doesn't mean it won't happen...

I'm not talking about ignoring it. I am talking about preventing the limp mode. I for one change the fluid every other track day or so, sometimes after every one.

 

[ANGST]

I'm not talking about ignoring it. I am talking about preventing the limp mode. I for one change the fluid every other track day or so, sometimes after every one.

Didn't we already go through that there was no limp mode , just the warning?

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