Sponsored

"Rear Axle Differential Temp Increased, Decrease Speed" warning

EXP Jawa

Well-Known Member
Joined
Jun 9, 2014
Threads
3
Messages
1,011
Reaction score
206
Location
Rochester, NY
Website
www.torsen.com
First Name
Rick
Vehicle(s)
1999 Cobra Convertible, Electric Green
This smoothing out from static to dynamic would require more consistent movement or slipping than the stick/slip/stick/slip you are referring to, would it not? Is the more consistent slipping, which builds heat, the reason why the fluid is getting hotter in the road course environment?
I don't think it changes how often you've got movement, just the behavior when it does. Well, I suppose you could argue that the slight lowering of TBR means that there's the potential for slightly more slip. BUT, keep in mind that when driving, the gear rotation speeds are pretty low. A typical turn might be 20-30 RPM difference in axle speeds. That means that one gear rolls "forward" at 15 RPM, the other "backwards" at 15. You don't get much heating contribution in the axle system from the diff gearing. Yes, there is friction, but the dynamic friction only occurs occasionally and the relative speeds are low.

Also, on a road course, very little differentiation actually occurs. If you pulled wheel speeds from the vehicle's CAN bus, you'd see the rear wheel channels don't vary from each other much. Generally, when driven aggressively (high axle torques), the diff tends to stay locked, especially with TBR values. The ability (for a helical diff) to build friction and resist wheel spin is directly proportional to the amount of input torque, so high torque = high friction, which means little relative movement and little dynamic friction. The vast majority of heat generated in the axle system comes from the ring and pinion, as there is a substantial amount of friction in hypoid gearing, and that too goes up with torque load. You wouldn't see a significant differential contribution unless you forced continuous differentiation, like if you used a mini-spare tire at high speed. Obviously, that wouldn't happen at the track.
Sponsored

 

mnmike59

Well-Known Member
Joined
Apr 5, 2016
Threads
20
Messages
284
Reaction score
74
Location
2 hours South of BIR
Vehicle(s)
2016 Mustang GT PP
Changed the lube In the differential this afternoon. It looked good IMO, this was the third lube change I've done using Amzoil Severe Gear 75/90. Also this was after 5 hard 30 minute sessions at Brainerd International. (See the link in my Sig)
Link to what the lube looked like coming out>>>
 

GT_Roadcourse_Newb

noob@cartech,prefer2drive
Joined
Apr 8, 2016
Threads
32
Messages
834
Reaction score
152
Location
Rocklin, CA
First Name
John
Vehicle(s)
2016 GT-PP::2000 Honda s2000::1996 Nissan Maxima
Changed the lube In the differential this afternoon. It looked good IMO, this was the third lube change I've done using Amzoil Severe Gear 75/90. Also this was after 5 hard 30 minute sessions at Brainerd International. (See the link in my Sig)
Link to what the lube looked like coming out>>>
Ill try that (75/90, rather than 75/110) next, I think... Thanks for the video!
 

GT_Roadcourse_Newb

noob@cartech,prefer2drive
Joined
Apr 8, 2016
Threads
32
Messages
834
Reaction score
152
Location
Rocklin, CA
First Name
John
Vehicle(s)
2016 GT-PP::2000 Honda s2000::1996 Nissan Maxima
Is there any way to insulate the exhaust piping where they pass by the diff? No need to add any heat gain to the diff or even to the air in its immediate vicinity if diff heat is a known issue here.


Norm
Good job Norm
 

GT_Roadcourse_Newb

noob@cartech,prefer2drive
Joined
Apr 8, 2016
Threads
32
Messages
834
Reaction score
152
Location
Rocklin, CA
First Name
John
Vehicle(s)
2016 GT-PP::2000 Honda s2000::1996 Nissan Maxima
Makes sense to me. I guess I will start searching for the Aluminum Differential Casing Part number! :thumbsup: :hail:

(As an aside, I think I have found the part # for the GT350 aluminum crash bumper beam
FR3Z*17757*C
) :ninja:

[MENTION=8046]68fbjjz109[/MENTION] can you help me in my quest for an aluminum differential casing?
Ive had some challenges in being sure that I am getting the right part.

Interestingly, rep was mentioning a Roush casing in the attempt...
 

Sponsored

GT_Roadcourse_Newb

noob@cartech,prefer2drive
Joined
Apr 8, 2016
Threads
32
Messages
834
Reaction score
152
Location
Rocklin, CA
First Name
John
Vehicle(s)
2016 GT-PP::2000 Honda s2000::1996 Nissan Maxima
possible information repeat, but maybe worth it:

When replacing diff. oil, include a shot of friction modifier.


PRODUCT DESCRIPTION

Motorcraft Friction Modifier
Motorcraft XL-3 Friction Modifier is identical to Ford Racing M-19564-A Friction Modifier. It is specially formulated additive to provide smooth operation of clutch-type limited-slip differentials. One bottle of friction modifier is required when changing the gear oil in rear ends equipped with Ford traction-lok units.

https://lmr.com/item/M19546A/Ford-Racing-Friction-Modifier
 

Optimum Performance

Well-Known Member
Gold Sponsor
Joined
Mar 13, 2016
Threads
62
Messages
1,836
Reaction score
1,397
Location
Titusville, Florida
Website
www.facebook.com
First Name
Tommy
Vehicle(s)
'15 GT PP
possible information repeat, but maybe worth it:

When replacing diff. oil, include a shot of friction modifier.


PRODUCT DESCRIPTION

Motorcraft Friction Modifier
Motorcraft XL-3 Friction Modifier is identical to Ford Racing M-19564-A Friction Modifier. It is specially formulated additive to provide smooth operation of clutch-type limited-slip differentials. One bottle of friction modifier is required when changing the gear oil in rear ends equipped with Ford traction-lok units.

https://lmr.com/item/M19546A/Ford-Racing-Friction-Modifier
Not needed or recommended with aftermarket oils. That would be the "LS" in our Ultra Guard LS Axle Lubricant.
 
OP
OP
Brent Dalton

Brent Dalton

Sua Sponte
Joined
Mar 1, 2015
Threads
13
Messages
650
Reaction score
315
Location
GA
Vehicle(s)
2016 Mustang GT PP
So I am finishing up a 3 day event at Road Atlanta. It was a normal track day on Friday and NASA time trials on Saturday and Sunday. Temp was low 90's and super humid. Time trial session are 15-20 minutes, but the track day sessions were w0-25. After the session was over I would drive up and down the road to help cool everything back down. No warnings this weekend. I'll drain the fluid sometime this week and report back how it looks. It is amsoil 75w110 I think. I posted what I put in before. It was just what I had sitting on the shelf as it is what I run in the rx7 as well. Hallett next weekend.
 

Sponsored
OP
OP
Brent Dalton

Brent Dalton

Sua Sponte
Joined
Mar 1, 2015
Threads
13
Messages
650
Reaction score
315
Location
GA
Vehicle(s)
2016 Mustang GT PP
Yes! Another good point i failed to mention.. Advancetrac off.

I was only able to manage 1:39's. I was hoping for a 37. Beat all the other mustangs it looks like though. I was rather surprised to roll across the scales at 3902 lbs with an empty tank today (base GT with PP as the only option). I'm about 200 lbs with full gear on. It made a little more sense as I was getting pulled by a TTB car or two (which i knew i wasnt maxed for powe either). I think the car has a 35 in it with some fresher tires and some cooler weather. Overall a fun weekend.
 

GTF1

Member
Joined
May 5, 2016
Threads
0
Messages
22
Reaction score
8
Location
Lawrenceville, GA
Vehicle(s)
2016 Mustang GT PP Race Red
1:39 is very respectable time, what mods and tires do you have in your car?
Thanks for sharing
 
OP
OP
Brent Dalton

Brent Dalton

Sua Sponte
Joined
Mar 1, 2015
Threads
13
Messages
650
Reaction score
315
Location
GA
Vehicle(s)
2016 Mustang GT PP
aFe coilovers and sway bars. All stock bushings. All stock engine at 370rwhp. Kognition wing and apr splitter. Hoosier R7 tires that have about 8 days on them now. They still have good grip, but not as good as when they were fresh.
 
OP
OP
Brent Dalton

Brent Dalton

Sua Sponte
Joined
Mar 1, 2015
Threads
13
Messages
650
Reaction score
315
Location
GA
Vehicle(s)
2016 Mustang GT PP
I'll post videos in the next few days in my build thead aND the lapt8me thread.. I would have already, but my laptop stopped working this weekend. :/
Sponsored

 
 








Top