2018 GT PP2 Rear Differential Overheating Issue

[Norm Peterson]

i just emailed torsen and asked them about adding slick 50. im awaiting a response.

Much appreciated.


Norm

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[fatbillybob]

I'm pretty sure that the bias ratio would be affected. But I don't know by how much or even which way.

It may be possible to infer something if you can find information regarding the use vs non-use of normal limited slip additive in a Torsen. I suspect this would be easier to find than information regarding the use of Slick 50 in a Torsen directly.


Norm

If these are Torsen why can't the diff take more heat? Gears are not going to melt and the oils can take 300F temps pretty easy yet we get the axle over temp warning quite early. Oil viscosity protects the gears so just run a heavier weight that can take the heat too.

 

[shogun32]

the temp limits were likely established for the slip-diff clutch pack and never updated for the Torsen. Come on, you expected Ford to follow thru on coming up with numbers that correspond to the equipment? What's the breakdown characteristics (sheer film strength etc) of 75w120 gear oil at elevated temps?

 

[Norm Peterson]

If these are Torsen why can't the diff take more heat? Gears are not going to melt and the oils can take 300F temps pretty easy yet we get the axle over temp warning quite early. Oil viscosity protects the gears so just run a heavier weight that can take the heat too.

That's a valid option for a car owner, but maybe not for Ford unless they chose to eat a small mpg loss coming from a few cars against the fleet average and certify the car with the heavier oil.

Bias ratio has to be at least partly a consequence of friction somewhere in the mechanism. None of the video descriptions of a Torsen I've ever watched go that deep into it.


Norm

 

[thornclaw]

i just emailed torsen and asked them about adding slick 50. im awaiting a response.

havent heard back from torsen about this yet but i did find a link on torsen website about friction modifiers
digesting it it seems likely that slick 50 would decrease diff temp at the expense of impairing the diffs ability to limit slip
https://torsen.com/tbr-lube-friction-modifier/

 

[Champracerj]

I've also heard good things about Driven Racing products. (Joe Gibbs) designed to reduce temperature in Diffs, Trans, and engines.

Driven Racing Oil synthetic gear oil is specially formulated and designed to reduce operating temperatures by up to 15 degrees compared to other leading brands of gear oil. The gear oil also provides extra protection for ring gears, pinions, and bearings. Driven Racing Oil synthetic gear oil performs well in Ford 9 in. rear-ends, quick-change rear-ends, World of Outlaws Sprint Cars and late models, IHRA Pro Stock, Top Fuel Dragsters, and 24 Hours of Daytona vehicles.


I will be using this later this month and report my findings....

 

[shogun32]

Driven Racing Oil synthetic gear oil

this?
https://www.autozone.com/greases-an...p-street-or-track-gear-oil-1-quart/933197_0_0
I emailed them earlier this morning asking them to send me (and post on website) the technical datasheet. And what, if any Ford/GM specs it complies with or is fitment.

 

[thornclaw]

I've also heard good things about Driven Racing products. (Joe Gibbs) designed to reduce temperature in Diffs, Trans, and engines.

Driven Racing Oil synthetic gear oil is specially formulated and designed to reduce operating temperatures by up to 15 degrees compared to other leading brands of gear oil. The gear oil also provides extra protection for ring gears, pinions, and bearings. Driven Racing Oil synthetic gear oil performs well in Ford 9 in. rear-ends, quick-change rear-ends, World of Outlaws Sprint Cars and late models, IHRA Pro Stock, Top Fuel Dragsters, and 24 Hours of Daytona vehicles.


I will be using this later this month and report my findings....

thinking it through, there must be an optimal tbr for a given application. drag racing probably would do best with 100% or essentially a fixed axle. taking turns on a track would need less. the mustang being a mixed use car probably falls somewhere in between-a compromise. this could mean it would perform better on a track with a friction reducer in the diff. only one way to know. my ears are peeled as to the results of your test

 

[shogun32]

https://www.autozone.com/greases-an...p-street-or-track-gear-oil-1-quart/933197_0_0
I emailed them earlier this morning asking them to send me (and post on website) the technical datasheet. And what, if any Ford/GM specs it complies with or is fitment.

David@JoeGibs responded:

The 04230 is a GL-5 gear oil spec, and it has the proper friction modifiers for a limited slip differential. We do not rate a GM spec because we do not pay for the GM licensing

Driven Racing Oil 75W-90 GL5 synthetic gear oil is designed to provide the highest
level of protection in high speed and load environments. Driven 75W-90 is compatible
with hypoid and straight cut gears as well as open differentials, Torsen style differentials
and Detroit locker differentials. Driven recommends the use of Driven Gear Break-In oil
prior to using the 75W-90 gear oil if the gears have not been polished.

 

[Norm Peterson]

thinking it through, there must be an optimal tbr for a given application. drag racing probably would do best with 100% or essentially a fixed axle. taking turns on a track would need less. the mustang being a mixed use car probably falls somewhere in between-a compromise. this could mean it would perform better on a track with a friction reducer in the diff. only one way to know. my ears are peeled as to the results of your test

Have to think about this a bit. In a straight line there is no requirement for differentiation coming from the wheels and the difference in grip isn't likely to be anywhere near the bias ratio.

One thing I did hear somewhere was that a lower bias ratio might be better for running in the rain (daily driving up to wet track day), which may be why the S197 Boss got the 2.7 bias ratio unit when a 4.0 bias ratio was also possible.

I have a 2.7 Torsen for my '08 but haven't installed it yet.


Norm

 

[mustang5o]

David@JoeGibs responded:

Driven Racing Oil 75W-90 GL5 synthetic gear oil is designed to provide the highest
level of protection in high speed and load environments. Driven 75W-90 is compatible
with hypoid and straight cut gears as well as open differentials, Torsen style differentials
and Detroit locker differentials. Driven recommends the use of Driven Gear Break-In oil
prior to using the 75W-90 gear oil if the gears have not been polished.

For track days wouldn't it be better to look at the racing oil and possibly the 75W-140 racing oil? I sent them a message to see what they would recommend. Plus asked if they have a recommendation for the MT82.

 

[Champracerj]

For track days wouldn't it be better to look at the racing oil and possibly the 75W-140 racing oil? I sent them a message to see what they would recommend. Plus asked if they have a recommendation for the MT82.

The reason I posted about Driven Racing products is that their claims are that they reduce heat. The gear lube claiming 15 degrees. And I had someone with first hand experience using Driven Racing products in BMW track/race cars that indeed that was their result.

 

[wtb6mtv8rwd]

Just found this thread. I originally posted in the PP2 owner's thread in the general section but to summarize my issue:

Drive #1: Got axle temp warning: 293 degrees.

Drive #2: Upgraded diff fluid and added heat shielding to exhaust pipes. Same road, same conditions: no problem or warnings whatsoever, axle temps didn't go past 264 degrees.

Drive #3: Same roads, similar conditions (up to +5 degree ambient temps). Got axle temp warning at 270 degrees. Let it cool down. Drove again. Temp warning again at 270.

I'm a bit puzzled as to why I'm getting the warning at 270 degrees. By all accounts the threshold is 293. And it was when I first got the warning on drive #1.

A diff cooler is in my future but I'm curious if anyone has experienced this?

 

[Champracerj]

I'm a bit puzzled as to why I'm getting the warning at 270 degrees. By all accounts the threshold is 293. And it was when I first got the warning on drive #1.

From this thread " The word is that there are two limits: an initial warning of too hot gear oil, somewhere around 260F, and a final warning/limp mode, somewhere 280-300F. "

Which sounds about right I was getting the first warning at 265F. I never kept going to get the second and limp mode.

 

[wtb6mtv8rwd]

I've gone through the thread and seen the FTB kit mentioned a couple times without much follow up. Has anyone confirmed it actually works and solves all diff overheating issues?

Also has anyone swapped the diff cover by just loosening and supporting the diff instead of fully removing it from the car?

I'm not super enthused about having to pull the diff given that it would entail having to re-clock the bushings and re-align the car, all of which I literally just did.

This is becoming a little frustrating if I'm being honest. I bought a performance handling focused Mustang which I thought is built to carve canyons and I can't even do that.

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