Differential Overheating

[GregP27]

I’ve been reading with some interest about the differential overheating issues being experienced by the PP1 and PP2 cars. I got a new 2019 Mustang GT PP1, 6-speed manual, and started looking at the forum. Managed to hook up with a forum member, 1 old racer, and he related the following to me.

He has a 2018 GT PP1 and took it to the track several times. He overheated the first time (differential), so he resorted to an old hot rodder’s trick. He went home and wrapped the exhaust pipes where they cross the differential with header tape.

Next time at the track, no overheating. Seems like a simple solution for a problem caused by a hot exhaust pipe stupidly routed too close to the differential … or else any old Chevy big block with a hot header pipe near the starter. We did the same to make the starters last longer. Worked.

You might give 1 Old Racer’s solution a try and let us know your experience with it. Just FYI. I thought it might make several people think about simple solutions.

Cheers! ... and a cool rear end to you, too. :-)

- Greg

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[shogun32]

He went home and wrapped the exhaust pipes where they cross the differential with header tape.

This remedy has been posted multiple times in other on-topic threads, and is verified effective. And it's also dirt cheap.

 

[GregP27]

Thanks, Shogun. I hadn't seen it, but also wasn't watching for it, either.

Ah well, at least it seems to be a good solution for not much money.

 

[Prokiller]

its a bandaid but not a solution. it definitely will keep the temps down but will not cure the underlying problem of the diff being too small and not enough heat dissipation. other thing to do is swap out the fluid for a better one.

read through this thread:
https://www.mustang6g.com/forums/threads/2018-gt-pp2-rear-differential-overheating-issue.106844/

the only sure fire fix is to put in a cooler. there are two out there:
Ford GT350
https://lmr.com/item/M4000M8S/musta...Qk3EenSbVcxCdKCROMGJNqQ7vVevPPsEaApaPEALw_wcB
Full Tilt Boogie Racing
http://fulltiltboogieracing.com/S550_diff_cooler_kit.html

 

[cib24]

its a bandaid but not a solution. it definitely will keep the temps down but will not cure the underlying problem of the diff being too small and not enough heat dissipation. other thing to do is swap out the fluid for a better one.

read through this thread:
https://www.mustang6g.com/forums/threads/2018-gt-pp2-rear-differential-overheating-issue.106844/

the only sure fire fix is to put in a cooler. there are two out there:
Ford GT350
https://lmr.com/item/M4000M8S/musta...Qk3EenSbVcxCdKCROMGJNqQ7vVevPPsEaApaPEALw_wcB
Full Tilt Boogie Racing
http://fulltiltboogieracing.com/S550_diff_cooler_kit.html

Surely there is a universal cooler and cover that can be installed for far less than these two kits command?

 

[shogun32]

Surely there is a universal cooler and cover that can be installed for far less than these two kits command?

the back plate of the diff is highly unique. The only "easy" cooler is to run a length of condenser coil that dips into the oil and attaches to the outside thru 2 of the existing threaded holes with AN connectors. Where you put the coolant tank and mount the pump is left as an exercise for the reader.

If $100 worth of heat wrap basically solves the problem by blocking the radiant heat, why bother with anything that costs $1000 or even $500? It's not the hot air blowing over the diff that's the problem, it's the radiation.

 

[JohnVallo]

Reducing the differential temp can be achieved somewhat by doing these little things.
I painted my exhaust with Hi-Temp Silver Header paint. This keeps heat in the exhaust as well as controls rusting/corrosion.

If you're interested some advanced steps for controlling differential fluid temps (without the cooler)
SEE:
https://www.mustang6g.com/forums/th...-for-the-mustang-‘super-8-8’-rear-end.117720/

 

[ANGST]

I have my diff wrapped and run Reline 75w-140 , I can still overheat my diff in about 25-28 minutes of a 30 minute session .

 

[shogun32]

now here's a proper, engineered solution.

 

[3star2nr]

I did a track day got into limp mode and started obsessing over this issue a few years ago.

In the 3 years of ownership my rear diff has overheated a whopping 1 time... I think unless you regularly track your car or you are consistently hitting limp mode. Then you should do the swap.

I've driven pretty aggressively in the mountains of NC done multiple 16 hour road trips... Not one time did it overheat. So for a purely street vehicle you aren't going to encounter this issue unless you drive absolutely insane... And the diff at that point is the LAST thing you have to worry about.

That said... That boogie kit is a bargain! I May buy one just to have it, if i buy a second GT in the future

 

[Zinc03svt]

I would say unless it is a dedicated track car just wrapping the exhaust and change of better diff fluid would work for 95% of the road racers on here. I’m going to wrap my flowmaster axle back this winter.

 

[ANGST]

I would say unless it is a dedicated track car just wrapping the exhaust and change of better diff fluid would work for 95% of the road racers on here. I’m going to wrap my flowmaster axle back this winter.

I'd say I believed this until I got on the track ( wrapped exhaust and 75W-140 ) . I was running 30 minute sessions and got about 27-28 minutes in before the warning This was HPDE and not road racing. . So maybe I am in the 5% ?

 

[Grintch]

This remedy has been posted multiple times in other on-topic threads, and is verified effective. And it's also dirt cheap.

It's a bandaid. Like heavier fluid. It might work for you at a given track and a given driver agressiveness/performance, but if it was a complete solution Ford wouldn't bother to put diff coolers in the GT350 & GT500.

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