2018 GT PP2 Rear Differential Overheating Issue

[ihasnostang]

does anyone have a stock diff cover that they could take pictures of so i could use a point cloud software to make a 3d model of it?

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[302@12psi]

Gale Banks engineering are working on diff covers that passively cool the diff fluid. They've been researching the problem for big trucks and find the high shearing action from the ring/pinion gear really heat up the oil with normal use. Under high loads the diff fluid overheats easily. They have some videos showing the churning and what their solution to the problem is. I heard on a podcast that they're going to make a cover for the S550 Mustang. If so, it should be a pretty simple fix that doesn't require wiring, plumbing or anything else. Probably a little early to get hopes up but the research is interesting. Point is the problem is internal to the diff, not primarly due to exhaust proximity although it probably is a factor.

Carcast?

 

[Gearz]

Carcast?

Could have been - it was there or The Smoking Tire.

 

[db252]

does anyone have a stock diff cover that they could take pictures of so i could use a point cloud software to make a 3d model of it?

 

[ihasnostang]

for photogrammetry to work the object needs several pictures with the object in a fixed postion (ie hanging from a wire). first minute after 0:52 explains it pretty well

https://youtu.be/NdpR6k-6SHs?t=52

 

[jameskhana]

The exhaust radiates an insane amount of heat, think it's literally the hottest thing outside of the engine. I didn't realize how much until I changed my exhaust and started getting crazy heat through the transmission tunnel doing hot laps. The exhaust runs even closer to that nice cast iron diff housing (why do we use cast iron for cooking?) what's needed is some proper heat shielding (not header wrap) to block that radiant heat. It's like if Ford was designing the exhaust to warm up the diff quickly, they did a great job, but unless you're in sub zero temps all the time it's a problem! Motorcycle style standoff heat shields would go miles toward improving the situation, and are not expensive. That plus a fluid change would be the easiest/cheapest/quickest first steps to take.

Couple different clamp-on heat shields can be found here: https://www.thermotec.com/products/heat-shields-and-protection

I ordered some heat shields for testing, just need to figure out how to access the factory temp sensor. I could rig some thermocouples on the outside but that's not oil temp or what the ECU is seeing.

@aleccolin Did you ever test the heat shields? Really liking this idea, especially that first flexible version for the exhaust curve around the diff.

 

[JohnVallo]

F Y I
(My intent for the following write-up was informational as well as to get these aftermarket companies to offer solutions for this problem)
https://www.mustang6g.com/forums/th...-for-the-mustang-‘super-8-8’-rear-end.117720/

 

[aleccolin]

@aleccolin Did you ever test the heat shields? Really liking this idea, especially that first flexible version for the exhaust curve around the diff.

No, I’ve been meaning to follow up but life got in the way and I haven’t even driven my car in while let alone worked on it. My intent is to get this done as soon as the weather breaks and I can get the Mustang on the lift. I’ll definitely report back with (hopefully) something substantive.

 

[NorthernBeast]

Can the rear diffuser and under body panels and ducts from the rear under body of the GT350 be fitted onto the rear of the 2018 GT? They both have quad exhaust and should have similar mounting points I'm thinking?

 

[sigintel]

F Y I
(My intent for the following write-up was informational as well as to get these aftermarket companies to offer solutions for this problem)
https://www.mustang6g.com/forums/th...-for-the-mustang-‘super-8-8’-rear-end.117720/

Thanks!
Awesome effort.
I did some testing with thermocouples hanging in the air in the trans tunnel and in front of diff.
Bottom line:
Its a hot air oven down there and you can basically expect +100F above ambient stock.

As you found with the finned cover, unless you route some cold air to hit the fins, Its tough to get teh diff cooler.
Its basically sitting in mostly +100F air from the headers, exhaust, trans case (bolted to the 230F engine) and driveshaft that are all acting as heatsinks for the engine and exhaust.
Might as well strap a brisket to the diff for your next road trip for that slow cooked flavor.

If you run some 2" or 3" air ducts to make an air curtain over the diff, I think you will be surprised how much that helps.
Insulating the exhaust including headers in front of and along trans tunnel would also help.

My next project is trying to come up with a simple, easy to copy air curtain system with cheap aluminum pieces.
Something we could open source would be best.
Goal is 50F drop or more for $50: would be huge for the track crowd.

 

[PoppinJ]

Thanks!
Awesome effort.
I did some testing with thermocouples hanging in the air in the trans tunnel and in front of diff.
Bottom line:
Its a hot air oven down there and you can basically expect +100F above ambient stock.

As you found with the finned cover, unless you route some cold air to hit the fins, Its tough to get teh diff cooler.
Its basically sitting in mostly +100F air from the headers, exhaust, trans case (bolted to the 230F engine) and driveshaft that are all acting as heatsinks for the engine and exhaust.
Might as well strap a brisket to the diff for your next road trip for that slow cooked flavor.

If you run some 2" or 3" air ducts to make an air curtain over the diff, I think you will be surprised how much that helps.
Insulating the exhaust including headers in front of and along trans tunnel would also help.

My next project is trying to come up with a simple, easy to copy air curtain system with cheap aluminum pieces.
Something we could open source would be best.
Goal is 50F drop or more for $50: would be huge for the track crowd.

You get that figured out and I'll be your first customer. I think some sort of scoop or something to divert a stream of air over the diff would be very helpful. I worry that in order to get cool air it would need to be the new lowest point on the car which could cause clearance issues. Also, your going to be putting a ton of air behind the rear bumper which could cause areodynamic issues. I'm interested to see what you come up with though.

 

[PoppinJ]

I've also wondered if the transmission cooler would cool the air in that area. It would go over a lot of hot stuff on the way to the diff but I'm there would be a lot of air cycling through there at higher speeds.

https://fordracingpartsbydonwood.co...PqrBCHMIDMsJEb4rGwmgOapmd9RLWLPQaAiOyEALw_wcB

 

[db252]

I'm happy to see that people are trying to find a cheaper resolution out there but it seems the only way to get a substantial temperature drop/control is to add a cooler whether it be the Ford branded one or the Full Tilt Boogie option which I have added and has made an incredible difference. When the pump kicks in I can literally watch the gauge go down and I've haven't been able to overheat the fluid yet on road course which wasn't the case before like so many of us seem to deal with. It is a a higher cost option but I'm continually intrigued by what most are trying to accomplish here.

For visual reference, this is my install: https://www.mustang6g.com/forums/threads/ftb-diff-cooler-installed.114217/

 

[sigintel]

You get that figured out and I'll be your first customer.

No purchase necessary, Id just pass all the sourcing info along. Day job makes me money so this would be all about Mustang grassroots track crowd. Its more about the challenge to find a simple solution.

I've also wondered if the transmission cooler would cool the air in that area. It would go over a lot of hot stuff on the way to the diff but I'm there would be a lot of air cycling through there at higher speeds.

I though about getting one just to see how much difference it makes all the back at the diff, but I suspect it just gets more hot air off the trans lol..

I'm happy to see that people are trying to find a cheaper resolution out there but it seems the only way to get a substantial temperature drop/control is to add a cooler whether it be the Ford branded one or the Full Tilt Boogie option which I have added and has made an incredible difference. When the pump kicks in I can literally watch the gauge go down and I've haven't been able to overheat the fluid yet on road course which wasn't the case before like so many of us seem to deal with. It is a a higher cost option but I'm continually intrigued by what most are trying to accomplish here.
For visual reference, this is my install: https://www.mustang6g.com/forums/threads/ftb-diff-cooler-installed.114217/

Saw your thread and thanks for posting it. Its great that works. I wish the cost and installation were lower. I ended up buying 3 used 3.15 diffs from a salvage yard and figured if I need to drop a diff from cooked seals or too much lash from injured pinion surfaces, I might as well just swap a functional used one in and move on. I know that sounds terrible, but I picked up 3 for $800 and they became disposable.

 

[shogun32]

I'll be using this wrap. Unfortunately there doesn't appear to be much in the way (any?) flat areas on the entire housing. I'm tempted to bolt on some copper CPU coolers with heat paste if I can find a suitable spot. Doubtful. What would be useful is to mill micro-grooves (say 3mm wide and 2mm deep - not sure how thick that casting is.) into the housing and dramatically increase the surface area of the casing.

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