"Rear Axle Differential Temp Increased, Decrease Speed" warning

[MaverickGT]

There's some nice work being done but for us who may not have the experience doing this is there any word on when we might expect a turnkey solution?

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[GT_Roadcourse_Newb]

Progress

Niiice eye candy!

 

[Optimum Performance]

There's some nice work being done but for us who may not have the experience doing this is there any word on when we might expect a turnkey solution?

Working very hard on it.

 

[Brent Dalton]

So some more information. [MENTION=22413]Optimum Performance[/MENTION] showed me last week that:

1. The rear diff temp sensor port on the diff cover does not go through the metal cover and into the diff fluid and
2. The rear diff temp sensor has the same part number as the air intake temp sensor.

There are several reasons I can think of for doing the two things listed above(one less point of failure/leak point, possibly cheaper sensor, don't have to drain fluid to change sensor, possibly less heat soak/fluctuation, etc..), but ultimately only Ford knows. Not anything I'm concerned about being accurate or anything, just wanted to share as I found it interesting.

Some pictures showing this on a GT350 cover:




Sensor port from fluid side:

 

[mnmike59]

So some more information. [MENTION=22413]Optimum Performance[/MENTION] showed me last week that:

1. The rear diff temp sensor port on the diff cover does not go through the metal cover and into the diff fluid and
2. The rear diff temp sensor has the same part number as the air intake temp sensor.

There are several reasons I can think of for doing the two things listed above(one less point of failure/leak point, possibly cheaper sensor, don't have to drain fluid to change sensor, possibly less heat soak/fluctuation, etc..), but ultimately only Ford knows. Not anything I'm concerned about being accurate or anything, just wanted to share as I found it interesting.





Some pictures showing this on a GT350 cover:




Sensor port from fluid side:

Great info!
Now I'm really interested in finding out why running a little heavier gear lube lessens the warnings??
Great thread! It would be nice to have someone within Fords engineering/design department chime in. You know someone must see these threads?:shrug: Right?

 

[Optimum Performance]

You need a less robust sensor, you already make one, no leaks, easy to swap.

Our dealer in Germany failed his pinion bearing 10 hours in during the 24 hour race due to a oil flow issue through the cooler. 3.73's spin that bearing much faster than a numerically lower ratio. Hence Ford started monitoring it. Hence the interest in cooling.

Heavier oil just doesn't shear as fast at 300F. I bet during a 50 minute track session you could get the light to come on without cooling. The 75W-140 (and 110) seems to make it through a typical 20 min session. The 90 even made it more laps than the stock 85 LOL

 

[16s550]

Don't think I'll see more than 20 min sessions so I should be good with the thicker oil? Don't plan on adding cooler till way later

 

[Bahndvr]

The tag on my 03 Mustang Cobra diff cover said, 75w-140. From the factory it was 3.55

 

[EXP Jawa]

I think the biggest reason for not having a sensor in the lube itself is what I described earlier - the lube doesn't sit in a stagnant pool where it can be measured. This is splash lubrication - it isn't like plugging a thermocouple into a waterjacket, where there is guaranteed flow past it. The oil is being flung everywhere by the ring gear, and there isn't enough volume in there to have a continuous flow past a sensor. Even if it was in the bottom - where it'd be more damage prone - it wouldn't have a constant amount of lube over it to get a constant reading on.

The best you can really do is measure the heat level that's been transferred out to the case. So, you aren't measuring lube temp, but rather system temp at an outer location. Sort of like measuring cylinder head temp compared to oil temp.

If the oil volume was greater, like in the S197 axle where there'd be oil out into the axle tubes when sitting still, you'd have a much better chance of getting some constant level of oil pooling in a sump that you could put a probe into. If some devises a new cover that has more volume capacity, you could go in that direction. But in this case, it'd be real difficult to get a lube temp reading in the stock set up.

Another note - Ford moved to the 75W-85 across the board for fuel economy reasons. It is not because its a better lube, or more durable in extreme conditions. So, even though the axle is set up around that lube, something else will probably be a better choice for track use.

 

[Brent Dalton]

Thanks for the insight! I was hoping you would post.

 

[steveespo]

What is the thread pith on the sensor tapping? It was metric on the 13-14 GT 500 cover and I retapped for 1/8 NPT to fit AutoMeter sensor. I bore holed the blind side and have gotten steady readings at high and low speeds and when my pump is on or off in my 2011 Track car.
Steve

 

[Norm Peterson]

If the oil volume was greater, like in the S197 axle where there'd be oil out into the axle tubes when sitting still, you'd have a much better chance of getting some constant level of oil pooling in a sump that you could put a probe into. If some devises a new cover that has more volume capacity, you could go in that direction. But in this case, it'd be real difficult to get a lube temp reading in the stock set up.

I'm curious about how much lube the S550's IRS takes.

The IRS also loses all the extra surface area of the axle tubes as paths of heat rejection, and the oil can't be sitting at any steady level in them either.


Norm

 

[Optimum Performance]

I'm curious about how much lube the S550's IRS takes.

The IRS also loses all the extra surface area of the axle tubes as paths of heat rejection, and the oil can't be sitting at any steady level in them either.


Norm

1.7 L roughly.

 

[Norm Peterson]

Thanks, Tommy.

Seems odd that Ford designed the casting to be about half a pint shy of two full bottles of lube . . . <scratches head>


Norm

 

[Gatorac]

CoolTech has just produced a Focus RS RDU cooler in the style of the Boss 302 transmission cooler. A scoop that hangs down and directs more air flow over the unit. Perhaps this may be a solution that provides enough cooling for typical track day use on the GT. I'll admit that I haven't looked under the car from the perspective of adding a scoop.

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