Just got my differential temperature guage all hooked up. Now, does anybody know what too hot is?

 

Dug this up for you, the reference between break in and already broke in lube may be irrelevant, but I though it would give you a good idea on temps.

Further evidence of stress and increased temperatures during the differential break-in period is documented in a 2005 SAE paper titled “The Effect of Heavy Loads on Light Duty Vehicle Axle Operating Temperature.” A light duty GM truck towing 14,000 pounds was driven from Orange County, Calif. to the Nevada state line. The test was conducted with both a new axle and a broken-in axle. Over level ground towing, oil temperature was measured at 230 degrees F in the new axle and 203 degrees F in the broken-in axle. Oil temperature over the most grueling portion of the trip, during which a maximum 6 percent grade was encountered, revealed the new axle was operating at 350 degrees F and the broken-in axle was operating at 300 degrees F. Laboratory dynamometer test results simulating a truck hauling a trailer provided similar results, with level ground towing temperatures recorded at 266 degrees F with the new axle and 194 degrees F with the broken-in axle and towing temperatures (at a 3.5 percent grade) recorded at 370 degrees F with the new axle and 295 degrees F with the broken-in axle.

 

HOLY SMOKES!! That's WAY hotter than I expected they'd get! I guess that '08 finned diff cover is a good mod then...

I checked mine the other day after about an hour drive (empty), and it was warm, but not hot to the touch. I could leave my hand on it indefinitely. This was before I put the '08 cover on, BTW. I guess I'll add a diff cover to the list of mods for building the ultimate 7.3 towing machine...

 

Yeah, that IS hot.
About 100 degrees hotter than I would have guessed.

 

yeah that is !!

I have a Mag Hytec pan, and synth fluid and mine (even towing) never goes over 150 ..

 

Everybody has syn fluid -- 75W-140 only comes in syn AFAIK. I put the '08 cover on mine this weekend, but only because I couldn't stand the look of the rusty POS stocker. Where does the temp sender go? In the fill port?

BTW, I pulled the sensor off to see if there was any scuzz on it, and there was some. Far more on the magnetic fill plug, though. Which brings up a good point -- if you use the fill port for the temp sender, do you put a magnet somewhere else?

 

i knew that

 

 

Most pickup trucks, SUVs and vans operate in severe service conditions, including towing, hauling, steep hill driving, commercial use, plowing, racing, off road use, rapid acceleration, frequent stop and- go operation and high ambient temperatures. These severe service operating conditions subject the differential to extreme pressures and operating temperatures.
New vehicles such as turbo diesel trucks and vehicles with V-10 engines boast more horsepower and torque than their predecessors, but differential designs have remained virtually unchanged. Differentials today are subjected to severe duty service and encounter more stress and heat than was seen only a few years ago. Modern gear oils are faced with the challenge of providing adequate wear protection during severe service operating conditions, while also providing maximum fuel efficiency.
In fact, according to a 2005 SAE paper entitled Breaking the Viscosity Paradigm: Formulating Approaches for Optimizing Efficiency and Vehicle Life, "Concurrent with the strong drive toward better fuel economy, consumers have been demanding increased performance, which has required axle lubricants with enhanced durability protection and lower operating temperatures. There has been a 34% increase in engine horsepower over the last decade, while axle gear sizes have remained constant, sump capacities have been lowered, and drain intervals extended. In the light truck segment there has been a 93% horsepower increase since 1981."
Further evidence of stress and increased temperatures during the differential break-in period is documented in a 2005 SAE paper entitled The Effect of Heavy Loads on Light Duty Vehicle Axle Operating Temperature. A light duty GM truck towing 14,000 pounds was driven from Orange County, Calif. to the Nevada state line. The test was conducted with both a new axle and a broken-in axle.
Over level ground towing, oil temperature was measured at 230 degrees F in the new axle and 203 degrees F in the broken-in axle. Oil temperature over the most grueling portion of the trip, during which a maximum 6% grade was encountered, revealed the new axle was operating at 350 degrees F and the broken-in axle was operating at 300 degrees F. Laboratory dynamometer test results simulating a truck hauling a trailer provided similar results, with level ground towing temperatures recorded at 266 degrees F with the new axle and 194 degrees F with the broken-in axle and towing temperatures (at a 3.5% grade) recorded at 370 degrees F with the new axle and 295 degrees F with the broken-in axle.

i got the info here
Severe Gear differential oils

 

Looks like the same quote Ziggy posted, Ron... LOL

 

ill go back too my corner...and lay down by my dish

 

Lmao!!!!!

 

Yes you should have a magnet in the diff somewhere, any little metal shavings dont get along with seals
Its all good man

 

I've observed in the 130 range with normal driving, don't know about towing.

 

Thanks all, I could be wrong but I don't think our trucks are "light duty". Don't know what kind of chebby they measured but I'm suspecting a half ton. That sounds like an add for some kind of lube additive or something. so far I haven't been able to get the guage to hardly move. The tranny got warmer than the diff. LOL, the guage only goes to 250 and I suspected that I would back off at 220 or so, kinda like the tranny. I got the mag-hytec which has a port for the sender. I was kinda suprised the port was on the top but I guess they know what they are doing. If it runs as hot as that post says mine would have burned up a long time ago. But it looked great last week when I changed out the cover.