Drive differential temps

dieselengineer

Charter Member
Does anyone monitor your differential temperatures while towing? Or after towing, at a stop, use the thermo infrared gun to read the temperature of the rear cover? If so, what is the average temp?
 

Bob&Patty

Founders of SoCal Chapter
Jim, no I dont but thats a great idea. I need to install some guages on the "A" pillar, EGT and trans temp. Someone might make a diff temp guage that would fit in one of those. And maybe a sender that might fit into the drain plug on the diff. What a concept. Bob:D
 

MC9

Well-known member
I recently changed from a 3.73 to a 4.10 rear end. The mechanic (that is all they do) said 200 was OK but don't get to 300. I never got over 150. If this helps. I do love my temp gun.
 

Ray LeTourneau

Senior Member - Past Moderator
Jim, no I dont but thats a great idea. I need to install some guages on the "A" pillar, EGT and trans temp. Someone might make a diff temp guage that would fit in one of those. And maybe a sender that might fit into the drain plug on the diff. What a concept. Bob:D
I wonder if a water temp sensor would fit or be adaptable to the drain plug hole? I've never given thought to checking the temp on the differential.:eek: Probably a good idea though.
 

nhunter

Well-known member
I had a 76 Kenworth that had front and rear diff temps. Never ever checked the Ford though.
 

porthole

Retired
I have a Mag Hytec diff cover on my GMC. Holds almost 8 quarts (stock holds about 2).

I have the temp sensor and gauge. Going out to Indiana from New Jersey (non stop) my diff temp was just below 150.

Coming home (also non stop) with the Cyclone the temp was the same.

BTW, the sensor mounts at the top of the cover, so I am guessing it is the housing temp and not necessarily fluid temp, but it would be "splashed" by the ring gear, just not immersed.
 

Rigmover06

Well-known member
Diff Temp Sending unit.

Does anyone monitor your differential temperatures while towing? Or after towing, at a stop, use the thermo infrared gun to read the temperature of the rear cover? If so, what is the average temp?

I did install a temp gauge on our 3500 for the rear diff and under maximum load the hottest I got was 180. I have synthetic gear oil in mine.

It was a simple install. I will try to find the pictures I took while I was doing it and post them on here if allowed to.

Dan
 

dieselengineer

Charter Member
For heavy towing, the change interval for the rear diff (Dodge) is 15,000 miles. Appears that this is due to the temps and duty that the lube is subjected to during heavy towing. The mag hytec covers are very well made, and in the long run can be cost effective if the drain intervals can be extended due to not cooking the lube. However, when the black coal is pouring out the pipe and the boost is at it's maximum, the temps keep on climbing. I know, there should not be black coal pouring out the pipe, but what fun would that be.
 

nhunter

Well-known member
For heavy towing, the change interval for the rear diff (Dodge) is 15,000 miles. Appears that this is due to the temps and duty that the lube is subjected to during heavy towing. The mag hytec covers are very well made, and in the long run can be cost effective if the drain intervals can be extended due to not cooking the lube. However, when the black coal is pouring out the pipe and the boost is at it's maximum, the temps keep on climbing. I know, there should not be black coal pouring out the pipe, but what fun would that be.

Maybe that should be 150,000 miles! Ford calls for 97,500m intervals on the F-450, F-550 and 150,000m on the F-350. Somethings wrong if it is only 15,000m.
 

porthole

Retired
I am sure with only 2 quarts in the diff my temp would have been higher.

I really like the big covers, almost four times the fluid and I used Amsoil when I did it.

I think I will probably never have to change the oil. Maybe I'll have the truck for another 100,000 or not.

But if I do change it the Mag Hytec cover come with a drain plug, a center plug for quick filling to about 80-90 % capacity and then a top fill port with a dipstick for final filling.
 

dieselengineer

Charter Member
nhunter
Differentials today are subjected to "severe" duty service and encounter more stress and heat than was seen only a few years ago, simply due to the fact that today's engines have more HP and Torque. Extreme pressures and temperatures generated within the differentials increase stress on the lubricant. Schedule "B" in the dodge owner's manual calls for lube changes every 15,000 miles. It is not the same as "back in the day"
 

Bob&Patty

Founders of SoCal Chapter
Duane, you sure your GMC only had 2 qts? When I changed mine to synthic it took almost 4 qts. I have the same diff as you. Bob:D
 

porthole

Retired
Bob - just guessing on the fluid, might have been a little more then 2 - but I doubt it was more then 3 or a little over that.
 

nhunter

Well-known member
nhunter
Differentials today are subjected to "severe" duty service and encounter more stress and heat than was seen only a few years ago, simply due to the fact that today's engines have more HP and Torque. Extreme pressures and temperatures generated within the differentials increase stress on the lubricant. Schedule "B" in the dodge owner's manual calls for lube changes every 15,000 miles. It is not the same as "back in the day"
The numbers for the Ford I quoted aren't "back in the day" they are from 2006. With that thought Kenworth owners must be changing theirs every 10 miles!
 

dieselengineer

Charter Member
nhunter
I disagree with your comparison with a "kenworth". The ring and pinion gears are not in the same league and they have larger surface area to handle the torque with less heat and stress on the lube.
 

nhunter

Well-known member
nhunter
I disagree with your comparison with a "kenworth". The ring and pinion gears are not in the same league and they have larger surface area to handle the torque with less heat and stress on the lube.

I know they are not in the same league, just seems odd Dodge says 15000m and Ford says 150000m. Thats all. ;)
 

dieselengineer

Charter Member
The first thing I noticed was the paint on the cover coming off due to the heat being generated during towing. After the first drain (change of lube) and seeing the black tar that came out after only 10,000 miles, I understand why dodge has the service interval at 15,000 miles for the servere duty. The lube appears to be cooked and burnt. The second change with synthetic was a little better. So that is why I was asking about temps everyone was seeing. Presently have a mag-hytec cover, extra lube, and the temp probe. The lube appears to be nice and clear, however I know the temps are not near what they were with the OEM cover.
 
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