Ok so I added the transmission and differential temperature gauges along with the appropriate Mag Hytec pans. While I have seen transmission temperature range sheets I have yet to find one for differentials? I am also interested to see how much the temperature will increase when under tow from the added weight. So far the temperatures (trans. & diff.) are pretty much a mirror image of each other.
Agree with you that there isn't a lot said about it. I think that the conventional school of thought is that if you run synthetic gear oil in them, that the heavy metal on metal nature of them should make them more resiliant than more complex transmissions. More frequent gear oil changes (twice as often)are recommended for towing.
That said, I learned first hand that they do heat up. 2005-Present Jeep Grand Cherokees with 4WD vent the front diff right into the fresh air intake for air conditioning. After a few hundred miles of towing, the smell of sulfur lets you know that the oil is getting pretty hot in the front diff. Had the vent relocated away from the air conditioning intake and changed the fluid.
2010 Skyline Layton 190
2008 Jeep Grand Cherokee Overland 5.7L V8 4x4 3.73 Axles
Me, DW, daughter, Golden Retriever and Goldendoodle
The REASON not much is said is that it is rarely a problem. I've been towing for over 40 years and not ONCE did I ever know my differential temp. Never had one go out either. Good luck / skip
2004 F-250 SCREW Long Bed (new)
OR 2004 F-150 HD (85,000 towing miles) Rockwood 8314SS 34' travel trailer
We have enough YOUTH...how about a fountain of SMART
Probably about 150-160 solo and 180-200 while towing. Up a long steep grade may get a little over 200. Run a good synthetic and you will have no worries. The bigger cover will lower the temp slightly. What temp is it running at now?
On a brand new truck or differential, temps may get over 250 and even up to 300 degrees until broken in, one reason why it is a good idea to follow the manufacturer's recommendation and not tow for the first 500 miles to give the gears time to break in. On some trucks, you will see half of the diff cover rusted, this is where the paint burned off from the incredible heat of the oil.
On my last TV, I installed the Mag-hytec diff cover and digital gauges which gave more detailed info. The sensor in the M-h cover is located to collect hot oil coming off the gears so it will heat up and cool down very quickly. However, once the initial temp rise is over, under steady state conditions (towing or solo) there will be a small rise in temp over 1-2 hours as the mass of the rear axle slowly heats up. Diff. temp. while towing will directly reflect power consumption while towing. Under flat road, no wind conditions, towing temp will just barely be higher than solo temp under the same conditions. But hills and headwinds while towing, clearly produces higher diff. temps. If you assume that the diff. is maybe 95% efficient with the other 5% being heat, then the more power transfered thru the diff. the more heat generated. Highest temp. I observed on a long, steep grade was 245 degrees F. It's been a long time, but as I recall, even solo on flat roads, I could see an average temp. of about 160 degrees F.
Larry Day
Texas Baptist Men-Retiree Builders since '01
'03 GMC 2500HD D/A EC SB, Jordan controller, custom RKI bed/hitch, Putco boards, TF 45gal tank, grey Speedliner
'04 CrossRoads Cruiser CF29RK, Mor/ryde IS, Carefree Eclipse 12V awning Rig Photos
Diff fluid is the #2 most neglected auto fluid. #1 is the power steering
fluid.
In a perfect world, there would be no need for any kind of lube, as there
would be no friction or any other losses
Nor would there be any people who over load and abuse their stuff
Lube is designed in. It's weight, additives, etc.
No different from engine oil, tranny oil, coolant (it is also a lube)
and whatever else has lube
Lube of this kind is to float the gear teeth faces from ever touching
each other. There should be a film of oil that the two gear teeth faces
rides on. There should be no metal to metal contact, but there is
from time to time. More so when over the ratings of that gear set.
Notice that gear lube has 'EP' service, which stands for extreme pressure
Meaning it won't get squished out when within the design criteria
or specifications
In doing it's job, lube gets hot...that nasty friction at work. Hot
enough to oxidize (burn).
Why there are engine oil coolers (both inside the main radiator and
external), tranny oil coolers (both inside the main radiator and
external) and on some racers, diff coolers. Why there are also larger
capacity diff covers with fins. The added volume helps and the increased
surface area for heat rejection also helps....but does not solve an
over load condition. That is still there, just that the lube now has
a better fighting chance.
Not everyone needs, and/or knows that they need lube coolers.
All lube has a working specification and within that, a temp range
from cold to hot. The charts usually base themselves on this working
temp range. Along with that is the longevity of the thing it protecting
So the PMs and the OP, having a diff temp gauge only allows vision
into how the diff fluid is doing. Wont' save it in itself, but to
notify the driver that they are okay to overloading it or somewhere
in between.
As for what the temp should be, this one got me. Don't know and will
have to look that up. Won't look for a chart directly but for the
gear lube spec.
Here is a good reference manual for MDT (med duty trucks) that also
applies to our LDT (light duty trucks). Same thing, just our stuff
smaller. Boring read for those non-techie, but just look at the pictures
and then noodle that if these big boys can break from overload, then
of course our little guys can too.
Congrats to the OP for going the extra both in putting in the gage
and wanting to know the metrics of HOW2 manage it. I'll try to find
the temp range info and post it back here on this thread.
-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...
My Differential gauge gets up to 200-210 while towing up a hill whereas on the flats it runs 190 or so. Trailer is 7700 GVW and I have the Excursion V10. Not towing it runs much cooler say 160 or so. I have never used it solo on a trip so not real good numbers except when towing. I also have the mag hytec rear end cover with the sensor mounted on the top, not the middle of the back. There are 2 ports for the sensor.
Conventional gear oils should be good to about 280F. Mobil 1 75w140 is good to 430F. It is possible for them to start shearing and breaking down over time at lower temps however.
I'm running the mobil 1, but I have decided that id I ever see 280 I'm backing off the go pedal.
So far, nowhere even close. Surprisingly, my diff temp is mostly affected by speed. Total combined weight, outside temps, and hills don't affect it near as much as high speeds.
Bryan
2000 Ford E350 DRW Wagon (14-pass all captains chairs)
V10 w/ Banks PowerPack, Diablo Predator, 4.56 LS, 250,000+ miles
Had: Weekend Warrior 41' FSW
Mr. Obvious wrote: I also have the mag hytec rear end cover with the sensor mounted on the top, not the middle of the back. There are 2 ports for the sensor.
Actually the middle back port is the fill sight hole, not a sender hole. Threads are not the same. (I have one too).
Thanks all. Although I haven't had the opportunity to tow since installation (heading to Yosemite in a couple of weeks, up and over the grapevine)I am looking forward to reducing the temps. Flat land 20-30 minutes drive has given me about 160 degree reading.
I decided to make the swap due to the rusty cover as identified by one of you. I figured if the heat was enough to cook the paint of the cover I would be best to see what I could do.
I have had the tranny on a Mag Hytec for a couple of years and the highest temp was 240 when I came around a blind turn only to encounter a steep climb. I will say that as soon as I got to the top in about 2 minutes time the temp was back in the 180-200 degree range.
Some people may say I'm over reacting but I don't have nor would I want to spend the large $'s to repair something I can protect.
Offline
