Gear oil temp ?

[TwinStick]

I'll throw down a stupid question or two:

Are you sure it is full? Typically a bearing that is running in an oil bath needs to be full to 1/3 of the depth of the roller, give or take. Being empty means not enough lube = heat.

Yes, it is full.

Are you sure it isn't overfilled? Too much oil means too much resistance = heat. In this case, I think some would leak out the breather.

It is "slightly overfilled", according to the factory, by 1/2 qt. Reason: Google Dodge axle failures & you get 430,000 hits in 0.48 seconds. Before i bought my first Dodge, I researched this. I was corresponding with 24 or 26 (it's been a while) people who bought their truck brand new, had no leaks, was filled to factory levels & seviced only by dealer, who had axle failures under warranty. Every single one of the "Official final Reports" were identical---"pinion bearing failure due to lack of lubrication". Well, if it was filled to the correct factory fill level & there were no leaks, how could this happen ???

What weight oil are you running? Have you plotted viscosity curves for that oil? Many oils can survive higher temps without loss of viscosity.

Running Factory Mopar full synthetic 75 w 90. Just had to have the rear locker actuator/tone ring replaced under warranty. I think it failed due to the heat.

It has been over 15 years since I worked with gear drive designs, but we used to figure that we had issues around 150 over ambient temp. IIRC.

Are you getting abnormally low mileage? If something is overheating your oil, it has to be dragging on your system to the point of noticeable.

It is a Power Wagon so, yeah, mileage is BAD. Always has been since new. 8-10 mpg. period. Less towing.

Have you lifted the rear end and spun the wheels by hand to see if everything moves freely?

Yes, they move by hand. I check that every time I rotate or switch tires from summer to winter.

I am as stumped as you. I did buy an analog & digital food thermometer & will check with those against the IR one in the next few days or so. Lots going on right now. Pouring rain today---finally, we need it here.

 

[Buliwyf]

Semi truck axles run cooler because their just plain better than consumer grade junk. Not a fair comparison. Our axles have way more friction in the gears. If the oil isn't getting cooked black, and the paint isn't flaking off the axle anywhere, or discolored metal, don't sweat it. At least not until 320 degrees. The axle temps listed in the OP are normal for a three brads of the trucks we run. You can't even cook bread at 320. That ain't hot. Axles don't have radiators, and are in a state of constant friction when towing. If your oil smells fine, it's fine. If you'd like, run the diff oil for 20,000 miles of towing, drain it and send it to a lab for testing. They'll tell you if it's burnt or not. But I haven't witnessed bad oil that wasn't obvious.

My Mustang's axle went from room temp to 270 degrees on a single run up to 180mph. Axles heat up. Also keep in mind, an unloaded truck cruising gently, isn't going to heat an axle up as much as a loaded one.

Oh, and lose the IR temp thingy. Aside from finding a dead cylinder on a diesel, they're pretty worthless. You can try flat paint to make the readings more consistent if you'd like.

 

[TwinStick]

Todays findings: Ambient air temp 74* when I started, 80* when i got back.

Verified the 74*with the IR http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-69465.html , the analog one http://www.walmart.com/ip/THERMOMETER-SSTL-INSTANT-READ/49056557 , and the other digital one http://www.walmart.com/ip/TAYLOR-9835-Food-Srvc-Thermometer-40-to-450-LED/41239867 . they all read within 2* of 74*F.

Trip was 25 miles there & 25 miles back. Camper was on, on the way there but not, on the way back. Speeds were 55 mph - 70 mph with & without the camper. I removed the 1/2qt of extra gear lube i put in the rear diff before I started the truck up for the day. It was at factory fill specs, with factory Mopar full synthetic fluid (according to the dealer anyways).

Temp on arrival with the camper: 170*F
Temp after 40 minutes of sitting: 140*F
Temp when I got home empty: 160*F
Verified with all 3 temp readers. IR on the outside lower cover. Other 2 actually in the oil by removing fill plug. I could not hold my hand on there for more than 2 seconds. all were within 2*F of each other.

Now, add in a 95*+ day, pulling long steep hills, 70-80 mph, for hours on end & you can see why temps get so high.

My Mag-Hytec cover should be here any day now. It will double the fluid capacity to 6 qts total. When I get it, it will be filled with Amsoil. I hope it significantly helps with the heat.

Stay tuned.

 

[TwinStick]

Today, new Mag-Hytec cover arrived. Took a run into town & back with factory cover & fluid. Got home & it read 130*F.

Removed factory cover & PCP diff cover. The rear locker mechanism was replaced by dealer 1000 miles ago & refilled with factory full synthetic fluid---they said. Inside of cover was covered in the silvery stuff you normally find inside. No metal pieces, just the fine silvery stuff. Locker magnet was covered. Took 10 Q-tips to clean it, also just a thin film of the silvery stuff on fill plug magnet. The factory gasket looked bad. The bottom of it (it is a metal gasket, covered in rubber, with two ridges in it to help seal & is reusable) where the fluid level would sit, was (what looked to be) melted. Rubber was coming off the metal. But just where the fluid level would be. Above the fill line, the gasket was fine. Is this normal or did it melt ? IHNIdea.

So, new cover went on & 6 qts of Amsoil went in. Up to fill level on dipstick. Took a trip into town & back. Temp read 130*F ??? Maybe this will only reduce heat while towing or working it hard ???
Hate to think that $300, double the fluid capacity & cooling fins do not make a difference. Time will tell. Camper will be ready for pick up in a week or so. I will check again then.

Stay tuned.

 

[TwinStick]

Double post delete.

 

[Stumpalump]

What Amsoil did you use? https://www.amsoil.com/shop/by-product/gear-lube/

 

[roamingbeast]

sounds like bearing failure to me

 

[OSV]

So, new cover went on & 6 qts of Amsoil went in. Up to fill level on dipstick. Took a trip into town & back. Temp read 130*F ??? Maybe this will only reduce heat while towing or working it hard ???
Hate to think that $300, double the fluid capacity & cooling fins do not make a difference.

the cooling fins and cover material/color should make a small difference, but all that the extra capacity will do is just take longer to heat up and longer to cool down.

if you pull the cover again, take clean pics of the wear area on the gear teeth.

 

[Mo4130]

Also just a thought......don't pull a camper up steep grades at 70-80 mph. All to often people don't drive their rig effectively, then when stuff goes bad they think it's because of faulty equipment.

 

[digitaldelay]

If you use your breaks a lot a diff should run cool but if you coast to stops or downshift they run hotter. Hotshots that pull with 1 ton trucks wear out the coast side of the ring faster than the driven because they use engine breaking on grades. That's how much harder coasting is than driving on a diff. That's also a good way to determine if you should change the lube more often.

Very interesting, I had no idea that's how that worked. I try to coast or engine brake whenever possible. Thanks for the heads up.

Jason


Sent from my SM-G920W8 using Tapatalk

 

[Buliwyf]

Today, new Mag-Hytec cover arrived. Took a run into town & back with factory cover & fluid. Got home & it read 130*F.

Removed factory cover & PCP diff cover. The rear locker mechanism was replaced by dealer 1000 miles ago & refilled with factory full synthetic fluid---they said. Inside of cover was covered in the silvery stuff you normally find inside. No metal pieces, just the fine silvery stuff. Locker magnet was covered. Took 10 Q-tips to clean it, also just a thin film of the silvery stuff on fill plug magnet. The factory gasket looked bad. The bottom of it (it is a metal gasket, covered in rubber, with two ridges in it to help seal & is reusable) where the fluid level would sit, was (what looked to be) melted. Rubber was coming off the metal. But just where the fluid level would be. Above the fill line, the gasket was fine. Is this normal or did it melt ? IHNIdea.

So, new cover went on & 6 qts of Amsoil went in. Up to fill level on dipstick. Took a trip into town & back. Temp read 130*F ??? Maybe this will only reduce heat while towing or working it hard ???
Hate to think that $300, double the fluid capacity & cooling fins do not make a difference. Time will tell. Camper will be ready for pick up in a week or so. I will check again then.

Stay tuned.

130 ain't even bath water.

 

[TwinStick]

I understand all this, I really do. I used to drive semi-trucks in the US Army, in Germany. But this is a 3500 lb camper here people. We used to tow a camper that weighed almost 6000 lbs with a friggin STATION WAGON, thats right, a car. We never even had a problem either. Slow on the hills but no overheating, ever. So, in my mind, a 3500 lb camper should not even phase a 3/4 ton truck. I also understand that 130*F is not an issue, but the 256*F seems high. And the 315*F reading that I got while towing our 10,500 lb toyhauler is definitely high. I find it odd that no vehicle manufacturer or gear oil manufacturer says what is "normal" diff oil temp & what is "towing" diff oil temp. That way, someone might be able to stave off a costly repair & avoid being stranded.

Hopefully the camper place will call soon & say our camper is ready for pickup (from warranty work) & I can get some more readings. Are my readings higher because I have 4.56's ? Do I need to drive 55 mph with 4.56's ? All things I hope to answer myself through trial & error & many temp readings. One thing I have observed already is: when taking temp readings, the bottom of pumpkin is always hotter than the top, by around 20-30*F. Is it because I have to stop to take a reading & the oil settles & the top cools down that quickly ? Regardless, this also makes me question putting a temp sending unit at the very top of diff. . I know the oil sloshes & gets flung around but can it cool (or can the steel cool) 20-30*F in the time it takes for me to jump out & get a reading ? Just trying to get a good understanding of all these things.

Stay tuned.

 

[proper4wd]

All this from no actual symptoms of an issue. No failures. Clean gear oil. Paranoia is a *****.

 

[Stumpalump]

All this from no actual symptoms of an issue. No failures. Clean gear oil. Paranoia is a *****.

"Bu but harbor freight said its hot"....He won't touch it, he won't spit on it, he won't show us the ring pattern, he won't tell us back lash and he runs piss thin pyramid sceme LT/car lube designed to get hyper gas milage out of a car. Next he hauls azz with a 10500 pound load not counting the wind drag. The bro dozer cover is nifty but did it even got hot enough to blow lube thru the seals? That and spit are the only thing I've ever heard of to determine if it's too hot with the exeption of NASCAR. He should at least use the 75-250 like they do or the 75-190 Amway if he buys the hype. Fwiw pyramid sceme oil is great for gas milage but sucks when it's pushed to the max. The cheap bastards won't pay for the good additives so it won't pass SAE testing. It's crap. Just like Royal purple was but at least they wised up and fixed their products. The additives harden the metal at high heat and friction points. Amway relies on it being already hardened by somebody else's oil. Don't believe? Put that crap in a new engine, ring gear or tranny and see how long it lasts. It's good base stock like the other high end guys use so it works but only as they advertised and not as the industry says it should work. A lot of desert guys tried it but only once.

 

[TwinStick]

Yeah, cause spit is so much more reliable than a thermometer. OK then, seeing as how you think you know everything, what oil should I be running in the rear diff ?

This is what is in there now: https://www.amsoil.com/shop/by-product/gear-lube/75w-90-long-life-synthetic-gear-lube/?code=FGRQT-EA

As far as pics, I did take them. But I have no idea how to post them on here. New phone, technologically impaired & 53 yrs old. My I.T. tech just got a job & moved out so.................