Hot Rear Differential ??

[Had2HavDMAX]

Occasionally I've been getting a hot smell from my rear wheels. Originally thought the calipers might be sticking ,dealer checked, all ok. Today after towing 9,000# the hot smell was present and also my rims were extremely hot especially the right side. The smell seems too be rear diff. fluid. (amsoil syn.) But the amount of heat being thrown off can't be good. I can feel it a few in. away from the rims and also can hear a ticking from the inside of the rim like something is cooling down. Towing about 800 miles this weekend so some quick suggestions would be greatly appreciated. Thanks

[dmaxalliTech]

axle seal leaking? Heat could be from brakes? Might want to check the axle seal to be sure

[David Proske]

You might want to crawl under there and see how hot the diff cover is. If the gear is getting that hot then something is wrong. How hot are the front brakes compared to the rear?

[Had2HavDMAX]

Brakes rotors are "burn your fingertips hot" I told this to the dealer but they checked all 4 wheels and said everything was fine.I have only gotten the burning smell when towing. The Differential cover is warm but not too hot too touch. Scary how hot the rim was !! Thanks

[poorloser]

Has anyone put an oil cooler on the rear differential?? I monitored the temp on mine while towing 12000lb. 5th wheel trailer. On flat ground it never went over 200 but on 6% grades it went over 260. What kind of pump?

[a64pilot]

Brake rotors can easily be scorch your fingers hot even with an empty truck. They work by converting kinetic energy into heat and there is a lot of kinetic energy in our trucks, real heavy. To eliminate a stuck or dragging brake drive the truck at moderate speeds for five or ten min. or so and then coast to a stop without using the brakes, all four rotors may be warm to the touch as there is always some brake drag but none of them should be real hot. BTW they should all be about the same temp. The rear end or pumpkin or chunk or whatever you call it should IMHO never be so hot that you cannot leave your hand on it, unless towing real heavy or going real fast etc. If these things are not too hot then the only things left that I know of are wheel bearings or underinflated tires.
poorloser,
I think that Broker has, but I know nothing about his set up.

[Buck]

had2hav

I had the same problem a while back. I went through and checked the brakes on my trailer and readjusted the brake controller. Seems that I had the brake controller set a bit to weak. It doesn't take much. When the truck's brakes get hot it takes a looong time for them to cool off. Maybe a Prodigy is in order for me :confused: I really don't like this draw-tite thing. It does work, but needs to be fine tuned every tow/weight change.

[GMC D-Max]

Noticed the same thing, Had2HavDMAX.
Check this thread:

http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=7&t=004793&p=

[retiredalaskan]

I had the same problem last year on a trip to new england. Had my camper on and towing my boat, blow a right rear tire. Long and short of it the emergency brake came loose inside the drum it was draging enough that it got VERY hot.and blew tire. Also took taking it to several dealers before one knew were to look for the problem. So check your emergency brake...

[Had2HavDMAX]

Just returned from 8oo mile trip. No excessive heat or smell pulling 3,500# entire time @ 7o mph. How do I check to see if axle seals are leaking? Sholud I change the rear diff. fluid? Thanks

[needbigtruck]

A buddy of mine has a 2001 6.0 2500HD and had the overheating brake thing (on the rear). Dealer told him the brakes had hung up due to not being cleaned, Whatever that means. The hot brakes melted the seal and his differential fluid was leaking out and that was what was smoking. The seal was replaced under warranty, but he had to pat to have all 4 brakes cleaned and adjusted. Dealer told him it is a yearly maintenance thing, I couldn't find it in the book. They told him it was a GM reccomendation. I don't really know what cleaning and adjusting means on disc brakes. Any takers?

[Dave Lewis]

I have heard from GM techs that you need to use your emergency brake all of the time. This helps keep things from rusting and locking up. They said most of the people who have problems with their rear brakes are the ones who never use the EB.

[BROKERS]

Do search,i have dicussed this issue a few times and i have descibed my cooler set up.I burnt up 3 rear gears. Good luck!

[AlanL]

RE: Using the e-brake

I use mine almost every time I park the truck. My alli is sometimes really hard to get into gear if its been resting on the park prawl.

I figured I was just saving the transmission... who knew that I was doing good things for the brake system, too??

[Burner]

Had2Have, Perhaps you should invest in a "non contact" sensor. Go down to the local contractors store and purchase a Fluke or something that will give you a heat reading. All you have to do is pint and shoot. You can test your front rotors and then the back. The back should be just a little cooler. You can also test your chunck during different pulls. If you can find another DMAX, at fuel station or somewhere, you could test that one against yours. If one side of the axel has bad bearings, it will be hot or hotter than the good side. tongue.gif

If you have never changed the dope, do it now. I suggest using the GM grape juice or Mobile One dope.


Burner------> :D

[D-MAX]

Maybe you need a Rear End Oil Cooler, like "Broker"

[dmaxalliTech]

it is a good idea to use the e-brake once and a while, but it wont do didly for your normal brakes. its seperate all togather. The e brake is just a small drum brake set up very similer to trailer brakes, cable pulls cam, expands shoes into drum in rotor. There is no maint for disk brakes exept maybe cleaning the caliper slides, drum brakes they needed to be cleaned and adjusted up once and a while.

Dave Lewis, that was true.... years ago. :D

[Had2HavDMAX]

Turns out that the axle seal was leaking which caused the emergency brake shoe to overheat and malfunction. They replaced the seal and the E brake shoes. The second dealer I took it to discovered the leak,strange how the first one didn't. Thanks for the replies/ suggestions.