Carrier Assembly Getting Hot

[OldSalt]

Recently I have been getting heat in the rear carrier assembly on the rear axle, primarily around the rear bearing cage. Est temp around 200-250 deg (time to invest in an infra red thermometer), enough to generate steam when I washed the truck after a 10 mile drive at 50 mph. Time for a re-man unit?

 

[porkysplace]

Have you checked the gear-oil level ?

 

[OldSalt]

porky:

Yup, the oil level is good, going to drain and filter to look metal particles today, since I already planned on servicing it.

 

[73m819]

Any noise, you are NOT talking about the hub, but the third member

 

[OldSalt]

No, 73m819, no noise, though it is hard to hear anything over the turbo. The heat is in the upper part of the the carrier assy (3rd member).

 

[73m819]

any play in the pinon (back and forth or up/down

 

[OldSalt]

73m819, I'll have to check and get back with you on that one, last time I checked (500 miles ago) though, no.

 

[OldSalt]

No play what so ever, looking for movement in the pinion yoke.

 

[73m819]

after running long enough to bet things HOT, put your hand on the different bearing areas (both ends of the pinon, and both sides of the gear below it) see if one area is hotter then the rest

 

[OldSalt]

Did that when I noticed the heat buildup. The heat is relatively uniform throughout the ring and pinion portion of the 3rd member, and gets cooler as you move from that area. Not hot enough to need to remove your hand, but hot enough to raise some concern.

 

[Stalwart]

It doesn't take 200-250 to give the apperance of steam, 150 degrees will do it if the atmospheric conditions are right. Use the IR thermometer to verify. If you had actual audible sizzling then I'd be concerned. 3rd members do run hot, often simply the shearing action between the ring and pinion or a tight bearing set, but if you can touch it I wouldn't be too worried. You can't hold your hand on metal that is very hot, nowhere near 200.

 

[OldSalt]

Well, looks like I'm getting a new toy today, an IR thermometer. Thanks everyone for the help & advice.

 

[73m819]

If you say not hot enough to remove your hand, then I would say it's not 200-250 (when the hub got hot on the first try on my deuve trip, it was hot enough to leave a mark), I would wait to see what comes out in the oil, if all looks fine, I would keep an eye on things and run it.

Is this the first you noticed heat, have you checked before

 

[rosco]

Rule of thumb..... 150 F is about what you can hold your hand on, if you really grit your teeth. How does that temp compare with other components/differentials? 150 is NOT hot for a differential - on highway, summertime, normal pulling operations, they can and do run at 500F. If you stick your finger in the lube oil, in bright light, you would be able to see metal flakes (if present) - you don't have to drain it, to check that.

 

[OldSalt]

The gear oil looked great. This was the first time I noticed the heat, but never checked it before. I'll just run 'er and keep an eye on things. Thanks again for the help/info! Got to keep it in tip top shape, she's my favorite vehicle, a little expensive to fill up, but still the favorite.

 

[Stalwart]

UM . . . ER . . . NO! 500 degrees would coke the oil and make it smoke, they don't run that hot or the oil would burn. The flash point of gear oil ranges from 375-580 and you'd be loosing oil due to evaporation.