rear diff

chappy · September 19, 2001

Had a problem a few months ago where the rear diff overheated so much it vented, took it too dealer. He could find nothing wrong, 1000 miles later while towing my 5th wheel the pinion bearings failed requireing complete rear end rebuild. My 99 silerado is tow rated to 11000 pounds and my trailer weighs 10300 pounds loaded. I have used a laser thermometer to scan the diff temp. and it is running around 75 to 90 deg C. My question is this: Does anyone know what is considered a normal running temp. for synethic diff fluid.I sure don't want to repair it again.:angry:

chevy4x4trucks · September 19, 2001

Man, you're towing pretty close to the capacity. I don't know what I'd do, I mean, if anything fails chevy has to fix it because they rated the truck at 11,000 so you're not in the wrong. I don't know what to tell you. Someone's gotta know what to do.

DT10 · September 19, 2001

Mike,

I talked to the Eaton axle people on this subject. They stated that the differential should run about 250 deg. F max. for sustained running. Prolonged running above 300 deg. F will degrade the additives in the oil quickly. If you scanned the diff. cover with the IR thermometer, the temperature you read could be 15 deg. lower than the actual oil temperature. Still your temperature load sounds within limits. Pinion bearings have been known to fail even with proper lubrication. The retaining nut may have been too tight from the factory or there may have been metallic contamination from the gear wear in.

Good luck,

DT10

Zane · September 20, 2001

Quote from DT10, posted on Sep. 19 2001,2:17

Mike,

I talked to the Eaton axle people on this subject. They stated that the differential should run about 250 deg. F max. for sustained running. Prolonged running above 300 deg. F will degrade the additives in the oil quickly. If you scanned the diff. cover with the IR thermometer, the temperature you read could be 15 deg. lower than the actual oil temperature. Still your temperature load sounds within limits. Pinion bearings have been known to fail even with proper lubrication. The retaining nut may have been too tight from the factory or there may have been metallic contamination from the gear wear in.

Good luck,

DT10

Wow, you know your stuff!

Welcome both of you to the site!!!

DT10 · September 20, 2001

Mike, (aka, Chappy), I could not respond to your note for some reason so here goes. I "fished" the contact person from Eaton's vast website. Just go to Yahoo and search on Eaton Industries. If I still have the reply note from them, I'll try to post the address.

DT10

vhato · September 21, 2001

Eaton is a wonderful company. 24,000 miles out of my warranty on my 99 silverado z-71 I DESTORED my gears and diff. I called GM, complained, and E-mailed Eaton because of the cracked Governing Rod Sleeve in the Locker. I put another Eaton Locker in myself with new gears and a month later GM sent me a new diff too....In the Box.....last week Eaton Called me. (8 months after I changed it) and told me to sell the one in my truck and the free one from GM and they sent me another Brand New in the Box Eaton Locker. Now I have 3 Eaton Lockers. Anybody want one?????????????