Diff Question

jlemaire1 · November 29, 2009

the other day my rearend seemed to lockup.i was playing around and when the tires quit spinning i went to make a left turn and it felt like my diff had locked up.arter backing up and easing forward all seemed ok.should i be concerned or what do think caused this.it is on a 08 1500 w/373 gears and is a 4wd.when i was turning left it was at a crawl and i could feel the left tire skipping.and help would be appreciated.

alwcurlz · November 29, 2009

the other day my rearend seemed to lockup.i was playing around and when the tires quit spinning i went to make a left turn and it felt like my diff had locked up.arter backing up and easing forward all seemed ok.should i be concerned or what do think caused this.it is on a 08 1500 w/373 gears and is a 4wd.when i was turning left it was at a crawl and i could feel the left tire skipping.and help would be appreciated.

I had that same thing happen once. I have a 1999 GMT800 with the 373 rear end and it has the LSD function. Mine was locked up after I was at a light and some guy in a Ford Explorer Sport wanted to race so, when it turned green, I goosed it up to the speed limit. When I went to make my turn down the street, I felt the rear end grabbing. When I pulled into the driveway the tires were grabbing really good and scrubbing the blacktop off pavement pretty good. Was kinda aggravating because it wasn't disengaging. The next day I backed out and gave it a little surge and took off to work. When coming back home it was open. Not really confident in these rear ends hearing about the others that have had them come apart. These LSD rear ends are supposed to lock only when one wheel is spinning faster than the other which locks the two and then lets go afterwords. It's not a perfect science I guess and something we have to take it easy on. Kind of annoying.

jlemaire1 · November 29, 2009

the other day my rearend seemed to lockup.i was playing around and when the tires quit spinning i went to make a left turn and it felt like my diff had locked up.arter backing up and easing forward all seemed ok.should i be concerned or what do think caused this.it is on a 08 1500 w/373 gears and is a 4wd.when i was turning left it was at a crawl and i could feel the left tire skipping.and help would be appreciated.

I had that same thing happen once. I have a 1999 GMT800 with the 373 rear end and it has the LSD function. Mine was locked up after I was at a light and some guy in a Ford Explorer Sport wanted to race so, when it turned green, I goosed it up to the speed limit. When I went to make my turn down the street, I felt the rear end grabbing. When I pulled into the driveway the tires were grabbing really good and scrubbing the blacktop off pavement pretty good. Was kinda aggravating because it wasn't disengaging. The next day I backed out and gave it a little surge and took off to work. When coming back home it was open. Not really confident in these rear ends hearing about the others that have had them come apart. These LSD rear ends are supposed to lock only when one wheel is spinning faster than the other which locks the two and then lets go afterwords. It's not a perfect science I guess and something we have to take it easy on. Kind of annoying.

well i appreciate the response.didn't know if it was an isolated incident or not.thanks alot.thinking about getting a 09 2500 so i won't have to worry about spinning the tires.

zedbear · November 29, 2009

Not sure if 08's are anything like 00's back there but I thought the rear end might be focked up on mine. Was "skipping" and dragging and making a horrible noise when I pulled out of a parking spot for example. Found the clip that holds the parking brake shoe to the backing plate was gone and the shoe was sticking out at the bottom and catching on the drum part of the disc.

96chevy7.4L · November 29, 2009

If you have the G80 RPO code in your glove box lid you have the Eaton Locking Diff. In that case it might be the centrifugal weights not being thrown out to unlock the rear end. There are clutches in there that help to lock it in also. Might be time for a differential fluid change. Just my opinion.

alwcurlz · December 3, 2009

Not sure if 08's are anything like 00's back there but I thought the rear end might be focked up on mine. Was "skipping" and dragging and making a horrible noise when I pulled out of a parking spot for example. Found the clip that holds the parking brake shoe to the backing plate was gone and the shoe was sticking out at the bottom and catching on the drum part of the disc.

The skipping/dragging is your LSD (Limited Slip Differential) engaging when it's not supposed to or it's breaking apart. Your parking brake shoe designed into the rear disc brake from the factory had a poor design where the brake shoe would move and lodge forward and drag on the drum while dis-engaged and prematurely wear out the pads. If you go and buy new shoes/pads, make sure it has the extra parts which correct this problem that will holds the shoe in place properly.

atkinsonair · December 3, 2009

I wanted to add to this, i had my 08 silverado rear stick after i spun the tires in the rain, wasnt on purpose but i had a time getting it to unlock. I accually spun my tires again and backed off and it unlocked.

dlstewart01 · December 3, 2009

Not sure if 08's are anything like 00's back there but I thought the rear end might be focked up on mine. Was "skipping" and dragging and making a horrible noise when I pulled out of a parking spot for example. Found the clip that holds the parking brake shoe to the backing plate was gone and the shoe was sticking out at the bottom and catching on the drum part of the disc.

The skipping/dragging is your LSD (Limited Slip Differential) engaging when it's not supposed to or it's breaking apart. Your parking brake shoe designed into the rear disc brake from the factory had a poor design where the brake shoe would move and lodge forward and drag on the drum while dis-engaged and prematurely wear out the pads. If you go and buy new shoes/pads, make sure it has the extra parts which correct this problem that will holds the shoe in place properly.

He doesn't have a limited slip. All trucks with a G80 have a locking diff. See GM Bulletin...

LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION) #91-4-109

SUBJECT: LOCKING DIFFERENTIAL (G80) LUBRICANT - (SERVICE INFORMATION)

VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS

Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.

This condition of alternate engagement and disengagement of clutches in differential assembly is usually caused by contaminated axle lubricant.

To correct this condition, drain and refill the rear axle with SAE 75W-90 GL5 (P/N 10950849). The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.VEHICLES/COMPONENTS INVOLVED: ----------------------------- Some light duty trucks equipped with locking rear axles, RPO G80.

SERVICE PARTS INFORMATION:

Part Number Description ----------- ------------------ 10950849 Lubricant, Rear Axle (1 litre)

Parts are currently available through CANSPO.

WARRANTY INFORMATION:

As specified in Light Duty Truck Maintenance Schedules, locking rear axle fluid drain and refill is required owner maintenance at the first engine oil change. Failure to drain and refill the rear axle as specified may contribute to a later axle chatter condition. Refer to the appropriate Light Duty Truck Maintenance Schedule or service manual, section OB, for further details on change intervals.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.

zedbear · December 11, 2009

Not sure if 08's are anything like 00's back there but I thought the rear end might be focked up on mine. Was "skipping" and dragging and making a horrible noise when I pulled out of a parking spot for example. Found the clip that holds the parking brake shoe to the backing plate was gone and the shoe was sticking out at the bottom and catching on the drum part of the disc.

The skipping/dragging is your LSD (Limited Slip Differential) engaging when it's not supposed to or it's breaking apart. Your parking brake shoe designed into the rear disc brake from the factory had a poor design where the brake shoe would move and lodge forward and drag on the drum while dis-engaged and prematurely wear out the pads. If you go and buy new shoes/pads, make sure it has the extra parts which correct this problem that will holds the shoe in place properly.

But I just said it WASN'T my rear end, lol. The left wheel was actually dragging a little and the shoe was making a loud noise. It was especially suseptable to this when it was damp outside. One night it stuck a little bit the whole way home from work and the rim was hot when I got home. It was indeed the left parking brake shoe. I removed it and it hasn't done it since. Still have to drill out the bolt for the hold down clip so I can get it all back together.

alwcurlz · December 14, 2009

Not sure if 08's are anything like 00's back there but I thought the rear end might be focked up on mine. Was "skipping" and dragging and making a horrible noise when I pulled out of a parking spot for example. Found the clip that holds the parking brake shoe to the backing plate was gone and the shoe was sticking out at the bottom and catching on the drum part of the disc.

The skipping/dragging is your LSD (Limited Slip Differential) engaging when it's not supposed to or it's breaking apart. Your parking brake shoe designed into the rear disc brake from the factory had a poor design where the brake shoe would move and lodge forward and drag on the drum while dis-engaged and prematurely wear out the pads. If you go and buy new shoes/pads, make sure it has the extra parts which correct this problem that will holds the shoe in place properly.

But I just said it WASN'T my rear end, lol. The left wheel was actually dragging a little and the shoe was making a loud noise. It was especially suseptable to this when it was damp outside. One night it stuck a little bit the whole way home from work and the rim was hot when I got home. It was indeed the left parking brake shoe. I removed it and it hasn't done it since. Still have to drill out the bolt for the hold down clip so I can get it all back together.

Drill out what hold down clip? You don't have to drill anything to get the parking brake shoe off or back on.