tires feathering

[banshee42096]

okay i asked this before but i need some help.

i have a 2004 gmc cc 44 2500hd with the locking diff.

my problem is wirh about 3000 miles on tires i noticed

the rear tires feathering.at about 4000 miles i replaced all 4 tires

with 265-16 goodyear at/s load e at about 7000miles i notice the

rear tires feathering again took to dealer said everything was fine

it was a tire issue.i took it to a goodyear dealer they checked and

stated it was the truck. now is this a major jerk off contest or what

.meanwhile i rotated the tires and of coarse the rears feathered again

.now i cant blame the tire because the stock ones did the same.

any help would be great . thanks

[millerwd]

Banshee, ths is interesting.

 

What type of driving do you do?

The reason I ask is i commute over a mountain pass. The road is two lane hiway fairly twisty with the occasional passing lane.

I drive it hard, 63 MPH +. At oh dark thirty (05:30) there isn't much traffic.

I have the stock Bridgestone 245s with 20k miles on them. I haven't noticed any irregular wear on fronts or rears. I haven't rotated them because I want to see which axle rears the most.

I usually run about 42-45 psi the tires are E rated and max psi is 80.

 

BillM

[banshee42096]

normal driving i dont realy beat on it that much.

back and fourth to work 45mph approx 25 miles

a day and weekends 75-80mph 500miles round trip

.no off roading yet.the only thing i can think is happening is

the locker is not disengagingaround turns or maybe a poss

bent axle shaft.i checked the alignmnet and the rear end is

good go figure.

[millerwd]

now that you mention it, the locker on mine is pretty stiff. At times when I'm turning sharp, at an intersection or in a parking lot the rear end just seams sorta bound up.

 

I have no idea exactly how the rear end works. It feels like it needs to disenage to make turns. I believe they're supposed to enage when one wheel is going faster than the other.

[SS Crew]

If your tires are feathering, try pumping up the pressure in the tires. If they're rated for 80psi, try 60 - 70 psi. I had the problem with wide tires on my '99. I was running 275-60-17s with no weight in the back. My previous experience had been to not pump the pressure to keep the tires from wearing in the centers, but the edges were feathering. My alignment guy told me with high pressure tires, they do not react well to low pressures. After I pumped them up, I had no more feathering problems. Hope this helps you.

[banshee42096]

i did have them at 55psi all around thats recommeded

for the fronts rear is 80psi just seems to high for the

rear without towing.hard ride may just be me

[Mort]

When I got my truck it had 45 all around. I like to keep it ready to go so I put 50 in the front and 80 psi in the rear. It is a little harsh but I like a firm tire so it doesn't really bother me. The tires are definately wearing faster in the middle of the tread than on the edges but I would rather have that than rounded worn over and scalloped edges.

I have the G80 as well and it seemed to drag a little when it was new but I don't notice it any more now that it is worn in.

I am not sure why your tires are feathering on the rear as that is really more of a problem that I associate with front tire wear. I suppose it is possible that the G80 is not fuctioning properly. If you suspect the differential it is not too hard to pop off the rear cover and do an inspection. Probably would not hurt to change out the fluid anyway. Just be sure to use a synthetic 75W90 gear oil and do not add any friction modifiers. The GM supplied fluid is probably the best because it is specially designed for that application.

Good luck figuring it out. Problems like these with no clear cut answer are always frustrating to diagnose.

[Chris97K1500]

Not sure, but under 20mph, the G80 works all the time, over 20, it disengages. Going slow through intersections when turning or in parking lots would explain why the rear end feels "bound up". Hopefully someone who knows for sure, but I think I'm right. Chris

[Shawn T]

The G80 should behave like an open diff under slow normal driving. One wheel spinning faster than the other should engage the locker in the rear end. I have helped a guy rebuild one on my OBS pickup. There is a tiny centrifugal clutch mechanism that has tiny weights on it. I works like a snowmobile clutch. As the diff spins it ingages and locks the rear end. After about 20 mph it overspinns and releases the clutch opening up the diff again. So manuvering through parking lots and upon take-off(without hard, tire spinning accerlation) the rear end should not feel "bound up". My experience with the G80 is alot of fluid maintenance. After 2500 miles the fluid needs to be changed completely from the addative based fluid that is in it from the factory. From there on out I changed mine every 6500 miles and it worked like a charm. No unusual tire wear or the "clunk" that some people experience. I am no expert by any means but, like I said, I watched a rebuild and that is how I interpreted the operation of the G80. Good luck.

[c502cid]

Funny you mention this but my new tires are feathering in the rear, but in the center! They are feathering to the rear no less. New Cooper snows, 265's, set at 52 lbs pressure. I maybe have 1000 miles on them just did a 80mph blast from Denver to Salt Lake. Any ideas?

[496 CUBIC INCHES]

Not sure, but under 20mph, the G80 works all the time, over 20, it disengages.  Going slow through intersections when turning or in parking lots would explain why the rear end feels "bound up".  Hopefully someone who knows for sure, but I think I'm right.  Chris

 

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You're pretty much wrong all the way around.

 

The G80 acts like an open diff until it senses one wheel spinning faster than the other. Its never locked all the time. The wheels must be going less than 20MPH for it to engage,but once locked it will stay locked way past 20MPH.

[banshee42096]

my rear tire are feathered all the way across not in any

certain areas thats whats real weird