'03 Z06 Differential function
Thread Starter
Heel & Toe
Joined: Jul 2009
Posts: 24
Likes: 1
'03 Z06 Differential function
I have a steep driveway, can just get up it without scraping when taken at an angle. The right front tire hits first, loading that corner's suspension. If I don't have enough speed, the right rear tire lifts off the ground and spins and the car moves backwards until the right rear hits pavement. If I unhook the front sway bar, the tire stays planted and there is no problem. Everyone says my diff is not working correctly. I blocked a front wheel, put in neutral and released parking brake. Then I jacked up both rear wheels, spun each wheel, the opposite side spun in the same direction. Then jacked just one wheel at time and felt great resistance to turning in either direction, but would turn. The car is stock, lowered 3/4" in front, 1/2" rear,
And both wheels lay down equal black marks under acceleration. Do the diff clutches not work until under acceleration? What is going on?
And both wheels lay down equal black marks under acceleration. Do the diff clutches not work until under acceleration? What is going on?
AMP Racing
Joined: Aug 2006
Posts: 10,758
Likes: 589
From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
It's normal...
The force to push the car uphill, is greater then the friction of the clutch packs in the diff and they can't hold.
Try applying a little bit of emer brake. That might help. Probably not, but maybe it will.
The other option is move to a different house.
Or, leave the sway bar off. These cars don't need it anyway unless you're on a road course track.
The force to push the car uphill, is greater then the friction of the clutch packs in the diff and they can't hold.
Try applying a little bit of emer brake. That might help. Probably not, but maybe it will.
The other option is move to a different house.
Or, leave the sway bar off. These cars don't need it anyway unless you're on a road course track.
Pro
Joined: Dec 2015
Posts: 662
Likes: 184
From: Knoxville TN
I have a super steep driveway also, I have to hit it at an angle and my drivers rear comes up off the ground I just hit it with enough speed to keep my momentum going, clutch it when tire off of the ground then get back into gas, you just have to time it correctly it will take a few tries but you will get used to it
I have been doing it this way a few yrs so I don't even think about it now just used to it but I cannot pull in normal without letting off the gas and clutching or it will stall out
I have been doing it this way a few yrs so I don't even think about it now just used to it but I cannot pull in normal without letting off the gas and clutching or it will stall out
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You have a few options:
1. Raise the car up until it can transverse the slope without contact.
2. DONT transverse the driveway.
Check the differential. Mine seemed fine until I took it apart and found damage. I too could leave two solid black marks BUT, they were not normal on the passengers side. They faded out before the drivers side and left weird centerline marks. I had a broken Beleview spring and worn differential clutch pack clutches.
Recommend that you jack up ONE wheel at a time. Put the trans in neutral, and rotate that off the ground wheel to see how much force it take to turn that wheel left and right.
Do that for BOTH wheels. They BOTH should break loose at very similar torques.
If one has significantly LESS torque resistance than the other,,, that's an issue.
Mine had a broken passengers side beleview spring and worn clutches on that side..
Heres the proof!
As the miles accumulate the clutches wear and it takes less and less to break the wheel away. Its really tough to breakaway a differential with new clutches in it.
Bill
1. Raise the car up until it can transverse the slope without contact.
2. DONT transverse the driveway.
Check the differential. Mine seemed fine until I took it apart and found damage. I too could leave two solid black marks BUT, they were not normal on the passengers side. They faded out before the drivers side and left weird centerline marks. I had a broken Beleview spring and worn differential clutch pack clutches.
Recommend that you jack up ONE wheel at a time. Put the trans in neutral, and rotate that off the ground wheel to see how much force it take to turn that wheel left and right.
Do that for BOTH wheels. They BOTH should break loose at very similar torques.
If one has significantly LESS torque resistance than the other,,, that's an issue.
Mine had a broken passengers side beleview spring and worn clutches on that side..
Heres the proof!
As the miles accumulate the clutches wear and it takes less and less to break the wheel away. Its really tough to breakaway a differential with new clutches in it.
Bill
Thread Starter
Heel & Toe
Joined: Jul 2009
Posts: 24
Likes: 1
Testing
I did perform the tests you suggested. The resistance was equal in both directions for each wheel (just one wheel jacked at a time, trans in neutral). This car has less than 15K, so I doubt there is much wear. I think everything is fine, except for my driveway. Thanks for the pics and advice.
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Drifting
Joined: Aug 2000
Posts: 1,601
Likes: 52
From: Jefferson City MO
This is normal. My driveway is much the same it seems and as others mentioned, just have enough momentum to carry you forward.
Folks often think that their "posi" rear end keeps both wheels spinning at all times. This is not true. Almost all cars or folks that say they have posi, really have limited slip, which is what the Vette has. If the resistance is greater than the clutch packs, it will allow one tire to spin without the other. The resistance you feel by manually turning it is the breaking point of the packs. The only option is to weld the spider gears, get a spool or install a selectable locker. Would not recommend welding or a spool if you make right or left hand turns though.
Now, if someone actually placed a selectable air or electric locker in the rear, that would be very cool!
Folks often think that their "posi" rear end keeps both wheels spinning at all times. This is not true. Almost all cars or folks that say they have posi, really have limited slip, which is what the Vette has. If the resistance is greater than the clutch packs, it will allow one tire to spin without the other. The resistance you feel by manually turning it is the breaking point of the packs. The only option is to weld the spider gears, get a spool or install a selectable locker. Would not recommend welding or a spool if you make right or left hand turns though.
Now, if someone actually placed a selectable air or electric locker in the rear, that would be very cool!