broken posi?
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TECH Junkie
Joined: Nov 2001
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From: Chi-Town
broken posi? is there any way to tell if your posi is broken by jacking it up and spinning the tires?
in N-
one spins backwards and one spins forward when only one wheel is turned.
you can hold the driver wheel and turn the passenger wheel freely
you can turn both forward freely.
in P- one spins forward and one spins backards
you can hold one and not turn the other one forward.
in drive- i thought it had the same results as in N.
any of those help to determine if my clutches are gone?
in N-
one spins backwards and one spins forward when only one wheel is turned.
you can hold the driver wheel and turn the passenger wheel freely
you can turn both forward freely.
in P- one spins forward and one spins backards
you can hold one and not turn the other one forward.
in drive- i thought it had the same results as in N.
any of those help to determine if my clutches are gone?
Thread Starter
TECH Junkie
Joined: Nov 2001
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From: Chi-Town
Re: broken posi? i was having trouble seeing some smoke from the driver tire at the track. looked in my mirror and the passenger side looked like it was on fire there was so much smoke <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> .
could be just that the track was so sticky that it wasnt turning <shrug>
did it a few times and i got sideways trying to heat the nittos up when i put them on.
could be just that the track was so sticky that it wasnt turning <shrug>
did it a few times and i got sideways trying to heat the nittos up when i put them on.
TECH Senior Member
Joined: Nov 2001
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From: Lake Zurich, IL
Re: broken posi? When my posi went in my first diff I could spin the driver side wheel and it would spin both wheels (in reverse direction) but it would hit a point (where the teeth on the spider gears were gone) where it would clunk.. then it would free spin.
Also when taking turns I would a clunk (at first it was barely noticable, thought it was the exhaust banging, but as time passed it got worse and worse). Opened it up and there were several teeth sitting at the bottom.
Also when taking turns I would a clunk (at first it was barely noticable, thought it was the exhaust banging, but as time passed it got worse and worse). Opened it up and there were several teeth sitting at the bottom.
TECH Resident
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From: Aurora Il
Re: broken posi? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> in P- one spins forward and one spins backards
you can hold one and not turn the other one forward </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So in PARK the tires still spin?? So what happens when you put the car in Park? Sounds like it would roll back/forward... that would have to be one messed up rear end.
you can hold one and not turn the other one forward </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So in PARK the tires still spin?? So what happens when you put the car in Park? Sounds like it would roll back/forward... that would have to be one messed up rear end.
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From: HP Illinoiz
Re: broken posi? I may agree with the sticky track theory...
I thought my rear was gone when that happened to me a the track last year...but the next few times out..no probs...
This weekend at Route 66 I had the same problem...
Drivers side was turning but the passenger side wasnt turning as hard.. (shrug)...
Maybe mine is shot too? Maybe not...
I'm sorta planning on rotating the tires this weekend... I'll 'give em a spin' and see what happens...
I thought my rear was gone when that happened to me a the track last year...but the next few times out..no probs...
This weekend at Route 66 I had the same problem...
Drivers side was turning but the passenger side wasnt turning as hard.. (shrug)...
Maybe mine is shot too? Maybe not...
I'm sorta planning on rotating the tires this weekend... I'll 'give em a spin' and see what happens...
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Re: broken posi? http://www.howstuffworks.com/differential8.htm
sez the Torsen is only able to split torque
by a maximum ratio. So if you have one wheel
in the air, zero times that ratio is zero.
The Camaro Z/28 and SS have a 2.2:1 ratio.
So you get 2.2X the torque of the passenger
side wheel, which always spins first due
to torque lift, on the driver's side wheel.
If the passenger wheel spinning torque
times 2.2 exceeds the driver's side
breakaway torque, then that side will spin,
too. But static/kinetic friction ratios can
be well above 2:1, especially when you're
talking about tires that are meant to have
high static friction to the road. So, with a
non-preloaded, low torque split Zexel, you
may still be able to cook one donut at a time.
Old type posis has spring loaded friction
plates that gave you some zero-input lock,
and ramps that made slip- or input-proportional
increase in holding force. They limited the
slip to nothing, on some designs/setups,
when the plates got loaded. The Torsen is
a much looser limit - 2:1 torque, and the slip
is allowed to be whatever makes the maximum
torque split happen.
http://www.globalwest.net/torsen_tra...fferential.htm
mentions a T2-R that has a preload, so even in
conditions with one wheel having zero traction,
you'll still get some torque out the other side.
sez the Torsen is only able to split torque
by a maximum ratio. So if you have one wheel
in the air, zero times that ratio is zero.
The Camaro Z/28 and SS have a 2.2:1 ratio.
So you get 2.2X the torque of the passenger
side wheel, which always spins first due
to torque lift, on the driver's side wheel.
If the passenger wheel spinning torque
times 2.2 exceeds the driver's side
breakaway torque, then that side will spin,
too. But static/kinetic friction ratios can
be well above 2:1, especially when you're
talking about tires that are meant to have
high static friction to the road. So, with a
non-preloaded, low torque split Zexel, you
may still be able to cook one donut at a time.
Old type posis has spring loaded friction
plates that gave you some zero-input lock,
and ramps that made slip- or input-proportional
increase in holding force. They limited the
slip to nothing, on some designs/setups,
when the plates got loaded. The Torsen is
a much looser limit - 2:1 torque, and the slip
is allowed to be whatever makes the maximum
torque split happen.
http://www.globalwest.net/torsen_tra...fferential.htm
mentions a T2-R that has a preload, so even in
conditions with one wheel having zero traction,
you'll still get some torque out the other side.
Thread Starter
TECH Junkie
Joined: Nov 2001
Posts: 3,029
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From: Chi-Town
Re: broken posi? update:
i peeled out on a backroad with the nittos on. the driverside let a prominant 12" wide strip for quite a distance, and i didnt see the pas. side mark- my gf said she could see it, but i didnt. we didtn get out of the car and look, just drove past it a couple times.
tried stalling it up and doing it again- it looked like two marks were left, but we didnt go back and look.
i have my stock 2.73 rearend at my lake house so i tested it out. hold the driverside axle and you cant turn pas. one. if you turn the passenger axle the driverside spins the same way- both of these did not happen when i tested mine <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />
dan- i think all rearends spin if its in park.
it grinds a little when turning left only- i just never really thought anything of it...im afraid to look inside.
i peeled out on a backroad with the nittos on. the driverside let a prominant 12" wide strip for quite a distance, and i didnt see the pas. side mark- my gf said she could see it, but i didnt. we didtn get out of the car and look, just drove past it a couple times.
tried stalling it up and doing it again- it looked like two marks were left, but we didnt go back and look.
i have my stock 2.73 rearend at my lake house so i tested it out. hold the driverside axle and you cant turn pas. one. if you turn the passenger axle the driverside spins the same way- both of these did not happen when i tested mine <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />
dan- i think all rearends spin if its in park.
it grinds a little when turning left only- i just never really thought anything of it...im afraid to look inside.
Thread Starter
TECH Junkie
Joined: Nov 2001
Posts: 3,029
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From: Chi-Town
Re: broken posi? peeled out today and it left two 12" strips <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> .
could it be half broken- sometimes engage and sometimes not? it seems to be getting louder <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
could it be half broken- sometimes engage and sometimes not? it seems to be getting louder <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />