my ZF box is not a LSD, is that right ? or is my lsd that stuffed ??
I thought they were all LSD
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LSD is a standard feature of the ZF in your car.
They are wierd in that if you jack the car up and attempt to turn the rear wheels, often it will uncouple itself from the opposite wheel and only one might turn.
In that regards it seems to acts like a "Detroit-locker" but it it a clucthing devise, unlike the Detroit-locker. It only works with the tires on the ground.
The gearbox is similar. If you try to run through the gears jacked up, it usually will like to grind the gears. It doesn't like that.
I think that the synchros and other internal devices need the resistance on the output side of the box to work properly. Without resistance it just won't work right. I suppose you need to ask ZF why. I can't explain it.
They are wierd in that if you jack the car up and attempt to turn the rear wheels, often it will uncouple itself from the opposite wheel and only one might turn.
In that regards it seems to acts like a "Detroit-locker" but it it a clucthing devise, unlike the Detroit-locker. It only works with the tires on the ground.
The gearbox is similar. If you try to run through the gears jacked up, it usually will like to grind the gears. It doesn't like that.
I think that the synchros and other internal devices need the resistance on the output side of the box to work properly. Without resistance it just won't work right. I suppose you need to ask ZF why. I can't explain it.
Ok thanks,
well perhaps it is a LSD, as when the wheels were off the ground one span forwards one span backwards as you said.
well perhaps it is a LSD, as when the wheels were off the ground one span forwards one span backwards as you said.
quote:Originally posted by v8capri:
my ZF box is not a LSD, is that right ? or is my lsd that stuffed ??
I thought they were all LSD
This is your trans on drugs....
Try mushrooms if LSD is toooo much for your ZF 
perhaps, i'll put some lighting and some pink floyd on the cd and see how that goes!!
Tangerine Dream is good with LSD.
( Some might say it only sounds good with LSD
)
Also, any diff will turn the other wheel backwards. If the propshaft is unable to turn the other wheel will mirror the movements you make. I've seen this many times when changing brake shoes on rear axles.
But you do have an Limited Slip Differential - they all have them. After 30 years of use it might not do much, but you definately have one.
( Some might say it only sounds good with LSD
)Also, any diff will turn the other wheel backwards. If the propshaft is unable to turn the other wheel will mirror the movements you make. I've seen this many times when changing brake shoes on rear axles.
But you do have an Limited Slip Differential - they all have them. After 30 years of use it might not do much, but you definately have one.
Rapier, the LSD on US built cars will turn both wheels in the same direction. Examples Ford Traction-lok, GM Posi-traction.
LSD being defined as a clutch operated limited slip system for the left rear tire. The left tire in US cars will generate about 85% of the drive of the right when new.
As the clutches wear, it transfers less and less.
The Detroit-lockers, as used in the '65 Shelby GT350, are a ratcheting locking device that transfers drive from one side to the other, not both.
The ZF, all though indicating that it is of the clutched limited slip design, seems to react like the Detroit locker does, but with clutches.
When both tires are off of the ground it seems to search for the drive wheel and often will confuse onlookers to mimic some traits of an open differential.
If I am not mistaken off the ground the ZF left tire just doesn't turn when the right does, as opposed to turning opposite in an open differential.
The test for correct locking pressure for a US limited slip would be to keep the right tire on the ground, jack the left tire and read the amount of force necessary to turn the wheel. The desired number should be around 185 ft-lbs.
The ZF doesn't seem to want to do that.
Confusing isn't it? It shouldn't be but it is?
LSD being defined as a clutch operated limited slip system for the left rear tire. The left tire in US cars will generate about 85% of the drive of the right when new.
As the clutches wear, it transfers less and less.
The Detroit-lockers, as used in the '65 Shelby GT350, are a ratcheting locking device that transfers drive from one side to the other, not both.
The ZF, all though indicating that it is of the clutched limited slip design, seems to react like the Detroit locker does, but with clutches.
When both tires are off of the ground it seems to search for the drive wheel and often will confuse onlookers to mimic some traits of an open differential.
If I am not mistaken off the ground the ZF left tire just doesn't turn when the right does, as opposed to turning opposite in an open differential.
The test for correct locking pressure for a US limited slip would be to keep the right tire on the ground, jack the left tire and read the amount of force necessary to turn the wheel. The desired number should be around 185 ft-lbs.
The ZF doesn't seem to want to do that.
Confusing isn't it? It shouldn't be but it is?
Yes, I should have written 'all non LSD diff will turn the other wheel backwards'.
I have often wondered a 'detroit locker' was.
What happens when it is very worn - do you end up with one wheel drive?
I am familiar with the concept of a 'limited slip differential' where the two sides are connected by aclutch or viscous coupling so there is always some drive to both sides. Like a standard diff unit with a clutch in the middle connecting the two drive shafts.
I'm not familiar with a locking differential - I shall do more reading. Thanks.
I have often wondered a 'detroit locker' was.
What happens when it is very worn - do you end up with one wheel drive?
I am familiar with the concept of a 'limited slip differential' where the two sides are connected by aclutch or viscous coupling so there is always some drive to both sides. Like a standard diff unit with a clutch in the middle connecting the two drive shafts.
I'm not familiar with a locking differential - I shall do more reading. Thanks.
The Detroit-lokcker has no clutches in it. It has interlocking plates that are engauged by a spring.
It doesn't really wear out.
Most get replaced because the owner can't stand them.
I remember a story about a friend that had a 66 Shelby GT350 with one in it. Just after they had gotten it, his wife took it to the Super Market (it was their daily transportation then).
She began to back the car up and thud...great she thought, I just backed into something. She gets out of the car and walks around it and there isn't anything within 20 feet of her. Lockers are like that.
I remember a day when I was coming home in my GT350 and the last turn for home was a 90 degree left hand turn at a stop light.
Well this day the light was out and a motorcycle cop is directing traffic. No problem right?
Well the locker is famous amongst other things for locking the inside wheel. Now if you think about it this is the opposite from what should happen right? The outside tire should be locked.
Well, I knew this was going to happen and I make my full stop waiting for direction from this nice police officer.
He sees my signal and waves me on. Don't you think that the locker causes a scene? It locks the inside tire causing not only that tire to churp, It sounds like the rear breaks or runs over a garbage can or a police motorcycle and leaves a steak of tire rubber and smoke for about 100 feet.
If that cop would have had Supermans x-ray vision, I'd be dead now.
But this is just the normal operating actions of th Detroit-locker. You gotta luv 'em but mostly I hate them.
Exactly how the ZF rear is intended to operate is confusing to me. It SEEMS to have this same type of locking, unlocking action, but with clutches. I just don't get how it works?
It doesn't really wear out.
Most get replaced because the owner can't stand them.
I remember a story about a friend that had a 66 Shelby GT350 with one in it. Just after they had gotten it, his wife took it to the Super Market (it was their daily transportation then).
She began to back the car up and thud...great she thought, I just backed into something. She gets out of the car and walks around it and there isn't anything within 20 feet of her. Lockers are like that.
I remember a day when I was coming home in my GT350 and the last turn for home was a 90 degree left hand turn at a stop light.
Well this day the light was out and a motorcycle cop is directing traffic. No problem right?
Well the locker is famous amongst other things for locking the inside wheel. Now if you think about it this is the opposite from what should happen right? The outside tire should be locked.
Well, I knew this was going to happen and I make my full stop waiting for direction from this nice police officer.
He sees my signal and waves me on. Don't you think that the locker causes a scene? It locks the inside tire causing not only that tire to churp, It sounds like the rear breaks or runs over a garbage can or a police motorcycle and leaves a steak of tire rubber and smoke for about 100 feet.
If that cop would have had Supermans x-ray vision, I'd be dead now.
But this is just the normal operating actions of th Detroit-locker. You gotta luv 'em but mostly I hate them.
Exactly how the ZF rear is intended to operate is confusing to me. It SEEMS to have this same type of locking, unlocking action, but with clutches. I just don't get how it works?