Can a Locker cause this slop?
Thread Starter
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Fleet Mechanic
Joined: Sep 2009
Posts: 1,572
Likes: 37
From: Northern Virginia.
Can a Locker cause this slop?
i have a 1979 f-150 4X4.
it seems that the rear axel has slop in it. if i get under the truck
and grab the drive shaft it has about 1/2 inch of play ( twisting ) before it seems to start to turn the rear wheels. i checked the u-joints they seem
to be firm. look fairly new. no play in them at all. When turning the
drive shaft with my hands you see the entire shaft move as one but feel
like the pinion gear hits the tooth on the ring gear. i can grab the
drive shaft and all is tight. u-joints are good no slop in it. i know it has a
locker, just do not know what kind or type. if i turn tight either way
the inside tire chirps unless i am real easy on the gas. the tires are
38.5 x 15.5 X 15. how can i tell if it has a locker besides turning tight
and hearing the inner tire squeel. i can not take it apart if thats the
only way. not untill i have a lot more time.
Thanks.
it seems that the rear axel has slop in it. if i get under the truck
and grab the drive shaft it has about 1/2 inch of play ( twisting ) before it seems to start to turn the rear wheels. i checked the u-joints they seem
to be firm. look fairly new. no play in them at all. When turning the
drive shaft with my hands you see the entire shaft move as one but feel
like the pinion gear hits the tooth on the ring gear. i can grab the
drive shaft and all is tight. u-joints are good no slop in it. i know it has a
locker, just do not know what kind or type. if i turn tight either way
the inside tire chirps unless i am real easy on the gas. the tires are
38.5 x 15.5 X 15. how can i tell if it has a locker besides turning tight
and hearing the inner tire squeel. i can not take it apart if thats the
only way. not untill i have a lot more time.
Thanks.
Elder User
Joined: Jun 2003
Posts: 686
Likes: 1
From: Edgewood, Wa
Yes. I have a Powertrax Lock right in my 9" and in the book it says that 15 to 25 degrees of lash is normal. Meaning, I get a light clunk when letting up off gas, and a light clunk when I stab it again.
To see if it is a locker, jack up the rear end, put truck in Neutral, and rotate rear tires. If both spin the same direction, it's a locker ( OR a limited slip of some sort) if one spins one way and the other side is opposite, you have an open diff.
To see if it is a locker, jack up the rear end, put truck in Neutral, and rotate rear tires. If both spin the same direction, it's a locker ( OR a limited slip of some sort) if one spins one way and the other side is opposite, you have an open diff.
Post Fiend
Joined: Jul 2006
Posts: 6,948
Likes: 44
How is a locker going to create a greater amount of lash between the ring gear and the pinion gear? Its impossible.
When "lash" is greater than the recommended amount, the pinion will crash into the ring gear when torque is applied after a static stop, this will shatter the gears.
Something is wrong with the set up.
Lifting the wheels off of the ground and turning one tire is not always the proper indicator. Many lockers require a given difference in wheel speed in order to lock. Otherwise that are in a ratchet or unlocked mode.
Turning the wheels by hand will not activate some lockers.
When "lash" is greater than the recommended amount, the pinion will crash into the ring gear when torque is applied after a static stop, this will shatter the gears.
Something is wrong with the set up.
Lifting the wheels off of the ground and turning one tire is not always the proper indicator. Many lockers require a given difference in wheel speed in order to lock. Otherwise that are in a ratchet or unlocked mode.
Turning the wheels by hand will not activate some lockers.
Thread Starter
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Fleet Mechanic
Joined: Sep 2009
Posts: 1,572
Likes: 37
From: Northern Virginia.
Thanks for the help!!! i read on line that detroit lockers have some play before they
actually move the wheels even though the backlash is set properly. i will have to have
someone here in town check it out. i need to find a shop i can trust.
actually move the wheels even though the backlash is set properly. i will have to have
someone here in town check it out. i need to find a shop i can trust.
Senior User
Joined: May 2005
Posts: 131
Likes: 2
From: southern cal.
My Detroit locker ALWAYS did that. Also some times on starting out it would unlock with a scary loud clank and a swerve to the right. Transmission/diff. man said it was normal and you ought to try it in a Jeep for a thrill.
Elder User
Joined: Jun 2003
Posts: 686
Likes: 1
From: Edgewood, Wa
"lash" perhaps is the wrong term, were not talking ring and pinion here, were talking lockers, so "Backlash" would be correct.
Right from my PowerTrax book : "The Lock-right needs about 25 degrees of free drive shaft rotation to allow it to operate, producing a slight delay when getting on and off the throttle. This delay does not represent any problem with the assembly or with the drive gears. This built in backlash characteristic is present in ALL automatic lockers and is completely normal"
So, not impossible, but normal.
Right from my PowerTrax book : "The Lock-right needs about 25 degrees of free drive shaft rotation to allow it to operate, producing a slight delay when getting on and off the throttle. This delay does not represent any problem with the assembly or with the drive gears. This built in backlash characteristic is present in ALL automatic lockers and is completely normal"
So, not impossible, but normal.
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Thread Starter
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Fleet Mechanic
Joined: Sep 2009
Posts: 1,572
Likes: 37
From: Northern Virginia.
thanks for the info. i am going to check in to it some more. i feel a little better knowing it might be normal.
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Mountain Pass
Joined: Feb 2009
Posts: 159
Likes: 1
How is a locker going to create a greater amount of lash between the ring gear and the pinion gear? Its impossible.
When "lash" is greater than the recommended amount, the pinion will crash into the ring gear when torque is applied after a static stop, this will shatter the gears.
Something is wrong with the set up.
Lifting the wheels off of the ground and turning one tire is not always the proper indicator. Many lockers require a given difference in wheel speed in order to lock. Otherwise that are in a ratchet or unlocked mode.
Turning the wheels by hand will not activate some lockers.
When "lash" is greater than the recommended amount, the pinion will crash into the ring gear when torque is applied after a static stop, this will shatter the gears.
Something is wrong with the set up.
Lifting the wheels off of the ground and turning one tire is not always the proper indicator. Many lockers require a given difference in wheel speed in order to lock. Otherwise that are in a ratchet or unlocked mode.
Turning the wheels by hand will not activate some lockers.
he would have to pull the cover ans hold the ring gear still to test that.
the lash is the ring gear and pinion, and the locking device of the locker.
Detoit says over 10° at the locker, mulitply that by your ring and pinion ratio, and that is what you would see at the driveshaft.
Thread Starter
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Fleet Mechanic
Joined: Sep 2009
Posts: 1,572
Likes: 37
From: Northern Virginia.
just to clearify...
when twisting the driveshaft (truck in neutral ) the yoke mounted to the Axle from there to the np205. everything in between turns perfectly nice, uniform, no play, drive shaft does not move other than rotate.
i will try and pull the 3rd unit this weekend to see if it is bad. It cant be to bad besides some rusty old nuts n bolts.
when twisting the driveshaft (truck in neutral ) the yoke mounted to the Axle from there to the np205. everything in between turns perfectly nice, uniform, no play, drive shaft does not move other than rotate.
i will try and pull the 3rd unit this weekend to see if it is bad. It cant be to bad besides some rusty old nuts n bolts.
Mountain Pass
Joined: Feb 2009
Posts: 159
Likes: 1
just get a pic of the carrier so it can be ID'd
no reason to pull it if it has a locker in it
if anything that isnt enough play for a locker with deep gears
a detroit with 4.88s would have almost a quarter turn of the driveshaft worth of slop in it.
no reason to pull it if it has a locker in it
if anything that isnt enough play for a locker with deep gears
a detroit with 4.88s would have almost a quarter turn of the driveshaft worth of slop in it.
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