BACKLASH
Lead Driver
Joined: Jul 2017
Posts: 9,606
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From: San Jose, CA
Depends. What are we talking about? The rear differential? If so, which type of diff is it?
Yes, for any that's too much by far! So you're right to question it. But I've driven around on 9" diffs with up to 1/2" of backlash felt at the pinion yoke and they worked great with no noise and no apparent harm.
But because it's only supposed to be a few thousandths of an inch, I fixed it anyway. And sure enough, the new one only had a few thou of spin to it after it was done. So yes, the old one was way out of spec and worn severely. But again, it worked fine that way for longer than I care to admit.
paul
Yes, for any that's too much by far! So you're right to question it. But I've driven around on 9" diffs with up to 1/2" of backlash felt at the pinion yoke and they worked great with no noise and no apparent harm.
But because it's only supposed to be a few thousandths of an inch, I fixed it anyway. And sure enough, the new one only had a few thou of spin to it after it was done. So yes, the old one was way out of spec and worn severely. But again, it worked fine that way for longer than I care to admit.
paul
Fleet Mechanic
Joined: Apr 2012
Posts: 1,275
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If it's all in the pinion, ring gear, that's a lot, but if you ad in, spider gear slack, and include the axel spline wear both to the axel and spider gear splines, you can come up with more play than looks good.
Lead Driver
Joined: Jul 2017
Posts: 9,606
Likes: 1,175
From: San Jose, CA
And if it’s a Detroit locker, all bets are off unless you know how to tell the difference between gear backlash and other backlash.
Which might not be as hard as I make it sound, but it seems like I remember Detroit lockers adding some mysterious play to differentials.
Which might not be as hard as I make it sound, but it seems like I remember Detroit lockers adding some mysterious play to differentials.
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Fleet Mechanic
Joined: Apr 2017
Posts: 1,391
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From: COSMOS
I got an open diff ( one wheel pulls )........So is it worn out or need to be shimmed or what.......thankx al so very much.............I must sleep now
I WILL SLEEP BETTER NOW BECAUSE OF YOUR HELP..........
GOOD nITE
I WILL SLEEP BETTER NOW BECAUSE OF YOUR HELP..........
GOOD nITE
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Fleet Mechanic
Joined: Apr 2017
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From: COSMOS
To be more clear, when I spin back wheel it moves an inch before the driveshaft moves. I considered this backlash. I maybe wrong !!! 
A friend says it may be the universal joint..........That sounds better than something in side the differential.........
What u guys think........????????
A friend says it may be the universal joint..........That sounds better than something in side the differential.........
What u guys think........????????
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Lead Driver
Joined: Jul 2017
Posts: 9,606
Likes: 1,175
From: San Jose, CA
What 85e150 said. If it ain't broke, don't fix it. At least not yet...
That said, it sounds like it's not right anymore, so if you want to make it right again you will need to go deep into it and locate any worn items and replace and re-set them.
It's a can-o-worms and a very big process for those that have not done one before, but not that bad for those that have done it many times.
But once you dig it all out, you need to be ready to buy new ring and pinion gears, bearings, shim packs, seals, gaskets and all the rest. New ring gear bolts are not out of line either.
Some full rebuild kits come with everything you need except the expertise to install them.
And don't forget that if you don't know the history of the rear end, and have not done any work on it yourself, now is the time to replace the rear wheel/axle bearings and seals (if separate) and maybe even renew the brakes if they are worn close enough that you can save yourself the task of doing it again in a year or two.
So is this a Ford 9" differential? Or is it a Dana rear setup? Both are completely different in their method of fixing, but all the same basic theories apply.
Paul
That said, it sounds like it's not right anymore, so if you want to make it right again you will need to go deep into it and locate any worn items and replace and re-set them.
It's a can-o-worms and a very big process for those that have not done one before, but not that bad for those that have done it many times.
But once you dig it all out, you need to be ready to buy new ring and pinion gears, bearings, shim packs, seals, gaskets and all the rest. New ring gear bolts are not out of line either.
Some full rebuild kits come with everything you need except the expertise to install them.
And don't forget that if you don't know the history of the rear end, and have not done any work on it yourself, now is the time to replace the rear wheel/axle bearings and seals (if separate) and maybe even renew the brakes if they are worn close enough that you can save yourself the task of doing it again in a year or two.
So is this a Ford 9" differential? Or is it a Dana rear setup? Both are completely different in their method of fixing, but all the same basic theories apply.
Paul
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Lead Driver
Joined: Jul 2017
Posts: 9,606
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From: San Jose, CA
Sorry, did not see the last post until after I'd replied again. Stupid computer sometimes takes forever to load images and posts from this site.
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
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Fleet Mechanic
Joined: Apr 2017
Posts: 1,391
Likes: 106
From: COSMOS
Sorry, did not see the last post until after I'd replied again. Stupid computer sometimes takes forever to load images and posts from this site.
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
Anyway I plan to add a trans-loc & 17" wheels so now maybe the time..........I will tell you the play in driveshaft soon..........Thank-you so very much.........
Thread Starter
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Fleet Mechanic
Joined: Apr 2017
Posts: 1,391
Likes: 106
From: COSMOS
Sorry, did not see the last post until after I'd replied again. Stupid computer sometimes takes forever to load images and posts from this site.
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
Anyway I plan to add a trans-loc & 17" wheels so now maybe the time..........I will tell you the play in driveshaft soon..........Thank-you so very much.........
Thread Starter
|
Fleet Mechanic
Joined: Apr 2017
Posts: 1,391
Likes: 106
From: COSMOS
Sorry, did not see the last post until after I'd replied again. Stupid computer sometimes takes forever to load images and posts from this site.
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
No, you can't tell backlash from that method. Too many variables.
To check externally you need to have the wheels on the ground, or locked in place, then twist the pinion yoke by hand. You can leave the driveshaft connected, but it might be easier sometimes to disconnect and get it out of the way.
With the "turning the yoke back and forth" method, you're more likely to eliminate other components and be able to feel just the backlash of the ring and pinion gears. You can't do it out at a wheel. At least not in most cases.
So try it by hand at the yoke and let us know what the difference in play is.
Paul
I guess this the backlash
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