Differential side yoke play?
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Everyone's always asking for numbers so I'm going to stick my neck out and post guidelines. If anyone has an opinion or thought go ahead and post so that we can use these numbers for future questions.
End play:
Less than .025 No problem
.025 - .050 Starting to wear, consider inspection
.050 - .100 Beyond normal cluth wear, possible clutch damage
and/or heavy stub axle wear. Needs attention
.100-.150 Excessive wear and/or damage. Needs immediate
attention.
.150 -.200 Severe wear and case damage
Mike
End play:
Less than .025 No problem
.025 - .050 Starting to wear, consider inspection
.050 - .100 Beyond normal cluth wear, possible clutch damage
and/or heavy stub axle wear. Needs attention
.100-.150 Excessive wear and/or damage. Needs immediate
attention.
.150 -.200 Severe wear and case damage
Mike
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Everyone's always asking for numbers so I'm going to stick my neck out and post guidelines. If anyone has an opinion or thought go ahead and post so that we can use these numbers for future questions.
End play:
Less than .025 No problem
.025 - .050 Starting to wear, consider inspection
.050 - .100 Beyond normal cluth wear, possible clutch damage
and/or heavy stub axle wear. Needs attention
.100-.150 Excessive wear and/or damage. Needs immediate
attention.
.150 -.200 Severe wear and case damage
Mike
End play:
Less than .025 No problem
.025 - .050 Starting to wear, consider inspection
.050 - .100 Beyond normal cluth wear, possible clutch damage
and/or heavy stub axle wear. Needs attention
.100-.150 Excessive wear and/or damage. Needs immediate
attention.
.150 -.200 Severe wear and case damage
Mike
Excellent info Mike. This is a common question and it is helpful to have someone with recognized, extensive experience commit to a guideline. This is good info to have when these guys come on here spouting that 1/4" of play is nothing to worry about as they have been running thiers like that for years and so have thier buddies with no issues.
This is good info to have when these guys come on here spouting that 1/4" of play is nothing to worry about as they have been running thiers like that for years and so have thier buddies with no issues.
I have over 90K miles on my never been opened differential with 1/4" play. I can lay down two black strips launched at 3500 rpm all day long. No noises from the rear. So, when will I expect to have severe wear and case damage? Somewhere north of 90K miles? That's a lifetime for cars built back in the day. I think our vettes are a lot more durable and reliable than what others would think. Just sayin'.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
I guess I'm just plain lucky and spouting. Anyone is welcome to come up here and have a look at my rear! I have over 90K miles on my never been opened differential with 1/4" play. I can lay down two black strips launched at 3500 rpm all day long. No noises from the rear. So, when will I expect to have severe wear and case damage? Somewhere north of 90K miles? That's a lifetime for cars built back in the day. I think our vettes are a lot more durable and reliable than what others would think. Just sayin'.
I have over 90K miles on my never been opened differential with 1/4" play. I can lay down two black strips launched at 3500 rpm all day long. No noises from the rear. So, when will I expect to have severe wear and case damage? Somewhere north of 90K miles? That's a lifetime for cars built back in the day. I think our vettes are a lot more durable and reliable than what others would think. Just sayin'.I was going to disagree with the level of attention required as the wear increased but feared that this would just touch off another round of 'road safety' debates. It would be nice if the reasons for wear could be determined without disassembly of the diff. The owner could then decide which repairs are required (if any) and with what level of urgency. Simple end play of a yoke doesn't mean much by itself.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
A differential with 1/4' of play at the sideyokes has one of 3 issues.
1. Badly worn yoke ends and/or center pin
2. Trashed, broken posi clutches
3. Broken or missing C clips.
Any of the above means there is debis in the case circulating through the bearings and gears. I have posted this numerous times yet get the same responses. There is no filter for this fluid. There is no where for these shavings, fillings and pieces to go other than continuously circulating throughout the differential bearings and gears. I really don't get why this concept is impossible for some people to grasp.
I will try to make it simple. Metal fillings, shavings and chunks do not lubricate well and cause continuous wear and damage when run between gears and bearings. It is not necessary for the reason for the play to be able to be determined without opening the case. The case needs to be opened and the rear end rebuilt if it is not destroyed beyond repair.
To the OP your fine.
1. Badly worn yoke ends and/or center pin
2. Trashed, broken posi clutches
3. Broken or missing C clips.
Any of the above means there is debis in the case circulating through the bearings and gears. I have posted this numerous times yet get the same responses. There is no filter for this fluid. There is no where for these shavings, fillings and pieces to go other than continuously circulating throughout the differential bearings and gears. I really don't get why this concept is impossible for some people to grasp.
I will try to make it simple. Metal fillings, shavings and chunks do not lubricate well and cause continuous wear and damage when run between gears and bearings. It is not necessary for the reason for the play to be able to be determined without opening the case. The case needs to be opened and the rear end rebuilt if it is not destroyed beyond repair.
To the OP your fine.
Last edited by 63mako; Jan 26, 2012 at 12:52 PM.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Excellent info Mike. This is a common question and it is helpful to have someone with recognized, extensive experience commit to a guideline. This is good info to have when these guys come on here spouting that 1/4" of play is nothing to worry about as they have been running thiers like that for years and so have thier buddies with no issues.
This is good info to have when these guys come on here spouting that 1/4" of play is nothing to worry about as they have been running thiers like that for years and so have thier buddies with no issues.It's really a pretty simple concept.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
A differential with 1/4' of play at the sideyokes has one of 3 issues.
1. Badly worn yoke ends and/or center pin
2. Trashed, broken posi clutches
3. Broken or missing C clips.
Any of the above means there is debis in the case circulating through the bearings and gears. I have posted this numerous times yet get the same responses. There is no filter for this fluid. There is no where for these shavings, fillings and pieces to go other than continuously circulating throughout the differential bearings and gears. I really don't get why this concept is impossible for some people to grasp.
1. Badly worn yoke ends and/or center pin
2. Trashed, broken posi clutches
3. Broken or missing C clips.
Any of the above means there is debis in the case circulating through the bearings and gears. I have posted this numerous times yet get the same responses. There is no filter for this fluid. There is no where for these shavings, fillings and pieces to go other than continuously circulating throughout the differential bearings and gears. I really don't get why this concept is impossible for some people to grasp.
If differential bearing or gear failure was a common problem and was associated with yoke wear as a root cause, you would have a good point.
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Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Not sure if your question is rhetorical or if you're actually looking for an answer. Much like the huge number of owners who drive around for years with large amounts of yoke end play and are oblivious to it until they happen to jack up the car for inspection, the same differentials operate successfully for years despite the metal shavings sitting inside.
If differential bearing or gear failure was a common problem and was associated with yoke wear as a root cause, you would have a good point.
If differential bearing or gear failure was a common problem and was associated with yoke wear as a root cause, you would have a good point.
Last edited by 63mako; Jan 27, 2012 at 02:46 PM.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
You (and others) talk a great theoretical game, but that's about it.
Melting Slicks
Joined: Apr 2000
Posts: 3,341
Likes: 6
Ok.
Pro
Joined: May 2011
Posts: 581
Likes: 5
From: BC
To keep things in prospective one should know what different people's definition of "safe" is.
Mike Ward has previously led us to believe that as long as the wheel isn't leaving the car, it's safe. In a previous thread on the subject when discussing the disadvantages of camber change due to worn yokes Mike told us that he also sees no problem with loose bushings in the lower strut.
I'll go on record as saying that I believe that looseness in the attaching points of the suspension qualifies as unsafe, regardless of whether the wheel will fall off or not.
I think .050 is plenty of wear. If I had that and the diff was still in the car, I likely wouldn't do anything with it. However, if I had the diff out for any reason and had that play I would correct it and bring it down to near .000. You wouldn't tolerate .050 lateral play in an upper ball joint why would it be okay in the upper control arm of the rear? If you're a performance enthusiast and looking the squeeze the most out of your car's handling, this would be a no brainer. Not much point in tweaking the geometry and going to any kind of high performance components anywhere and leave slop in the rear wheel like that.
Steve g
Mike Ward has previously led us to believe that as long as the wheel isn't leaving the car, it's safe. In a previous thread on the subject when discussing the disadvantages of camber change due to worn yokes Mike told us that he also sees no problem with loose bushings in the lower strut.
I'll go on record as saying that I believe that looseness in the attaching points of the suspension qualifies as unsafe, regardless of whether the wheel will fall off or not.
I think .050 is plenty of wear. If I had that and the diff was still in the car, I likely wouldn't do anything with it. However, if I had the diff out for any reason and had that play I would correct it and bring it down to near .000. You wouldn't tolerate .050 lateral play in an upper ball joint why would it be okay in the upper control arm of the rear? If you're a performance enthusiast and looking the squeeze the most out of your car's handling, this would be a no brainer. Not much point in tweaking the geometry and going to any kind of high performance components anywhere and leave slop in the rear wheel like that.
Steve g
Drifting
Joined: Jul 2002
Posts: 1,995
Likes: 110
From: Garland Texas
resdoggie, Next time I get up there I'll be glad to stop by. But for now I'll be happy with pictures. Jack up the vette with the rear wheels hanging and take a few pictures where the stub axles goes into the diff.
I will do the same showing pictures of bearing races with metal shavings imbedded in them and trash in the pinion bearing cavity.
Mike
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Reread post 12 about no metal in the bottom of the case.
resdoggie, Next time I get up there I'll be glad to stop by. But for now I'll be happy with pictures. Jack up the vette with the rear wheels hanging and take a few pictures where the stub axles goes into the diff.
I will do the same showing pictures of bearing races with metal shavings imbedded in them and trash in the pinion bearing cavity.
Mike
resdoggie, Next time I get up there I'll be glad to stop by. But for now I'll be happy with pictures. Jack up the vette with the rear wheels hanging and take a few pictures where the stub axles goes into the diff.
I will do the same showing pictures of bearing races with metal shavings imbedded in them and trash in the pinion bearing cavity.
Mike
Last edited by resdoggie; Jan 28, 2012 at 08:34 AM.
Melting Slicks
Joined: Sep 2010
Posts: 2,413
Likes: 59
From: Emerald Isle NC
My diff with 100,000 mi. had 1/4" and 3/16" of endplay. Yokes worn down to c-clips, metal in fluid. Can't see where that's any good at all.
GTR1999 agreed.
New yokes installed.
Drive on them at your own risk.
GTR1999 agreed.
New yokes installed.
Drive on them at your own risk.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
OK, can't leave it alone. Failed differentials are very common in these cars. See how many C3 differentials are still good, not in need of rebuild and untouched @ 100,000 miles. Then compare the differential longevity in other vehicles. My 72 differential with 112,000 was trashed to the point the case couldn't be saved yet the original trans and engine were in perfect working order and the only oil leak was a valve cover gasket. Many of the 78 -79 differentials need a complete rebuild @ 50,000. These differentials have failed prematurely due to contaminated oil and worn yokes and, yes it is rampant and across the board. Many vehicles can run 200,000- 300,000 with the stock differential untouched. Not C3's. Luckily I was able to find a correct date coded differential that was rebuildable for $400.
Last edited by 63mako; Jan 27, 2012 at 02:48 PM.