rear end
Race Director
Joined: May 2003
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From: California
The reason I noticed a c-clip was missing was the rear end of my 79 was squirrely on curvy roads here in WV. A missing c-clip definently makes a difference in handling on curses as the stub axle slips in and out of the differential. If you always drive on straight roads you will probably never notice the slop in your rear suspension.
happened to me also... Could also be bad bearing..
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
A missing C clip is usually a symptom of worn side yokes. If the side yokes are not worn the c clip will stay put. If the side yoke is worn enough to lose the c clip the diff fluid is full of metal shavings from the worn yoke. The lower strut rod is fixed. When the side yoke wears the top of the wheel will tilt in, the more wear the more tilt. This negatively affects handling and tire wear. You could ignore this and adjust the strut rods to align the wheel but you still have a bunch of shavings and a c clip or chunks of c clip flying around in the differential when driving. You can change the fluid but the metal shavings will settle to the bottom when parked so how do you get them all out? If there is a 1/4" of play there are problems that need to be addressed.
Pretty obvious to me. Drop the pumpkin and fix it right. If you keep driving it like that and ignore it as some have suggested you can have the sideyoke start digging in to the differential case. Once this wears to much the case is junk and no longer rebuildable and the core value is shot on an exchange as well. "Don't worry about it, there are millions of corvettes with worn side yokes" is not a good answer.
Pretty obvious to me. Drop the pumpkin and fix it right. If you keep driving it like that and ignore it as some have suggested you can have the sideyoke start digging in to the differential case. Once this wears to much the case is junk and no longer rebuildable and the core value is shot on an exchange as well. "Don't worry about it, there are millions of corvettes with worn side yokes" is not a good answer.
Race Director
Joined: Jul 2001
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If you keep driving it like that and ignore it as some have suggested you can have the sideyoke start digging in to the differential case. Once this wears to much the case is junk and no longer rebuildable and the core value is shot on an exchange as well. "Don't worry about it, there are millions of corvettes with worn side yokes" is not a good answer.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
A missing C clip is usually a symptom of worn side yokes. If the side yokes are not worn the c clip will stay put. If the side yoke is worn enough to lose the c clip the diff fluid is full of metal shavings from the worn yoke. The lower strut rod is fixed. When the side yoke wears the top of the wheel will tilt in, the more wear the more tilt. This negatively affects handling and tire wear. You could ignore this and adjust the strut rods to align the wheel but you still have a bunch of shavings and a c clip or chunks of c clip flying around in the differential when driving. You can change the fluid but the metal shavings will settle to the bottom when parked so how do you get them all out? If there is a 1/4" of play there are problems that need to be addressed. Pretty obvious to me. Drop the pumpkin and fix it right. If you keep driving it like that and ignore it as some have suggested you can have the sideyoke start digging in to the differential case. Once this wears to much the case is junk and no longer rebuildable and the core value is shot on an exchange as well. "Don't worry about it, there are millions of corvettes with worn side yokes" is not a good answer.
Pretty obvious to me. Drop the pumpkin and fix it right. If you keep driving it like that and ignore it as some have suggested you can have the sideyoke start digging in to the differential case. Once this wears to much the case is junk and no longer rebuildable and the core value is shot on an exchange as well. "Don't worry about it, there are millions of corvettes with worn side yokes" is not a good answer.63mako nailed it
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
That would be you. (see bold quote below)
This is your response to a guy who started a thread that had over 1/2" of end play in his side yoke and screaching metal noises on turns.
Here is the thread. I thought the highlighted quote from you was **** poor advice then and I still think the same way. "Do what you like with it."http://forums.corvetteforum.com/c3-t...hat-to-do.html
My response to your post then is post # 13 on that same thread. I think addressing the issue earlier rather than later can save the housing and wear on the ring and pinion and spyders which is considerable expense.
I will offer a very different opinion, do what you like with it.
There's thousands if not tens of thousands of C2/C3 Corvettes running around for years with worn diffs just like yours. In most cases the owners have no idea that the side yokes have lost their circlips and the side yokes are 'loose'. You yourself were none the wiser until your car got inspected- nothing in the handling prompted you to start looking, just like the other thousands that are also 'in the dark'. I know of several owners who deliberately left the circlips off during the last rebuild. They report no negative effect on handling whatsoever.
If the engineering calculations are done properly, the only time a side yolk is completely unloaded is either when the car is off the ground or has slid sideways into a curb striking the lower part of the tire and wheel. While driving in a straight line there is approx. 300 lbs of force pushing the yoke inwards. While cornering this number changes by a only a minor degree, contrary to popular thinking. At no point does it reach zero or achieve a negative value.
The small circlips chosen by GM to retain the yokes are not a load bearing part of the rear suspension system. If they had been, something more substantial than a stamped steel circlip would have been used, and GM would have incorporated a method of controlling and adjusting yoke end play precisely, much as is done on the front and rear wheel bearings.
With all that in mind, I would continue driving the car as-is. I would also plan to eventually overhaul the entire diff and not just swap the yokes. Once the unit is opened up, you are likely to find many components that need attention up to and including the ring and pinion gears. Consider buying an exchange unit and returning yours as a core.
There's thousands if not tens of thousands of C2/C3 Corvettes running around for years with worn diffs just like yours. In most cases the owners have no idea that the side yokes have lost their circlips and the side yokes are 'loose'. You yourself were none the wiser until your car got inspected- nothing in the handling prompted you to start looking, just like the other thousands that are also 'in the dark'. I know of several owners who deliberately left the circlips off during the last rebuild. They report no negative effect on handling whatsoever.
If the engineering calculations are done properly, the only time a side yolk is completely unloaded is either when the car is off the ground or has slid sideways into a curb striking the lower part of the tire and wheel. While driving in a straight line there is approx. 300 lbs of force pushing the yoke inwards. While cornering this number changes by a only a minor degree, contrary to popular thinking. At no point does it reach zero or achieve a negative value.
The small circlips chosen by GM to retain the yokes are not a load bearing part of the rear suspension system. If they had been, something more substantial than a stamped steel circlip would have been used, and GM would have incorporated a method of controlling and adjusting yoke end play precisely, much as is done on the front and rear wheel bearings.
With all that in mind, I would continue driving the car as-is. I would also plan to eventually overhaul the entire diff and not just swap the yokes. Once the unit is opened up, you are likely to find many components that need attention up to and including the ring and pinion gears. Consider buying an exchange unit and returning yours as a core.
Last edited by 63mako; Mar 27, 2010 at 02:11 PM.
Race Director
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The OP had. 015" play as it turns out, not half an inch. Read further on. I knew that at the time, the rest of CF didn't.
The discussion was 'is the car dangerous' not 'does my diff need an overhaul'. I answered in context.
The discussion was 'is the car dangerous' not 'does my diff need an overhaul'. I answered in context.
Race Director
Joined: Jul 2001
Posts: 15,892
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Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
What is your advice to this threads poster who has .250 endplay? Mine is to pull the pumpkin and rebuild it before more damage happens.
Race Director
Joined: Jul 2001
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Must have ESP. OP posted this .015 measurement 11 days after your answer and had obtained that measurement a couple of days previous to the measurement post..
What is your advice to this threads poster who has .250 endplay? Mine is to pull the pumpkin and rebuild it before more damage happens.
What is your advice to this threads poster who has .250 endplay? Mine is to pull the pumpkin and rebuild it before more damage happens.
I will state my position to make it clear.
- End play of any amount is not a safety or driveability issue.
- End play of .250 is a durability and cost issue only.
Once a yoke is scrap, it's scrap. I don't believe that a diff with .125 play on the yokes is cheaper to overhaul than a similar diff but with .250 play. Once the dust shield on the yoke digs into the housing it gets expensive.
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
There were several PM's between that OP and myself as well as on other issues where he could not get a straight answer.
I will state my position to make it clear.
- End play of any amount is not a safety or driveability issue.
- End play of .250 is a durability and cost issue only.
Once a yoke is scrap, it's scrap. I don't believe that a diff with .125 play on the yokes is cheaper to overhaul than a similar diff but with .250 play. Once the dust shield on the yoke digs into the housing it gets expensive.
I will state my position to make it clear.
- End play of any amount is not a safety or driveability issue.
- End play of .250 is a durability and cost issue only.
Once a yoke is scrap, it's scrap. I don't believe that a diff with .125 play on the yokes is cheaper to overhaul than a similar diff but with .250 play. Once the dust shield on the yoke digs into the housing it gets expensive.
One thing I would recommend you check, with the amount of endplay you report,is to see if the yokes are hitting the housing. This is important to check because if left with slop the yoke will grind the 1/8 boss off the housing and start on the seal, then you may loose the whole deal. No one will give you a dime for it as a core either.
Your problem is a very common one with these cars. How it is corrected,if it is,depends on the mechanic/owner. With that much wear in the yokes chances are the bearings gears and posi case need attention. It can add up real fast,from a basic $600 master kit job to Thousands for a 1000 hp deal.
My 69 yokes were so bad years ago, I felt the rear end sway in curves at 65 mph on the highway.
Your problem is a very common one with these cars. How it is corrected,if it is,depends on the mechanic/owner. With that much wear in the yokes chances are the bearings gears and posi case need attention. It can add up real fast,from a basic $600 master kit job to Thousands for a 1000 hp deal.
My 69 yokes were so bad years ago, I felt the rear end sway in curves at 65 mph on the highway.
1. With 1/4 inch of endplay I bet the yoke is digging into the case. My fresh rear end does not have a 1/4" gap between the shield and housing. Haven't seen any that do.
2. Gary states above excessive yoke wear leads to cumulative damage to many other internal components listed above increasing the cost of rebuild.
3. Excessive yoke wear causes the rear end to sway in curves at 65 MPH on the highway. This is a safety and drivability issue.
Got to throw up the
flag again.
Race Director
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From: California
I can attest to this, my first rear end build, out of 4 now, came along because i put it in the alignment shop, because it felt like a boat when going around big curves fast, it was a bad yoke..... fixed rear rend ... problem went away....
Le Mans Master
Joined: Jan 2006
Posts: 6,505
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From: Butler Pa
You're all assuming that the OP's yokes are worn out. That's not necessarily true. If the clips are actually missing, you can jack the car up and easily move the yokes 1/4", even if they were brand new. And IME it won't cause any problems.
Melting Slicks
Joined: Dec 2009
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From: Thunder Bay
Its highly unlikely the clips would have fallen out if the yokes weren't worn out.
Racer
Joined: Dec 2004
Posts: 410
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From: Wichita Kansas
I had a broken clip, replaced it and Autox'd the car for alot of years and never broke another clip, (although for the last few years I shim them between the clip and spider gear). Matter of fact I just replaced that yoke, as it failed in the spline. I also meant the camber on the inside rear tire in a turn can go positive in an earlier part of this thread.
Le Mans Master
Joined: Jan 2006
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From: Butler Pa
Team Owner
Joined: Mar 2002
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The reason I noticed a c-clip was missing was the rear end of my 79 was squirrely on curvy roads here in WV. A missing c-clip definently makes a difference in handling on curses as the stub axle slips in and out of the differential. If you always drive on straight roads you will probably never notice the slop in your rear suspension.
No ... no it didn't.
It's amazing how many of you believe that flimsy little unmachined circlip with a gap in it is intended to support the cornerning loads of a 3500 lbs car.
It doesn't.
The only time that stub axle is outwardly loaded is if the wheel is off the ground or if you've slid into a curb. Under any and all other conditions, the axle is loaded inward.