Hello all.  Back in August I replaced my differential yokes and snap-rings (old one on the drivers side was shorn off and yoke was hanging out).  After completing the job I had an alignment done and the within 15 miles it died.  The driveshaft spins but not the tires – work heated up so the car has sat until now. Saturday I am opening up the differential case to see what the deal is.  My driveshaft is over to the passenger side, I read that most C3’s are like this – but I thought I would mention it since perhaps its an alignment issue putting undue stress on the driverside yoke and that’s busting the snap ring.

 

At this point I think I am going to remove the rear and have it rebuilt – if I do can I install the rebuilt rear myself or is there a technical alignment that really needs a professional?  I mean, aside from the 4 wheel which I would need afterwards.  I was looking at parts online and assuming $200 in labor a rebuild could run me about $700.  Alternatively, Ecklers sells a rebuild for $1,000 – I am not concerned for the cost difference.  I am more concerned if I can treat a rebuild like plug and play plus a wheel alignment and be ok ?

 

Any thoughts? 

Crimson Ghost2010-11-05 03:50:56

The diff is mounted solidly to the rear crossmember...ain't really but one way for it to go, so there's no alignment issues with the remove/install.
And yes...all Corvettes(and most other cars too) have the engine/trans off-set to the passenger side slightly. This has more to do with the clearance needed for the steering gear than anything.
Is the diff making any noise since it won't move? Was it making any noise before? The only things in the diff that would keep the car from moving would definitely make noise if broken/failed. If it is a posi unit, you could have one of the yokes stripped, but it should still move the car, unless the posi clutches were wiped out.
This is a strange one...
Go ahead and save the $$$ on the labor to remove/install the diff, and do that yourself. There's really nothing you could mess up by doing it yourself, except maybe leave a bolt out or something. There is no alignment issues with it. It simply bolts solidly to the crossmember, and then you have the front "nose" mount that attaches the diff thru a cushion to the frame.


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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Hello Joel, thank you for the response – I really appreciate it.  You confirmed my suspicion, when I replaced the yokes it certainly appeared to be a bolt on.

 

My yokes had too much play in them, after I installed the snap rings I could pull them out about a ¼ inch.  I have since read that the allowance is something like .0005 I was way over this.  I suspect this is the issue.

 

There was a clunk (a few actually) and I could tell something was wrong, but I tried to get home – no luck there.  It just died, no more go – yet no noise.  I jacked it up and ran it, the driveshaft spins, the passenger tire spins in the air and the driver side tire just sits there.  But there is no noise at all?  So I am at a loss.  

Sounds like the clutch pack has fried as well as the gear the yoke splines to on the inside of the diff..if you have posi..I would take it out and see what actually is broken..I have seen these rebuilt rears in Ecklers and Mid America..you can choose the gear ratio and posi..send in the old and get a rebuilt in the mail..only thing to think about is if the rear has a VIN or other number on it that says it came with the car..if you want to keep it original then have the one in the car rebuilt locally..or send it to Joel! I am sure he has done plenty of them..
Rich

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My first parade at Carlisle 2010

The real question is why did it happen.  

 

The yoke was hanging out on the drivers side about 2 inches when the car was lifted.  So I opened it up, replaced both yokes and snap rings.  Put it back together and drove it a few miles – had a 4 wheel alignment done and it clunked right after the alignment and was broken within a few miles.

 

I am fearful that there is something else causing the issue.  I don’t want to spend $1,000 and have it break again – this is why I asked about alignment.  Right now I understand that the differential assembly can only be installed one way and no alignment is done out side of the case.  I am going to remove it today and have it rebuilt locally – will probably order the parts from Ecklers and then just have the labor to contend with.  I am certain I will be back to ask you all what I need to order.  I think this is a 3:70, later today I will count teeth and then get back to you all.

 

I started another thread asking for advice on removing this – I was uncertain how to go about the strut’s.

If it didn't make any noise on the way to get a 4WA then maybe I mean maybe when they adjusted for camber it moved the top of the wheel out which would pull the axle out a little and make a weak part in the rear stress and fail faster than what it would have..it would have failed regardless as you said endplay was over a 1/4 of an inch.
Rich

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My first parade at Carlisle 2010

[QUOTE=yostusota]If it didn't make any noise on the way to get a 4WA then maybe I mean maybe when they adjusted for camber it moved the top of the wheel out which would pull the axle out a little and make a weak part in the rear stress and fail faster than what it would have..it would have failed regardless as you said endplay was over a 1/4 of an inch.
Rich [/QUOTE]

Any opinion on this:

Oh well no big deal..I guess the causal part of failure was the diff..I would say that anything drive train related should have very little end play..check your rear wheel bearings also..you really shouldn't feel them move and need a dial indicator to see how good they are..if they are good get the packing tool from Mid America..I don't know if Ecklers has it..since you have the shafts out it only takes a few minutes to grease them..
Rich

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My first parade at Carlisle 2010

Oh, I am new to everything - I bought this car to learn on.  I don't know how to check the wheel bearings :-)

on the EBay rebuild it looks to have everything on it..I noticed the ring gear had surface rust on it which makes me think they may not be new..they come with a oil coating on them that prevents rust..unless it was cleaned off..only worry buying it would be who rebuilt it..the guy selling it or someone else..if you are the second owner since the rebuild the warranty it has probably won't transfer to you..price is highly negotiable if he bought it for his car and now doesn't need it.
Rich

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My first parade at Carlisle 2010

Thanks Rich.  I emailed him and he said his reserve was set at $600 -- which is dirt cheap for what he has there.  But I have not yet removed mine to determine what I currently have - I am hoping I am a 3:70 but I suspect I might have a 3:08.  This guy has this one set up as a 3:90 - this might be too much with my comp cam I have (comp cam's thumpr).  My top end might be about 60 !  haha

Sorry it took so long to get back I was driving to my moms to hit Chip Millers show in West Chester PA..that diff is really cheap..I don't know what year you have but I have a 3:70 ratio and it tops around 145..65 in 4th is 3k rpm..235/65/15 tires..it depends how you drive it..I get awefull mileage though..I would be tempted to get that rear anyhow..can always swap the ring and pinion out of yours into it.
Rich

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My first parade at Carlisle 2010

I removed the differential assembly, drained it and opened it up.  The drivers side yoke has broken in half right where the gears start.  The snap ring is still in place, so that’s why it didn’t make any noise – I was spinning the tire and the yoke was spinning before it connected with the gears.  I don’t know why the other tire wouldn’t spin though?  It’s yoke appears good – I don’t know how to tell if the clutches are gone.

 

So what would cause the yoke to sheer in half like that?  

 

Also, I marked the good yoke and the drive shaft yoke.  I turned the drive shaft yoke about 3.75 turns  for the half shaft yoke to turn once.  Does that sound like I have a 3:70 ?

 

I was going to count gears, but all I can count is that large gear, the rest spins with it so I am not sure what other gear to count to do them math. 

 

I can’t imagine play on the yoke moving in and out would cause it to snap in half.  But I did hear several clunks from the rear within a couple miles of the failure.  So I am at a loss right now, what would cause the clunks and then the yoke to snap in half?  

Look on the outer edge of the ring gear, and you'll see two numbers. One is the pinion gear tooth count, and the other is the ring gear tooth count. Divide the larger number b y the smaller number, and you get the ratio....for instance, if you see 10  41, then you have a 4:10 ratio.
Or...you can simply look at the bottom of the diff housing, and get the diff code from there.

HEre's the thing about alignments, and that causing yoke failure. It's certainly possible, but I'd say very rare. Ya gotta take into consideration the design of this suspension. The halfshaft IS the upper control arm/link...anytime the car is on the ground, the weight of the car is pushing the yoke into the diff. The only way you could get the alignment off far enough to pull the yoke out, or put undue stress on them, would be to bend the crap out of the lower strut rods, but then the car would be very un-drivable.
Of course, if you are cornering pretty hard, or at high speeds, the pressure on the yoke will be less, but still not enough to pull the yoke outward enough to create an issue.
My thoughts on that yoke failing as quickly as it did was it was prolly just a bad part to start with...that's just my opinion, as I haven't seen the yoke, nor did I see it before it was installed.

What year model car is this, anyway? I keep forgetting, and it's not listed on your profile...


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Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Give Jim Stevens a call, he is a suspension specialists. His prices are resonable and stands behind his work. Lots of C-3 members have had work done by him. His #608-365-0911, hope this helps and saves you some money! Tell him your from C-3VR!

Here's what was found on dis-assembly of the diff. The yoke on the far right is from the driver side, the one in the middle is a new one, and the one on the left is from the pass side...it was about to let go, too! The second pic shows how twisted it is. Apparently, the reconditioned yokes that had just been installed were not heat treated properly, and that's what caused the failure...

 Clarification: John was having trouble posting the pics, so he sent them to me, and I'm posting them for him.

  Adams' Apple2010-11-12 06:02:45

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Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Nice! Dare I ask where the broken parts came from? Glad to see Joel ended up with it. How's the rest look inside?
Rich

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My first parade at Carlisle 2010

I bought them from Eckler's.  Not sure if the blame for faulty parts can be placed with them, but I will say that I called them and they are taking them back with a 100% refund.

Glad to hear Ecklers is standing by their product..how is the vette shop? Not to far from my house but I haven't been there..is it nice?
Rich

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My first parade at Carlisle 2010

I’ll update you after my first transaction with them is complete.

 

I brought them the rear and they quoted me $500, then called me one day later they called and said the heavy duty yokes would be $150, bearings I can’t recall lets just say $150, clutch $170 – somewhere around $800and the $500 would be labor.  So I went from $500 to $1,300 and they wanted a credit card for a deposit at that point.  

 

Seemed like either bait and switch or an honest mistake – if its your business its difficult to think you could forget the price of the parts in your quote.  

 

So since I am on the subject – help me out here.  How many labor hours should I be charged for?  Clean out the rear (searching for old snap ring pieces), replace bearings, install yokes and new clutch (I asked for the clutch to be a little tighter than stock).  I asked for labor hours since I don’t know their hourly rate, but I plan to ask for it and I would like to know how many hours this job should be.  

Well I know how long it takes me but I haven't charged to do it either..I have no idea what the book time is..sounds like they have a flat fee to rebuild the rear..I get nervous when shops want a deposit to do work..I won't tell you what it cost me to do the last one I did but if the shop can't afford it they may have some serious cash problems..I am in NJ doing the work cert crap so I can't get to a labor book today..
Rich

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My first parade at Carlisle 2010

"Heavy Duty" yokes are usually the ones that require the straps and bolts, not the ones like you have, which use the u-bolt/nuts. They are a bit more expensive, tho. However, if you didn't request, or discuss them, why would they just automatically install them and charge you?
Labor time shouldn't be more than 3 hours, total. If they can't rebuild that diff in 3 hours, there's something wrong. As Rich says, they may just have a set price for that job, but $500 sounds a bit rich to me. Then again, if they do a good job, and it survives, it's prolly worth the peace of mind.

There are posi clutch spring kits that so add more pressure on the clutch packs...those things are a PITA to get in, too! Certainly hope they are replacing the clutches too, and not just adding the springs.



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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Darn Joel you let the cat out of the bag! Three hours would be a max deal in time..maybe a Friday night build with a few beers!
Rich

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My first parade at Carlisle 2010

Actually, the book shows 8 hours!! That includes almost 4 hours to r & r the diff. Also shows 30 minutes to replace the side(yoke) bearings! Dang....anyone using book time on this would make a killin!! Lemmie see here...2....6...carry the 4....that's $700 for this shop!! Woo Hoo! I'm goin tuh Didneyland!!! Adams' Apple2010-11-12 20:47:57

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Holy crap! I really should be getting something to do this..thanks Joel for letting me know I could have got a new clutch and exhaust with the ones I have done! Oh well I do it because I want to and really enjoy it.
Rich

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My first parade at Carlisle 2010

a quick update.  I picked up the rear after work this evening- I will send more pictures tomorrow. I installed the rear - I'll admit my stupidity too.....I connected the crossmember to the diff, put it on my floor jack and connected it.  Got the strut rods set and installed the new bushing.  Went to connect the halfshaft and noticed that I didn't adjust them to the front of the strut rod !  DOH !   so I have to remove the half shaft all together in order to pull it to the front and connect to the yokes :-)  

Good to hear, John!! Hope it survives a little longer this time!

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"