Diff side yoke specs

69427

69427

The Artist formerly known as Turbo84
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Clinging to my guns and religion in KCMO.
I've got a touch too much end play on the right side of my spare 3.08 rear end (currently residing in my new frame). I'm planning on pulling it apart in the near future. I've got a few spare "HD" yokes (used) laying around, and I'm considering putting them in while I've got the rear end open. Can someone tell me what the nominal specs are for side play and yoke end "length" (distance between the snap ring groove and the shaft flat end).

Thanks,
Mike
 
PDC is about 1/16 inch...but acording to Gary and Mike i'ts much closer for total performance use....

I have seen them at 1/8 inch...but think anything over that is totally off the map dangerous....

wear on the yoke ends and the snap/retaining ring is toast...

much less wheel alignment/stability problems...

:shocking::gurney:
 
mrvette said:
PDC is about 1/16 inch...but acording to Gary and Mike i'ts much closer for total performance use....

I have seen them at 1/8 inch...but think anything over that is totally off the map dangerous....
wear on the yoke ends and the snap/retaining ring is toast...

much less wheel alignment/stability problems...

:shocking::gurney:
Click to expand...

I agree Gene and get this; I had my differential rebuilt by VanSteel and the yoke end play was well over .125 out their door. This was measured with a feeler gauge. I pointed it out and all Art could say is that's the best you can get them sometimes. Fool me the first time, shame on you. There are plenty of places where .125 play is routine and unknowing folks pay with a smile. As for me, you won't get me a second time. On the next rebuild, I will have the tolerances I expect signed and guaranteed by the re-builder.
 
Mike what year is it? I'm assuming it's an iron diff(63-79).

Check the distance from the yoke snap ring to the face- should be .180-.187 if under they're crap. This is true for used, rebuilt and new.The majority of play is in the posi. I set my work to 005-010"

Red,
EVERY posi I polish & tune I have to grind to fit the yokes for endplay, to say .125" is the best is,... well, you can fill in the blanks. I have recieved in rebuilt yokes that were bad and I rejected them, I have never ended up with more then 010 endplay. I would check your unit out sounds like a lot of play in there, could have other issues.
 
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GTR1999 said:
Mike what year is it? I'm assuming it's an iron diff(63-79).

Check the distance from the yoke snap ring to the face- should be .180-.187 if under they're crap. This is true for used, rebuilt and new.The majority of play is in the posi. I set my work to 005-010"

Red,
EVERY posi I polish & tune I have to grind to fit the yokes for endplay, to say .125" is the best is,... well, you can fill in the blanks. I have recieved in rebuilt yokes that were bad and I rejected them, I have never ended up with more then 010 endplay. I would check your unit out,sounds like a lousy job.
Click to expand...

YOU ain't kidding, I do about 20% of the work YOU do for a rebuild on them things....but at least I manage to get some end play tolerance fairly snug....

less than 1/16 anyway....with fresh enough/new yokes the mear though of one of them snapping outta there with me flipping it around, means my 'flip' becomes more REAL, and being a rag top, that is somewhat EARitating....

:crap:
 
GTR1999 said:
Mike what year is it? I'm assuming it's an iron diff(63-79). It's a C3 iron unit. I don't recall what year. I'll be pulling it out soon, so I'll have more info later.Check the distance from the yoke snap ring to the face- should be .180-.187 if under they're crap. This is true for used, rebuilt and new.The majority of play is in the posi. I set my work to 005-010" Is .180" the recommended minimum, or the factory manufacturing spec minimum? I'm just trying to understand how to interpret the amount of wear that may or may not have occurred with the present yokes and the HD replacement yokes.
Red,
EVERY posi I polish & tune I have to grind to fit the yokes for endplay, to say .125" is the best is,... well, you can fill in the blanks. I sure would not accept it nor would I have paid for it.
Click to expand...

I appreciate your input, Gary. I expect I might have a few more questions once I get the rear end apart.
 
69427 said:
GTR1999 said:
Mike what year is it? I'm assuming it's an iron diff(63-79). It's a C3 iron unit. I don't recall what year. I'll be pulling it out soon, so I'll have more info later.Check the distance from the yoke snap ring to the face- should be .180-.187 if under they're crap. This is true for used, rebuilt and new.The majority of play is in the posi. I set my work to 005-010" Is .180" the recommended minimum, or the factory manufacturing spec minimum? I'm just trying to understand how to interpret the amount of wear that may or may not have occurred with the present yokes and the HD replacement yokes.
Red,
EVERY posi I polish & tune I have to grind to fit the yokes for endplay, to say .125" is the best is,... well, you can fill in the blanks. I sure would not accept it nor would I have paid for it.
Click to expand...

I appreciate your input, Gary. I expect I might have a few more questions once I get the rear end apart.
Click to expand...

In '80 in had a Doc take my rear end apart, when done, he said parts of me were now perfect....been showing them ever since....:crap::crutches::D
 
Gene you're a sick man:lol:

Mike, .180 is about the minimum I would use. This is the dimension from the face to the snap ring, I don't know what the GM spec was on them, I never saw a print. I do know that if the posi is setup stock and sloppy, like just about all the rebuilders do, the endplay will be all over the place. It will work and I'd guess very few would even know to check them once they get them back, Red did and found some poor work.Good example of the type of work out there these days from more then one place.

I had a well known vendor(not Lonestar) ship me some new yokes last year to use. They were imported and cost less then the rebuilt GM's. Well I checked them and the only dimension I took for granted was the snap ring groove- guess what they were all over the place. I guess they copied worn out yokes because they were in the .150 range. Endplay was in the 030 range and I rejected it. Sent them all back.:crap: Installed Lonestars yoke, ground to fit at 007"
 
Thanks for the info, Gary. Looks like my (HD) yokes have plenty of meat left on them, so I'll transplant them into the diff when I get it apart. I was scrounging through my supply of differential parts, and it looks like I've got most of the parts I'll need. As I mentioned earlier, I expect to be requesting a bit of advice down the road, and direction for locating parts that I might require once I get it open.
For now, is there a source for the u-joint/yoke caps that you think are decent pieces?

Thanks again,
Mike
 
The GM yoke caps run between $20 -$40 each on ebay. The aftermarket ones that I've seen are crap. The ones Mike can get may be the way to go.
I think the importance of these "HD" yokes has been over stated. They are the exact yoke as the std, the only difference is in the joint retention. The cap and bolts are good but I think the u-bolts are fine for a driver. When I blew apart that U-joint it was the outer joint and not the inner.

Be sure to use good parts, there are few kits out there and some are cheap junk with the same price as the quality sets. Use National or CR(SKF) seals only, Timken USA bearings, solid steels,ARP RG bolts,etc. If you need parts I have the same I use here.
 
Belgian1979vette said:
If you have a business Gary you should get yourself a creditcard payment method, so foreigners can order with you also.

Yves
Click to expand...

I have helped others occationally with that sort of stuff, glad to help if I can....a PP account gets me the money, I deal for the parts here on this side, and send them in a USPS box/envelope.....easier customs that was I UNDERSTAND...YMMV....

:crutches:
 
Belgian1979vette said:
If you have a business Gary you should get yourself a creditcard payment method, so foreigners can order with you also.

Yves
Click to expand...

Yves
I don't really have a business per say,I'm more of a hobbyest. I can get parts to people anywhere as long as the weight is not an issue. Shipping a diff out of the USA is possible, just expensive. Of course it's no more then anyone else can ship them for either. The small stuff can go USPS overseas and gets there pretty fast. Paypal works as well they just tack on 4%.
 
GTR1999 said:
The GM yoke caps run between $20 -$40 each on ebay. The aftermarket ones that I've seen are crap. The ones Mike can get may be the way to go.
I think the importance of these "HD" yokes has been over stated. They are the exact yoke as the std, the only difference is in the joint retention. The cap and bolts are good but I think the u-bolts are fine for a driver. When I blew apart that U-joint it was the outer joint and not the inner.

Be sure to use good parts, there are few kits out there and some are cheap junk with the same price as the quality sets. Use National or CR(SKF) seals only, Timken USA bearings, solid steels,ARP RG bolts,etc. If you need parts I have the same I use here.
Click to expand...

Thanks for the additional info, Gary. I appreciate it.
I checked ebay after reading your post. Yeah, that's a bit more than I want to spend for four little caps right now. I've got some on the original differential, but it (along with a bunch of my other "not needed" parts) is stored out of state at my in-laws. Instead of buying new caps, I think I'll just pay the postage and have my FIL mail them down to me.
I agree the HD cap setup isn't terribly stronger than the standard type, but it's a freebie "upgrade", as I've already got the parts sitting around. (I only do road course stuff, and I've had no problems with other rear ends with the U-bolt setup.)
I got most everything disconnected from the differential this afternoon. Just the two batwing bolts and the pinion bracket bolt left to remove, and it'll be out.
A question: I think I have some factory PN yoke snap rings, but just in case, are they an odd width or anything?
 
I use the snap rings from Lone star, they're pretty good. Some I've seen are thinner and flex more then I like. My local bearing supplier couldn't source the original ring size either.
 
Crap, While I'm at it........

Gary,
I pulled out the side yokes and measured the shaft end lengths. They were in the one fifties, well below one eighty as you mentioned. It was visually obvious that there was wear on the ends. I also measured the cross shaft, and it was within a couple thousandths. It's obvious which parts do the wearing. The "new for me" HD yokes are in the one eighties, so I'll be using them. While I was playing around measuring things, I decided to shim up the clutch plates to get rid of some of the diff gear backlash, so I took the thing apart. It's been twenty years since I last had it apart, and outside of the yokes, things looked okay.

IM001134.jpg

I had the differential apart several times swapping shims to reduce the backlash. Got a couple questions. What is a ballpark torque number to rotate the differential without the springs (so I don't have to keep removing and installing the springs while I'm shimming things)? (Another reason for doing the tests without the springs is one of them went flying across the garage earlier :crap:, and I haven't found the damn thing yet.) I'm trying to reduce the backlash, but not get into a situation, if possible, where a couple "high" teeth bind up the differential.
I enjoy most aspects of working on the Corvette, but I never have liked the smell of antifreeze or ninety weight.
Thanks again.

PS: I noticed that the yoke snap ring ends (where the pliers hook to) look like they can contact the posi spring bracket when the differential action is ocurring. Am I correct or imagining things?
 
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I would not go crazy looking for that spring. I store the springs and plates in the outside dumpster.

Read my posi tuning thread and rebuilding thread, it will save me from typing it all out again.

I found high spots in new spiders that I had to dress. Polish the case while you have it apart as well. If you have the snowflakes then replace them with solids.
Use socket heads in place of the hex head cap bolts and check the caps for rock. You want 001-0015.
 
Gary,
I read your posts about rebuilding the differential. Very interesting reading. Thanks for taking the time to post all that.
Well, given that I haven't found that spring yet, and just the plain curiosity of how well the posi would work without it, I'm leaning toward just leaving the springs out. (If anybody asks, I'll just say it was part of my weight reduction list. ;))
As I mentioned earlier, I'm curious what sort of rotational torque numbers I should see without the springs. I've got a setup nearly finished to rotate the yokes with my beam torque wrench.
I've done a quick test fit of the yokes/snap rings. Without any spring pressure/compression on the clutches, it looks like I've got darn near zero yoke endplay. I'd sure like to not have to take any material off the end of the yokes.
Just for amusement, I'm going to drop by a welder/machinist friend's shop back home (he did the aluminum welding on my narrowed batwing and my bearing carrier/caliper brackets) with the old yokes, and get his opinion about welding and machining a new end on these. I don't figure I have much to lose talking to him or trying it.
I was proofreading this, and a question popped into my head. This whole "wearing out and throwing away the yoke" thing has always struck me as a bad design issue. Take the front or rear wheel bearings for example. If you wear out the bearings, you don't throw out the whole hub, as there's inexpensive replaceable races that you R&R. It would have been nice if there was a similar inexpensive option for the yokes. I'm curious, instead of grinding the ends of the yokes to get a touch of clearance, what is the downside of just taking a slight amount off the side of the cross shaft? Despite how much the yokes had worn in this rear end, the cross shaft only had about one or two thousandths of wear on it. It sure looks like it would still have sufficient meat to be able to do the job in the event of removing a couple thousandths (from just two narrow strips), instead of grinding the yoke ends for clearance. I have no idea what the hardening depth of that shaft is, but I assume it's similar to the yoke ends.
I'll sure be glad to get the rear end back together for two big reasons. I'm interested in finally driving the car, and I'm tired of inhaling ninety weight.:sick:
 
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