Hi all, have a 4:11 differential that was just rebuilt. Noticed little to no end play in side yokes. Measured one at .004 and the other has no play meaning could not even get the .0015 feeler gauge to fit between the end of the shaft and the center pin. Is this a problem? There was no issue installing the yokes at all and snap rings are fully engaged. Just want to get this right before I put the cover on and fill it. Thank you for your time.
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Re: C2 differential side yoke end play
Joey
I set all my diff axles at 005-007" endplay. Yours are too tight. Were rebuilt axles used and how was the posi built? makes no difference if it is a 3 or 4 series posi case, the only difference in them is the flange thickness.
Questions regarding axle end play usually are the opposite of your issue, I have seen " rebuilt" diff's with axle endplay of 020-030-040" or more. All of those are terrible for a rebuilt differential and more in line with a worn or sloppy set up one.
Is there endplay in the side gears? Not lash but actual in/out play in the gear? Are the 4 springs installed or is this a tuned posi, without springs?
Did you rebuid it or had it rebuilt? if you had someone do the work did you contact them? -
Re: C2 differential side yoke end play
Hi Gary,
I purchased from ...... and plan to call them tomorrow. The axles were restored originals, springs are in but I can't answer the other questions you have but bottom line my thinking was too tight and you confirmed that. What would happen if I didn't address this issue?Last edited by Joey P.; December 10, 2018, 06:42 AM.Comment
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Re: C2 differential side yoke end play
Joey
I would like to know what "restored" originals means? Rebuilt axles are faced to the snap ring groove and new hardened tips pressed on. With original 63 to about 72 axles they were hardened and most have little wear on them. I clean them up, paint, polish in my lathe, and install new shields. With the rebuilt axles the dimension from the face to snap ring is all over the place but usually undersize leading to excessive endplay. Usually with tight endplay the snap ring doesn't install easily. If you removed the axles the originals have small center hole in them, rebuilts are smooth faced. New axles have the holes but some of them are not hardened.
The axle will always hit the cross shaft in the case. Without a small gap of 005 to say even 010" the axle will ride all the time against the shaft, if not hardened they will wear out.
Since you have the cover off I would swap out those old hex head bolts for socket heads and check to make sure there are no cracks in the posi case. Look close, if that is an original posi case it would be the type with the 1" square window, used from 65-68 and NOT too good due to being very prone to cracking. If there is a " tear-drop" window case there then it is not the original one to the carrier- if that is important. The tear drop cases are better.
If you would like me to look over the diff for you, send me several close up pictures. I am not saying your vendor did anything wrong but I have seen a lot of diff's from these cars and some "rebuilts" over the years needed attention.Comment
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Re: C2 differential side yoke end play
Thanks Gary, I took more photos this morning. Appreciate you taking the time to review them.Last edited by Joey P.; December 10, 2018, 06:34 AM.Comment
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Re: C2 differential side yoke end play
The overhaul manuals have no specification for axle end play. They only spec differential gear backlash (don't confuse this with ring and pinion backlash), and I recall it's one to six thou.
The Chevrolet Power manuals DO recommend an axle yoke end play and I believe it's zero to five thou, so you may be okay as long as you could get the snap ring in without forcing it.
During breakin, there will probably be enough clutch wear to increase axle end play by a thou or so.
GMPD used to sell Positraction shims. They were installed between the case and last clutch disk, so once the diff was assembled and had the proper differential gear backlash and was installed in the carrier, you could adjust yoke end play to whatever you want, but it requires removing the diff. and disassembling it to replace the shims.
Back in the seventies I bought a new complete Positraction differential case from GM. Diff. gear backlash was in spec and after installing it into the carrier with the proper shim preload I measured yoke end play of five and seven thou. I thought about disassembling everything to reshim the case, but decided that since the car would likely have light service from that point on, it was okay.
DukeComment
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Re: C2 differential side yoke end play
Joey
I will PM you my contact info to review off line.Comment
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Re: C2 differential side yoke end play
Here are the pics, thanks for reviewing.Comment
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Re: C2 differential side yoke end play
Chamfer is in place on both. I don't see any rollback burrs on the spline slots. If they are in the 50-55 Rc range and one is slightly tight a kiss cut on a surface grinder will dial them in.Comment
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Re: C2 differential side yoke end play
Ok, thanks Gary. So do you think the axles are original given the center drill or due to length are they not?Comment
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Re: C2 differential side yoke end play
Those appear to be original, rebuilt don't have the holes. New aftermarket do but those are used axles. Ck the hardness and go from there. If soft they are from a C3 most likely but that doesn't matterComment
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