measuring differential yoke end play
Thread Starter
Racer
Joined: Dec 2011
Posts: 284
Likes: 4
From: Philadelphia Pennsylvania
measuring differential yoke end play
Because I already have everything apart I thought I'd check this as others had mentioned. I'm not sure how to measure it properly, though. Is this a measurement of the entire gap or just the movement of the yoke in&out of the differential? I'm just using different size allen wrenches to roughly measure the gap & movement. The amount of movement seems pretty small. Because my tools are imprecise the movement on the worst side is somewhere between .031 and .078.
What I mean is, with the yoke pushed in there's about 9.5/64" gap, with it pulled out there's about a 13/64" gap so maybe 3.5/64 (.054) actual movement
What I mean is, with the yoke pushed in there's about 9.5/64" gap, with it pulled out there's about a 13/64" gap so maybe 3.5/64 (.054) actual movement
Last edited by brianPA; Jul 16, 2012 at 11:16 PM.
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
0.078" is a bit more than I'd be comfortable with. Maybe not a reason by itself to pull the diff and rebuild, but if you're planning to refresh it anyway the play should be addressed. A fresh diff will be in the 0.005-0.015 range.
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
I would not be concerned with those measurements, I would not even think about it until it gets around .1, then it's something down the road. At .125 if there is some oppurtunity then consider pulling the diff. At .15 need to pull the diff.
When the yokes were new, there should have been .185 - .19 from the c-clip to the end. The end wears and there gradually becomes more of a gap. If the yoke is not replaced when required, then it can eventually wear to the point that the c-clip falls off.
When the yokes were new, there should have been .185 - .19 from the c-clip to the end. The end wears and there gradually becomes more of a gap. If the yoke is not replaced when required, then it can eventually wear to the point that the c-clip falls off.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
The yoke end wears, the center pin wears and the clutch pack wears. All contrbute to the play you see. .054 is not excessive. That said if everything else seems fine with no leaks and you haven't removed the differential, I would change the fluid and run it. If it is out and everything else seems fine pull the rear cover, c clip and pull the sideyoke and check the end for wear, if wear is noticable change it, clean out the case as good as possible and install fresh fluid once it is together. Replacing the yoke is a 10 minute job if the differential is on the bench. The replacement yokes are hardened better on the ends than the factory yokes especially the 78-79 yokes. They had issues from the manufacturer. I like the amsoil gear lube with no additve but others swear by conventional gear lube with posi additive.
Drifting
Joined: Jul 2008
Posts: 1,483
Likes: 459
From: Lititz PA
Originally, the rear in my '73 had about .12" end play on one side and about .18" on the other side. Van Steel rebuilt the rear and returned it with .008" on one side and .014" on the other. The rear in my car was leaking everywhere possible so it needed help. Plus, the half-shafts are the upper control arms for the suspension so I wanted to keep them in good shape.
John
John
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Thread Starter
Racer
Joined: Dec 2011
Posts: 284
Likes: 4
From: Philadelphia Pennsylvania
I have feeler gauges but they're way to thin to measure a 1/8" or greater gap. I know the yoke travel play is probably closer to .05 if I'm measuring it right, I just wanted to make sure it wasn't actually the ~.20 reading of total gap length (of which only ~.05 is movement)
I still have the differential in the car and I *really* don't want to take anything else apart at this point, I just wanted to sanity check it so if it was truly near destruction I could just bite the bullet now.
Leaving it in, thanks.
I still have the differential in the car and I *really* don't want to take anything else apart at this point, I just wanted to sanity check it so if it was truly near destruction I could just bite the bullet now.
Leaving it in, thanks.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
I have feeler gauges but they're way to thin to measure a 1/8" or greater gap. I know the yoke travel play is probably closer to .05 if I'm measuring it right, I just wanted to make sure it wasn't actually the ~.20 reading of total gap length (of which only ~.05 is movement)
I still have the differential in the car and I *really* don't want to take anything else apart at this point, I just wanted to sanity check it so if it was truly near destruction I could just bite the bullet now.
Leaving it in, thanks.
I still have the differential in the car and I *really* don't want to take anything else apart at this point, I just wanted to sanity check it so if it was truly near destruction I could just bite the bullet now.
Leaving it in, thanks.
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Eeh, you do know that you're supposed to stack feeler gauges together to measure greater distances, right?
I think several posters above missed that the bad side is almost 0.080". I agree that you don't have to take the diff out right away, but keep an eye on it. Once the yoke has worn through the surface hardening it goes fast.
You may also want to invest in a dial indicator and magnetic base. The hobby versions are quite inexpensive and good enough to measure this.
I think several posters above missed that the bad side is almost 0.080". I agree that you don't have to take the diff out right away, but keep an eye on it. Once the yoke has worn through the surface hardening it goes fast.
You may also want to invest in a dial indicator and magnetic base. The hobby versions are quite inexpensive and good enough to measure this.
Thread Starter
Racer
Joined: Dec 2011
Posts: 284
Likes: 4
From: Philadelphia Pennsylvania
Eeh, you do know that you're supposed to stack feeler gauges together to measure greater distances, right?
I think several posters above missed that the bad side is almost 0.080". I agree that you don't have to take the diff out right away, but keep an eye on it. Once the yoke has worn through the surface hardening it goes fast.
You may also want to invest in a dial indicator and magnetic base. The hobby versions are quite inexpensive and good enough to measure this.
I think several posters above missed that the bad side is almost 0.080". I agree that you don't have to take the diff out right away, but keep an eye on it. Once the yoke has worn through the surface hardening it goes fast.
You may also want to invest in a dial indicator and magnetic base. The hobby versions are quite inexpensive and good enough to measure this.
I had bought it when I was working on my motorcycle and never ended up taking out of the packaging.
I'll try to get a more accurate measurement and change the fluid.
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Mine were in the 0.125" range when I changed them. I drove it for several years like that with no major problem. If you have the diff out, change them. If not, do it next time the diff is out. And yes, keep an eye on them.
Drifting
Joined: Jul 2002
Posts: 1,995
Likes: 110
From: Garland Texas
Need more info about the diff in the car. I can see in the pic that the stub axle has been changed and the old axle chewed up about .100 of the housing. The new stub axle looks like a rebuilt unit from LoneStar so I am assuming it has a hardened tip on it. The question is where is the play coming from. Clutchpacks normally don't wear more than .050. You need to find out what is causing the play.
Mike
Mike
Thread Starter
Racer
Joined: Dec 2011
Posts: 284
Likes: 4
From: Philadelphia Pennsylvania
Need more info about the diff in the car. I can see in the pic that the stub axle has been changed and the old axle chewed up about .100 of the housing. The new stub axle looks like a rebuilt unit from LoneStar so I am assuming it has a hardened tip on it. The question is where is the play coming from. Clutchpacks normally don't wear more than .050. You need to find out what is causing the play.
Mike
Mike