Gary,
A year ago I rebuilt my 1972 rear diff myself. I haven't had any issues with it other than a slight whine at cruising speed. I recently changed the oil in it and the magnetic drain plug had no metalic residue on it. I am converting from an auto transmsission to a TKO600. While I was installing the new drive shaft I noticed I could turn the shaft back and fourth about a 1/16". This feels like alot and I am worried that with the manual transmission, it will feel jerky were with the auto it wasn't as noticable. I made sure the bearings were bottomed out on the carrier and was very careful with the set-up and pre-loads. I am not sure where the play came from. How much play is "normal"?

Thanks

 

I just PM'd you but in case you didn't get it.

Some questions:
Does it whine under load or when you let off on the gas?
what Backlash did you end up with?
What was the bearing preload, 15-18 in/lbs? Did you use a stock crush sleeve or go solid?
I see you used Yukon gears and fiber clutches. Yukon's are Randy's imported gears and I think they are spec'd at 6-8 BL? The fiber clutches are not the problem but I would remove them if you plan on any HP and hard driving, from what I've seen I will never use another set unless the guy states he wants them over the solid steels.
I would check to see what the backlash is now and figure the new gears worn off the coating by now and the BL opened up another .001-.002" Was the case in the housing tight?

 

Gary,
Here is the info I could find:
Whines when coasting
yes the preload was within 15 to 18 ft-lbs
A stock stile crush sleeve was used
The carrier was evry tight, had to use bar to lift out.
The final back lash was .017....this seems high
I also used carbon fiber clutches with 400lb springs.

What is the problem with fiber?

Thanks for your help!!

 

Oops,
The .017 was the BL of my spiders. My actual BL was .006". My pattern could have been better. It looked really good at first but after I tightened everything up it was centered deeper on the tooth.

The 1/16" on movement was measured at the outside of the yoke flange dust shield. The actual driveshaft movement would be less.

 

Are you sure about the backlash beign .017"? If so that is way too much. Randy's recommends 6-10 and I think 10 initial is too loose.( I did set my 69 to 8-10 and it was fine,but all the Toms I set up are now 5-6)

Fiber clutches

Here is a brand new one a buddy sent me for his rebuild.



When I opened the box and started to pick them up this is what I found



They were coming apart in my fingers. I spoke to several guys, including Tom and Kenny at Toms about these and no one really had good experience. For a low HP car maybe, but the only set I was convinces to use is in a 69 BB car. That one is the posi I posted about in rebuilding post. The case was cracked and instead of custom building a better case the garage who hired me for the job wanted to go with the Eaton assembly. All I could do was tell them about what I found and told them to use 2 bottles of additive. The car is on the road but I know the owner was never given the option on this, I know the clutches will start hammering once they start to wear.

Ok got a little side tracked on the posi. Sorry about that.

Did you take any pictures of the pattern when you setup the gears?

Here is a set of Yukon 373's I set up last year.







These were setup to 18 in/lb drag, 6-8 backlash. I set them lower then the 6-10 listed in the yukon manual.

 

Ah I just saw you posted while I did! LOL ok 6 is ok,17 was not. Whe I tune the clutches I set them to feel vs a given backlash, but if you use springs you have to check. 17 seems like too much spider bl as well though.

It is hard to "see" just what you have going on there, might not be anything. It may be the nature of the gear, is the yoke tight- no in/out movement?

I just installed 336 Tom's in my 72 and if I listen closely, over the Flowmasters I hear a very very slight whine. I had a bad set of 308's in this before so I was 100% critical on this setup. There was no varience at all in the spec's and I still have a minor whine. Now keep in mind people in the car do not hear it unless I point it out and then they have to really listen- too ****! I guess.

Lastly I'mnot trying to scare you about the clutches. You have them in there and may not have a problem- I would drive the car, swap the tranny and see how you like it. You can always drop the diff. If there is a problem it will not go away.

 

You are very kind to help me like this esp on a Sunday night!!
There is no perceptable in/out movement. I have a picture of the pattern I can scan into a PDF and send to you tomorrow. I may have the JPEGs at work. I crawled under my wifes 98 Jag and check the play and there was plenty. It does have 115,000 miles on it however....

What should I watch for regarding the clutches? You mentioned hammering, when would that occur? I had a moaning when turning so I switched back to the GM lube and additive and it went away. Was using a synthetic lube.

I also installed the heavy duty steel cap and bolts along with hardened tipped spindles from Tom's.

 

Here are a couple of pictures.

 

See you have some of Tom's parts in there.
The drive side pattern is longer in the root of the tooth, a thinner pinion shim would have brought it up. This may be your problem.

 

This is the pattern I had before I pre-loaded the pinion bearing. This pattern looked better. I am guessing that something was not seated all the way. Well I will see how it drives and go from there.