I bought this TH rear from a friend of a member some time ago, and have finally gotten around to checking it out more thoroughly. The lash seemed very tight, so I pulled the cover off and applied some yellow juice. The pattern doesn't look right, and if I am interpreting it correctly, the Ring is too close to the Pinion?
I tried swapping the existing shims end for end, but that made it even tighter. What say the pros?
Thanks,
Randy

 

First question-
What is the rear you are working on?
What is too tight to you? We need a measurement to work with ... is it .003? .006? .010? .015?
looks like a used gear as it is hard to tell in the picture.
DO not like the drive side with only 1/2 the pattern and the diagonal track across the face.
(makes me feel these gears were set-up wrong at one time RUN then reset in another housing again and this is as good as it is going to get...You might get noise...
The drive side appears that it WOULD swipe correctly IF it was not worn... Just appear either the gear was heavily lead footed for years.
Coast side is decent for a USED gear.

 

This is a 3.90 posi (TH code) rear from a 66 442. The gears are well used, but no visible pitting. I lent my dial gauge to a friend, and need to get it back, so I don't know the exact lash right now, but compared to a similarl one I installed in my Red car a few months ago, there is very little lash (feels like less than .005). I will post the exact number as soon as I am able to retrieve my gauge.

 

I was able to check the lash just now, and I was way off on my 'hand indicator'. The lash is ~.014".

 

Yes you need to figure out why .014 is the lash. Factory would never be at that. 6-8 is factory. Up to .010 is acceptable for used.

So you need to pull the axles.
pull the bearing caps.
Now see how easy or hard it is to pull the posi and ring gear from the case saddles.
IF it is fairly easy and you can pull by hand...it is too loose and you could have worn carrier bearings.

IF it is tight... You need to measure the left and right shim / shim pack and maybe some one over time had the unit out and swapped them by mistake.

START there and see what you get. Jim

JD

 

I've already had the carrier out, and it came out fairly easily. I had to tug a bit, but no tools necessary.

 

Look at the races and see if they have little wear ledge if so they need replacement. If not then get .005 shim on the driver side and get the carrier back in spec and double check the pattern. If the shim is a .237 you will need to find a .242. Or you will need a aftermarket shim set. I have them for 5.00 plus shipping.

The carrier being loose in the saddles side to side is likely what is giving you the bad pattern and it will ONLY GET WORSE. Jim

 

I pulled the carrier out to examine the races. There is no wear ledge, only a difference in color. The thin area at the outside that does not contact the bearings is bright metal, the area where the bearings roll is a light shade of grey, like gunmetal, with very faint very small lines running in the direction of the bearing travel. I cannot feel the lines, only see them. If the bearings sound O.K. from my rookie description, then I will take one of the shim sets. If they sound wrong, do you sell the bearings? (TIMKEN LM501314 in it now). Funny thing, there are some of the small faint lines on the outside of the race as well, almost as if it was turning in the saddle just a bit........

 

Ok well if you do not have enough pre-load YES the bearing could spin in the saddle...NOT good... This is why I say you need to shim it up. THIS HAPPENS to all rears sooner or later they loose there pre load from wear. NOTHING you can do but re-shim and go. If left unattended it will take out the entire rear. Were talking like 10 -15 years...lol. UNLESS your drag racing every weekend or road racing stuff like that. OR if you are just a plain old LEAD foot every light you need to do a burn out...lol. ME!

Your bearings differ from driver to passenger. You gave me the driver side bearing and race. If you are going to do it...Do them both.

45.00 for 2 bearings and 2 races. 45.00 on the shims you will need 2 sizes on them also. JUST in case. Got ya covered on that.

Shipping - where are you? zip code.

 

Hmm, both of the bearings are the same, (TIMKEN LM501314). My Zip is 83687.

 

Monzaz, please don't leave me hangin here.................

 

Anyone?

 

Replace the bearing and reshim. Yes. You have to put the rear back into spec.
You said the race appeared to have spun in the housing saddle so this is all you can do. If this were the jdrace site i would have stayed tighter on the return threads... I do these other sites the best I can when I have time.
It is free info you know.

Yes both bearings will be the same in MOST rears except Buick 8.2 and full size car 9.3. Jim