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TR2/3/3A when rebuilding a differential

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sp53

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This is a kinda crystal ball question, but when rebuilding a differential should I replace all 4 axle wheel bearing as a general rule. Or can I replace the 2 outer ½ axle bearings and call that good. My thought are the 2 on the end of ½ axle are going to have more wear because of the leverage from the length of the axle, but again I have no idea.

Thanks Steve
 
I am not familiar with this system. However, if something takes significant time to take apart I have always found that it pays to replace all expendable parts unless otherwise renewed very recently.
Bob
 
IMHO the bearings should be cleaned and inspected before a course of action is decided. Often
these parts are good for several hundred thousand miles ( IF THEY WERE MAINTAINED!!) Look for
pitting in the races ,then look over the rollers.
Mad dog
 
I agree with MD; there is no need to replace bearings if they show no wear or pitting. It's likely that the bearings already in the differential are better quality than the replacements you'll get from LBC parts suppliers, anyway. Also, you might not even get the right part. Dunno if TR3 differentials use the same bearings as TR4A ones, but the outer pinion bearing for the TR4A is a 15100 SR, which is hard to find, so a 15100 is regularly substituted. That is NOT the same bearing!


By the way, if you do need to replace them, note that bearings are generic. You can get the part no. off the bearing and buy a new one anywhere--even from Amazon!
 
Thanks you guys much appreciated. MD and Steve I feel the same way. Having never done this I was a little concerned, and yes Bob that is something I think about also. They are roller bearings and they make some unfriendly noises when I spin them by hand. I was able to find some NOS ones on Ebay for 30.00, so I bought 2 and will put them on, but I will look the old one over and compare when I get them pressed off. The generic number information is interesting Steve, and I will remember that. I found it to be true with some U joints for a tr3, so yes next time i hope.

Steve
 
If they rumble when you spin them, that's wear, so replace them. I could have been clearer--if there are any questions about them, they should be replaced, but if pristine, no need.
 
I've bought bearings from Amazon as well. Sometimes you can stumble on a heck of a deal on a known top brand like Timken or FAG.

I have also had decent results asking O'Reilly's or NAPA to special-order them for me. Sometimes you'll get someone who can't do a thing without year/make/model but the people who are willing to go the extra step can order them just with the part number.
 
When I was in college , I had a questionable diff that had to go into my old 60 tr3a. The bearings were slightly pitted
and it had a low growl at speed. Being a broke kid in school ,I cleaned it all up and filled the old lump
with 75/90 and a can of STP(half and half). This quieted it down a lot, as you might imagine, and it held together
until I had time to do it "right".
Years later I took it out, pulled it apart, but found no further signs of wear in the intervening 20,000 miles.
Did some head scratching and put it back like I found it with fresh STP/90. Went for 15 more years and 20K
before finally parting with her.
Mad dog
 
Inspect them thoroughly. You are looking for:

-corrosion
-race brinelling
-ball or race pitting
-damage to cages
-signs of scoring or abrasion

If they check out, then re-use them. The only berings I recommend replacing regularly are the tranny bearings. The tranny circulates a lot of metal from grinding gears, so they see a lot of abrasion that kills them early. The needles in the counter-gear seem to take the worst of the abrasion.
 
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