About to do my own differential install...any tips?

[team39763]

I bought an Eaton LSD and I'm about to install it in a few days.  I had planned to install it tonight, but one of the new bearings fell apart in my hand.  I was standing there in my living room and holding the diff and spun one of the bearings, then the outer shell and all the little rollers came apart.  Anyways, I'm taking the diff to a nice shop in the next town to have the bearings pulled off and new ones pressed on.  Any suggestions on what brand?...I'll need a specific part# because none of the auto stores seem to know what I need.  We have an O'Reilly and an Autozone.  The bearing that fell apart on me was the "National" brand made by MOOG and Federal Mogul(MADE IN CHINA). 
   I'm using the same ring and pinion.  There were no shims when I pulled the G80, but I have a install kit with shims and gear paint.  I didn't touch the pinion, so it's still in place.  It's an 8.5 10bolt with Richmond 4.56 gears.

So here's my questions:
1. What bearings do I need for the diff?
2. Which way do the bearing caps go?  The rounded side towards the center or the to the outside? I know which is left and right, they just fell and I don't know which part is the top/bottom.
3. I don't have a dial caliper or anything, can I set up my gears by looking at the pattern on the gears with the paint?

[SUX2BU99]

Kudos to you dude for attempting this yourself! I've been looking into if I could attempt this and it looks kinda much to me, but that's just me. Go to ringpinion.com and check out their FAQ and Tech section, then read the installation instructions for a set of Yukon gears. It's pretty informative on what to expect and why you would want a dial indicator.

One thing that apparently was pretty imporant is if you are reusing the same R&P, you would have wanted to measure the backlash it was at, since you would want to reset your R&P back to that when you put them back in. If you don't, you run the risk of wearing out your R&P because a wear pattern has already been established.  I wish you luck though and a successful, quiet Eaton installation!  I'm out $2k for my rebuilt Eaton and R&P install and it's STILL not right 

[eventhorizon66]

If I ever want a gear change or to do another car, I'm definitely gonna try it myself.  My take is the main cost you are paying for is the tedium of pulling/reinstalling the diff/pinion until you get the shims right.  But I wouldn't be interested in attempting it without my own press (for pinion bearings).

[VileZambonie]

Just look up the bearings for your rear end application. Witness marks are important so don't mix up the caps. Get a dial indicator with magnetic base and digital caliper before you do the swap. Harbor freight has them cheap.

[team39763]

Thanks Vile, I'll check out HF and go ahead buy the tools I need.

Kudos to you dude for attempting this yourself! I've been looking into if I could attempt this and it looks kinda much to me, but that's just me. Go to ringpinion.com and check out their FAQ and Tech section, then read the installation instructions for a set of Yukon gears. It's pretty informative on what to expect and why you would want a dial indicator.

One thing that apparently was pretty imporant is if you are reusing the same R&P, you would have wanted to measure the backlash it was at, since you would want to reset your R&P back to that when you put them back in. If you don't, you run the risk of wearing out your R&P because a wear pattern has already been established.  I wish you luck though and a successful, quiet Eaton installation!  I'm out $2k for my rebuilt Eaton and R&P install and it's STILL not right 

For some reason I didn't even think about checking the lash or anything on the old carrier(not that I had a way to check at the time).  I may need to get a pro to help me do this.

If I ever want a gear change or to do another car, I'm definitely gonna try it myself.  My take is the main cost you are paying for is the tedium of pulling/reinstalling the diff/pinion until you get the shims right.  But I wouldn't be interested in attempting it without my own press (for pinion bearings).

I would gladly pay the price for a professional install, but the shops around here won't stand behind their work, not only that, they seem just as new to posi/gear installs as me.

[malibu795]

get your self some "blue" oo any off color grease if not supplied for contact pattern. or use the stuf supplyed.
measure back lash BEFORE removing the carrier. then reset the new carrier and ring back tot he previose back lash seting. this will allow and is critical to maintianing long R&P life.
you will need this to measuer back lash.
http://www.summitracing.com/parts/SUM-900016-1/


bearings get pressed on to the carrier ends..
no press..
here is a trick place the bearing in the over heat to ~350*F this will case the bearing to expand. about .001-.002"
place carrier in a bag. set bag and carirer in ice water. this will case the case to strink .001-.002"
then drop bearing on case allow everything to warm up/cool down nauturally ore palce a fan on it.
i would get this going before you start draining the diff and what not..

race. that is the part that slips over the bearing. the bearing goes on the carrier.

and yse you will need a dial indicator and base. see above link

caps.. if they dont have arrows. (they should they both face the same direction)  fit them up on the axle housing they should be flush on the in-board side.

and most important take your time or you will be re-doing it

[team39763]

I took out the old carrier and sold it weeks ago, so I'm already in trouble.  Can ya'll tell me this...how long will the ring/pinion last with the wrong backlash?  The truck isn't running yet, I just need the truck to roll back and forth so I can install the motor.  Once the motor is running, could I make one or two track passes to see how this gear works with the new trans/motor?  I may want to change to 4.88's or 4.30's.  This is a race truck and it's seen less than 50 miles over two years...in other words, it won't be driven much.

[SUX2BU99]

Well, I can only tell you my experience. My original 3.40 gears were re/re when my rebuilt Eaton was put in, and it lasted 4 days. But, that was about 100 miles of driving back home from the shop (about 50 miles) and then back and forth to the dragstrip (about 50 mile round trip), and then 5 passes that night at the drags. It wasn't even making any noise until the next day after the drags when I went for a rip up through the gears. And then once they do start making lots of noise, you could still probably get a few hundred miles out of it before a tooth breaks or something. You'll basically know if it's okay or not whether you have very audible gear howl.

[team39763]

Well I only plan to put about 5 miles or less on them and that's over a period of 2 weeks...driving to my test spot on the farm road.  I'm pretty convinced that I'm gonna need new gears anyway.  I just would like to test with the 4.56's before spending money on a new set.

[VileZambonie]

You need the correct pinion depth and the correct backlash or you won't only trash your ring and pinion you'll trash the differential too. Do it right the first time.

[team39763]

OK, you guys convinced me.  I'll do it the right way.

[team39763]

I need to install my motor/trans, can I slap the wheels back on and roll the truck about 3ft without doing any damage to the rearend(without the differential in there)?

EDIT: I just did it and everything seems ok.

[team39763]

I just ordered the tools, I guess it'll be a week or so before I get to mess with the gears.

[malibu795]

I need to install my motor/trans, can I slap the wheels back on and roll the truck about 3ft without doing any damage to the rearend(without the differential in there)?

EDIT: I just did it and everything seems ok.

yep as long as you are not apply power to them freewheeling them wont hurt them IE moving them around the shop and drive way.

[team39763]

Ok, I got all my tools from Harbor Freight.  I installed my gear on the carrier and oiled my bearing caps(they rusted while sitting in the cab of the truck).  I sanded them down with really smooth sandpaper. I have been reading several sets of instructions/write-ups, but one thing they don't mention is how things go as far as the shims/retainer(looks like a really thick shim).  Does it matter which direction that thick retainer thing goes in the axle tube?  I'm assuming the shims would go between the retainer thing and the bearing race?  I know I should have payed better attention when I pulled it all out, but it all came falling out when I took off the bearing caps.