I am having troubles installing my eaton locker i just got. It was used and came out of a 2004 f150 with the 8.8 3.55. It only has 1,000 miles on it so its not been used much. So being that he had it installed he shimmed it for the 8.8 diff, so why wont it fit in mine? The only thing i didnt get was the main big shimms that go outside the bearing caps, so im using my factory ones, why would they be different? He must of used his factory ones too... Is it supposed to be a pretty tight fit or is there supposed to be play? As my truck sits without wheels i hope that i can get this resolved with a little help from you guys! thanks

 

ok im not understanding the problem.

are u saying the carrier is too thick to use the oem .250" spacer?

needs to be very tight fit, the carrier needs to have no slop laterally

 

Alright, we got it damn near all the way in but it got really tight and wouldnt go any further. I couldnt get the driver side axle shafts in because it didnt seem like it seated all the way in correctly. The problem was, the locker unit wouldnt spin, it was locked tight. We got the passanger side shaft in and spun it but the unit itself didnt move, just the internals...It seemed like it was almost jammed in there, should i take a bearing shim out? If so where can i find a bearing puller and whats it exact term.

 

or should i try to grind down the .250 shims?

 

if your using the oem spacers and are bottoming out the pinion teeth into the ring, i would shave a few thou off if you cant locate enough shims to do the job. what you take out must be put into the other side.

so u are saying that the oem .250 spacer is too much correct?

for mock up u dont need to install shafts, just load the carrier, snug the caps and get your numbers.


yukon specs typical results 10 thou shim results 7 thou backlash. again typical not constant

 

i dont know if its necessarily the spacer, but yea its too wide. It has plenty of shims under the bearings so should i take one off each side? And see if it fits? Now that you say it might be bottoming out on the pinion, that brings something else up to look at...Could that possibley cause it not to slide all the way in? Its about a 16th of an inch short on the drivers side from being all the way in, but the passanger side went all the way in...But i was still unable to turn the unit, it was completely locked. I think it was too tight of a fit what do you think? we had to push it in pretty good and it definitally didnt fit like the factory unit did

 

yeah your too thick on that side. do whatever it takes to get that carrier to sit right. shim from there

 

so start the shim process from the passanger side of the carrier?

 

So i got the bearings pulled off and there is NOT any shims under the bearings apparently...I had tires plus do it for 1. For 2, the guy i baught it from said it had shims in it...I SWEAR i seen shims underneath the bearings...What does this mean? What i thought was there was shims under the bearings and thats what you adjust to get the proper fit? OR do i have to grind down the outer shims?? Somethings not right here, i swear i seen them underneath the bearings. Also, the bearings were DESTROYED when he took them off, cuz i got pissed off and made them show me what the bearing looked like. So they absolutely didnt take it off the right away ruined the baering and what im thinking is ruined the shims and are lying to me so they dont have to pay 144.00 for the kit...

 

The rears I have rebuilt/changed gears were similar, a 74 Ford Wagon and a 69 Chevy 12 bolt. There were no shims between the carrier and the bearings. You have to add shims to both sides outside of the bearings to get the carrier snug and the carrier has to be set where the ring gear/pinion gear backlash is correct. Then add maybe 0.010" shims to both sides to add some bearing preload. Install the carrier first. Then add shims to both sides to get it positioned correctly.
Having the problems you are having, I would suggest you get help from someone who has installed these before.

 

name of the game. sometimes the bearings just wont come off before they explode. usually its the wrong pull method.

spacer , shim, bearing cup, carrier , bearing cup, shims, spacer.

what you take from the left should be added to the right.

there is no reason with the 8.8 to use shims between carrier and bearing.



all in all you shouldnt have to shave anything, you should be able to find shims to do the job.

 

Well im trying to avoid buying a bearing kit so, i know of a gear and machine shop. I will go to them tomorrow with my stock rear end and eaton locker and tell them i need them both to sit at the same height when the .250 outside shims are added. So what i figure is, put the new bearings on, add the races to both differentials. Than on one, put the .250 inch shims on the bottom and top (standing the diff on its bearings/races) and have them machine the thicker quarter inch shim so they sit at the same height...We are talking a very very very VERY small measurment difference is the reason it wont fit. Does that seem like something that would work? That way the locker will sit in there just as the factory one did. Can you guys explain to me what backlash is?

 

backlash is the distance between gear teeth while one is in a fixed state. theres a write up somewhere on these forums you might wanna read.


yes you could have a shop plane a few thou off.

 

i think thats what ill do, i know of a few machine shops now, locally. By thou you mean in milameters right? That seems like too much, but i suppose you could always add a way thinner shim. Since the housing is the same size obviously and neither carrier has shims underneath the bearings, it HAS to be the size of the carrier, they are different. So i will just have to see how close they can get it while they are sitting side by side, then it should go in EXACTLY how the factory one did, with the right amount of lash, and such. Im crossing my fingers but i feel im going to need a back up plan, is there anywhere i can get just the shims and not the shim kit, ill only need a few if anything

 

erm thou(sandth)


check jegs, they should have a shim kit, or try locally