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LSD centre installation

shmickmik

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I have had a searcha nd realise its smarter to get a diff place to install your LSD but i am pretty confident i can do it myself. The only issue i have is due to the shims.

As long as i pull out an LSD from another diff i just need to make sure i grab the shims along with iit right? The matching shims in the exact same spot in my diff and there should be nothing to worry about right?
 

delcowizzid

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nah each diff will require different shims to suit.thats why its best to let the diff guys do it so they can swap shims till its right
 

shmickmik

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Ohhh thanks for that mate :) I have been searching diff and lsd threads for ages now and it doesnt help when people just saying "UTFSE and look at the ALL YOU NEED TO KNOW ABOTU DIFFS THREAD"

Just while your here, can i ask, when you shim an lsd centre are they the things that looke like big washers that go on the sides of the centre itself? And is it the shims job to keep the centre nice and snug in the diff housing? I was just thinking maybe if i wanted to do it myself, is to just goto the wreckers and pull out lots of different shims and sit there trying to find the best combo?



Or i could just get it done right lol They wanted $250 for a complete LSD diff anyway.. oh well
 

Calaber

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Hi Schmick

The shims are the "big washers" you refer to and used to align the diff centre with the pinion. They vary in thickness by thousands of an inch and allow for tolerances in manufacture. Even though they may look the same, chances are they vary by very small amounts. A micrometer would be the only way of accurately measuring them.

No two diff housing are exactly the same and that's why you can't just pull the centre and shims from one housing and slot them straight into another housing. Sure, they may fit, but it doesn't mean the diff will be set up correctly.

Setting up diffs is very exacting and requires certain special tools. You need a dial guage to accurately measure and set the pinion to crown wheel lash. The pionion gear has a collapsible spacer between the bearings that is designed to crush slightly as you tighten the pinion nut, to ensure the correct pre-load tension on the bearings and to set the pionion to the correct depth in the diff housing. You need to be able to lock the pinion whilst tightening the nut, and a spring scale or some measuring device to measure the amount of pre-load on the pionion bearings.

The pre-load and pionion to crown wheel lash are vital settings to ensure correct and durable service from the diff. Unless you know exactly what you are doing, and have the proper tools, it's beyond the average back yarder to tackle this job properly.

Hope this helps to explain why building diffs is a specialist job.
 

greenfoam

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I put mine in, without any special tools, I only said well..... that's about right and I also changed the gear set, I used some bearing blue to see where the teeth were running and adjusted it up untill it was how it should be. First time I've attempted it and the diff is still going, it is a little bit tricky I guess but not that hard, so long as you're an above average monkey I'd give it a shot backyard style. Compared to building a Space Shuttle it's quite simple :) and other people have done that. Believing you can do something is 99% of the battle with anything really
 

centy

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If you want to fit a lsd centre your self you would have to use the crown wheel out the diff that you want as lsd then keep swapping shims till the backlash is right. A dial gauge would be best but maybe if you are confident you could do it by hand. I would want to use prussian blue to check the gear contact either way. Then you know that the teeth are contacting correctly.
 

greenfoam

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I think if you have a play with the diff BEFORE you pull it apart and get a good feeling for how much everything moves then you will have a good idea of how it should feel once it's back together
 
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