Outer Limits 4x4 Board

Ive decided to shim up my LSD in my GQ to make it a bit tighter. Its the first time ive played with an LSD diff (have opened a few open centres).

I added two 0.5mm shims, one either side. I *may* have put them in the wrong place, but it will still work. If i have them in the wrong spot, let me know, i didnt remove anything from the diff, just added the 2 shims.

Im hoping that someone might get some help from this post!

Ok, first up i have the centre held in a bench vice. I have punch marked the bearing adjustment nuts so that the bearings will be exactly as they were before I touched anything. as well as the bearing clamp.

Remove the locking tab. From my punch mark, the bearing adjustment nuts took 4 full turns to remove.



Once adjusting nuts are removed, remove the two bearing clamps. The centre is now able to be lifted out



The ring gear bolts now need to be removed, they are tight! I clamped the centre into a bench vice and used soft copper jaws



Now the ring gear can be removed, Then turn the centre over, and there are three phillips head screws to remove. They are also tight, I used an impact driver to remove



The centre can now split open, and the clutch packs and sun gears can be accessed



I then turned over the centre on the bench (put hand over so everything doesnt drop out while turning over) then carefully let the contents of the centre come out onto the bench. I made sure everything stayed in order, and this is important



I then removed the top shim/spacer to create a template for the shims. I cut my own shims, but i would reccomend just buying the shims you want, much easier









Once shims were cut, (now this is where i may have put them in the wrong place) I put a shim on either side, of the centres contents. So my first shim was the first thing to go back into the empty centre, and 2nd shim was the last thing to go in before closing back up. Pic shows all of the contents of the diff placed back in, in the correct order, then my shim last to go on.



I then closed it up, and there was a gap, (there was a gap before i put any shims in also, once the three phillips screws were removed it 'sprung' open) and with the assistance of three g-clamps i closed it up the gap and placed in the three screws. I didnt want to close the gap with the screws as i didnt want to risk damaging the heads because it was pretty tight.



I then put the ring gear back on, in the exact position it came off. and used blue loctite threadlocker. I torqued the bolts up to 150NM



Now the centre can go back in, and fit the bearing outer race, and the bearing clamp finger tight.



Then screw the bearing adjusting nuts back in, the same amount of turns (using punch) they took to remove, mine took 4, and line up the punch marks (ensure you put everything back into the same side it come off).

Then do up the clamp bolts and fit the locking tab.




Done!

Any critisism is welcome. If i should have done something a different way, let me know.

Mike

hey very good work i like the attention too detail i will be shimming my lsd up too let us know how it goes and if u have any problems and i am unsure if this procedeure is correct but everything looks good.

I've heard you can get em tight enough to chirp tyres around corners. How much tighter did that one shim make it Mike? And what is the thickness of it?

Rowen

It's all fitted into the diff housing, but I ran out of sun light so didn't get a chance to add diff oil and test it.

The shim is 0.5mm, I used 2 so it's a total of 1mm extra shim in the diff.

Before I shimmed it, if I had one of the rear wheels jacked off the ground I could easily turn the wheel by hand. Now, I can't turn it at all by hand. It would easily drive off the Jack in 2wd with a wheel of the ground.

Thanks for the thread Mike, very informative. I'll use the steps to help with mine.

BadMav wrote:Thanks for the thread Mike, very informative. I'll use the steps to help with mine.

X2 mate, i'll be copying this info. I've been wondering how to do this exact job. let us no if you have any problems

Took the GQ for a run today and the diff is locked solid.

I will be removing the centre again to fit thinner shims, probably 0.2mm this time. I suppose 1mm total was too much!

I know hobzee used to sell 0.7mm shims, and from his website it sounds like you need to remove shims. But in my diff there were no actual shims (none around 1mm or thinner anyway) Does anyone know if you are meant to remove anything?

Locked solid, thought you could do it!!!!

Try driving it around for a few weeks, it may relax some tension and be a good lsd. You've gone to all the trouble of setting it up thus far, see what happens.
With my last gq I had the diff tightened twice, the first time was good but loosened after a short while, the second time was locked solid and still skipping tyres a year later. Great offroad but required a controlled driving stye on road. Hard on tyres and rear end bushes.
I to need to do the diff in my current gq, what material did you use to make the shim.
Good write up, done well!

cheers.

I had same trouble as eighty8, if you shim them with ability to lsd they only last one trip and they are the same as standard lsd. If you shim it to lock it will stay that way but a pain to drive. So after shimming it to lsd twice you will probably lock it up or go buy a locker. I figured it was a lot of work for little gain

I used stainless steel. It's actually shim material used for alignments of machinery.

Driving with it locked is no real issue for me. I drove a Sierra daily for over a year with a welded rear diff. Only problems for me are the crap turning circle on road, tyre wear, and it rips the shit out of the grass I park on in my front yard!

I will leave it as is for a couple of weeks. But I will eventually open it up and put thinner shims in.

Mike

cant wait to do this too mine just wondering where u got the shim material from? and if ur gonna pull those shims out would u consider getting rid of them?

I got it from work.

Really couldnt tell you where you would buy shim material from, but there is no reason why any thin sheet metal wouldnt work. Have heard of someone on this forum mention using the ends of a milo tin to lock the diff. Not sure how thick the metal is, but good idea!

I'll let ya know if/when i take them out.

no worries greatly appreciated using just sheet metal is a good starting point thanks again for a detailed post

Good write up mate preety much saved me having to do a write up a while ago hehe, and i agree buying them save alot of hassle, i used hobzees shims .7mm, i brought 4 but could only fit 1 in 1 side, it made it like a locker. Your write up should be a sticky in like a D.I.Y section of the forum as it will really help alot of those D.I.Yers (like myself)

sweet thread mate ill youse it when i do mine in due course.... i think youve just made it a hell of alot easier for alot of people wondering how to do it cheers

Great write up.
Be interested to see what the tecsperts say.

I had mine shimmed up by PGS in Mornington, they use the same shimms a Hobzee (not sure what size).
It was locked solid at first , now it slips a bit, but wheels still chirp on the tar when driven agressively.
Used castrol LSD oil which also made it shudder a bit when slipping, was told by Joel at PGS to change it to Penrite LSD oil (i think).
Haven't changed it yet because my son rolled the car, will change it when the new cab goes on.

Cheers

Hey guys, i've currently got my diff centre out at the moment just doing a bit of work.

Can anyone else point me in the right direction to buy these premade shims other than this hobzee fella?

oh and in brisbane would be a big help!

mine chirps during a uturn but still putting in the locker.

How did this turn out? Did you re do it or did it loosen up eventually? Considering getting it done for myself

Great write up, thank you very much.

How does this effect the backlash?

Pep

Managed to install two 0.7mm shims today however realised I've made a bit of an error. I recorded how many turns of the carrier retaining screws but not the bearing retaining nut I had marked them and so I tried the 4 turns mentioned on both mud rhino and outer limits but unfortunately it's way too tight. Looks like it's off to a diff shop to get the backlash etc set correctly