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  • Installing a ring gear on a Quaiffe LSD

    This subject comes up now and again. I'd like to thank erbair for letting me use his Quaife for the write up. This is a pretty advanced project but if your careful anyone should be able to do this.

    So first things first. You have to remove your old diff. from your trans. Different Racing has a good article on there site covering this so I won't repeat.
    Next you Have to remove the old ring gear. I choose to cut the rivit heads off with an end mill you may choose to grind the heads off with a grinder ether way you want to secure the stock diff so it won't move.

    I used the bed of a mill at work. But a vise would work. Be careful not to damage the teeth on the ring gear. Also I wouldn't drill them out. The pointy end of the drill hole will make it harder to use a drift to press out the rivit .But I'm getting ahead of myself.

    So I used a long reach center cut 5/8" end mill. And eyeballed the center of the rivits and drilled/milled off the heads.

    Next I moved to a press and pressed the body of the rivit out.

    Be very careful here. You have to use some sort of drift. If it slips it could impale you. Also the bodies aren't pressed in to hard. I tried to pound them out with a hammer but no go. It took about 5 tons (according to the press gauge) to get them out.

    Next I put it on a padded table and with a soft hammer tapped the ring gear off.

    Toss the old diff in the recycle bin.

    Next clean up the old ring gear and the new LSD. Use some sort of mild solvent. Also blow it all off nice and dry.

    Now tighten your bolts by hand. I use 91239A612 bolts from They are a 12mmX1.75 *20mm long button head bolt. They are also ISO 10.9 which is equal to US grade 8. I found out that a regular headed bolt is to thick and will rub the case.

    There is a land that will help you line up the ring gear. On my diff there was no play on this one there was a bit of slop. I figured about .010" movement. No worries.

    So set up the assembly on some V blocks and get your self an indicator. Spin it around and check the run out. At this point you can use a piece of brass or aluminum and tap the ring gear in place. Be gental. I figure +/-.004 or so and your golden. If you cann't tap it in you can mark the diff with a Sharpie and reinstall the ring gear at a 90 or so. I did a run out check on the diff itself with no ring gear and it ran out .001" Saturn uses a bevel cut helical gear so in reality you could be double that and not feel a thing. Personally I'm a bit picky.

    So now after the run out check. bolt it back down and remove one bolt at a time.

    Use some red Loctite and coat the threads and reinstall the bolt. Tighten them with a wrench.

    Now torque them down in a criss cross pattern. I contacted Quaiffe on this and I couldn't get a strait answer on what to torgue the bolts at. Torque is based on what your tightening into. For example aluminum takes a lighter load then say H-13 tool steel. All those torque specs you see in service manuels are for bolts them selves normally a grade 5 or so. So don't relie on that info. But don't get your panties in a wad I talked to an engineer at work who knows his stuff and he figured that 65 foot pounds will do the trick. I broke it down to 25 then 45 and then 65 with one more pass at 65.

    Once the torque is finished coat were the bearing goes with some anti seize

    Then press on the bearing. Do not press on the outer race you will damage the bearing. I made a special press adapter that presses on the inner race and clears the hub.

    So that should do it.

    Now when your done and ready to reinstall dump some ATF on the bearings and inside the diff. Also as you put the trans back together don't freak out if the bolts hit the case. You have to put it all together and this clip pulls it into place. If you get the trans all back together and it still hits the case take it out and try again. If you need any help PM me (TimT)
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