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Quaife LSD Install In A M56H

Published on January 29, 2011 by Johann
Remove as much oil from the gearbox as possible before opening the casing.  Put the gearbox on a bench or kitchen table with the clutch bell housing facing down.  Use a driver to remove the split pin so you can remove the small shifter lever from the gearbox.


Next unbolt all the 12 mm hex bolts which fix the case split.

Transmission removed

After that use a rubber hammer, a piece of wood or a metal bar (with care) to evenly loosen the top casing from the bottom.  There are several places on each corner of the gearbox where you can apply some force to split the casing. Make sure the force is applied evenly!!

 Open transmission

While lifting the upper half of the casing try to gently rotate the black shifter lever counter clockwise until the casing comes off.  

Differential open

Now locate the only 12mm hex bolt in the internals. The bolt is holding a metal bracket. Remove the bolt and the bracket.

Volvo LSD

In some cases, with older type geargoxes, instead of a metal bracket there will be a cast alloy part. If this is the case be as careful as you can since the alloy part can break when loosening the bolt.

Next locate a spring at the bottom of the shifter mechanism and look for a straight extention of the spring which is held behind a nipple. Move the extension over the nipple so the spring tension will be released, next remove the shifter assembly by turning it counter clockwise until it is free of obstructions.

After that the long metal lever bar can be taken out. In the middle of the bar there is a metal pin. With some gearboxes this pin sits loose and can be taken out after which the bar almost falls out of it's position. With some gearboxes the pin sits tight and can hardly be removed. In this case try to remove the bar using gentle force while moving it around a bit. Use care not to bend anything!

The next step I would advice to get an extra pair of hands. This can be done alone but it is difficult.  The next step the 3 gear packs need to be taken out.  Try to lift the 3 packs straight up while maintaining their position. Make sure to lift straight else the shift fork shafts might lock in their sleeves preventing the packs to lift any further. Use gentle force. Don't stress anything. The gear packs aren't light either. Once the assy is free of the sleeves you can take the packs apart and put them aside.  Leave the shift forks in their position and grouped with it's gear pack (I didn't..) or take pictures of the situation before taking things apart.

Next take out the diff gear and put it in a clamp.

I used rubber surfaced clamps to prevent damage to the diff gear.  Next step the bearings need to come off.  A special bearing puller is needed, space behind the bearings is very limited and your average K-Mart puller won't do.  On this picture borrowed from Michiel Nouwens you can see the type of puller best used

After removing the bearings and storing them in a safe place the bolts can be removed from the diff

And the diff can be removed from the gear by gently tapping it out using a rubber hammer.  Now degrease the bolts you just removed.  

Unpacked the Quaife diff from it's box.  The stock open diff is on the right.

After degreasing the gear I installed the Quaife diff in the gear and used 4 bolts to cross tighten the diff in the gear. Evenly tighten the bolts. Make sure the diff goes in straight else it might lock itself in the gear before it is fully engaged. Don't use any force or large tools. Just tighten the bolts lightly.  After the diff is in place remove the 4 bolts again and apply loctite to them. I have used mild thread locker 243.

Put the bolts back in and cross tighten them to 65 Nm - 48 lb-ft.

Put the bearings back on, same special tool is needed. Again don't slam anything out of line, be gentle.

Next put everthing back in to the casing in the reversed order. Take good notice of how the gearpacks need to go back in. Remeber that the shift fork shafts need to go in as straight as possible. Don't force.

Shifter mechanism in place.

Don't forget the magnet!!  Clean this surface on both the casting halfs. Make sure all the old silicone is removed. Use mild sand paper, I used a sanding block and sponge. Degrease well, apply silicone and close the box.  Before closing the gearbox make sure the shift fork levers on the shifter mechanism are all in their middle position.
While closing the box move the black shifter lever in the top casing all the way counter clockwise until it blocks. Align the top casing with the shifter shaft and the diff bearing and slide in back on. At some point you can feel some resistance at the black lever. While lowering the casing at this point the leaver should turn clockwise back in to the shifter mechanism.  Fix the 12 mm hex bolts some something near 30 Nm - 22 lb-ft

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