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Merkur XR4ti: Limited Slip Differential Andrew Totolos installs a limited slip differential on an American car with German roots — the turbo-charged Merkur XR4ti. From "Tricked Out" episode DTRK-405

(Continued from page 2)

Andrew compares the stock differential to the limited-slip version.

Convert Open Differential to Limited Slip Differential

The open differential has been removed from the car, and now it's time to begin the conversion to the new limited slip differential. First, the housing must be taken apart, and the old differential removed. Then the conversion takes place.

Materials and tools:

limited slip differential
standard mechanic's tools
speed wrench
rubber mallet
angle steel
drift punch
shop press

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	Figure B
	Figure C

Steps:

To begin the differential conversion, the first step is to take apart the differential housing and remove the old differential.

• Use a speed wrench to quickly remove the differential cover bolts (figure B).

• When all the bolts are removed, use a rubber mallet to break the cover loose and remove it.

• Next, remove the axle stubs from the differential housing. The stubs are held in place by a few snap rings. Because they're so tightly placed, Andrew uses a modified pick tool to grab the snap rings (figure C) and pull them out. He also uses a screwdriver for leverage. It will take some patience and effort, but the snap rings will come out.
  

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  	Andrew removes the castle ring.
  	Andrew removes the pinion gear.

• With both clips gone, slide out the axle stubs.

• Use a piece of angle steel to crack loose the castle rings, which are big reverse nuts that hold the differential in place. Loosen them with the angle until you can spin them free from the housing.

• Now that the differential is apart, transfer the ring from the open differential to the limited slip. The reason for this is that the ring gear and the pinion gear inside the housing are a matched set. If those are changed, it will change the gear ratio of the car. We don't want to do that for this project.

• There are a lot of bolts to remove to change the ring gear. Remove them in a cross pattern, as when tightening alloy wheels, to keep from warping the pinion gear.
  Use a drift punch to work the gear down off of the spine.

• Still working in a cross pattern to keep from binding up, slide the ring gear onto the new limited slip differential, and carefully line it up with the holes in the mounting plate.
  The gear is a tight fit, so walk the gear on slowly to make sure it's going on straight.

• Start the first bolt where the gear is closest to the flange. Instead of tightening it, move two bolt holes over and start the next one.
  

  	Figure D
  	Figure E
  	Figure F

• With the two bolts started, flip the differential over and use a soft mallet to tap the opposite side down enough to start another bolt.

• Continue this process until every bolt is started. Then pull the gear up to the flange by tightening the bolts a little at a time, always moving across instead of next to the bolt being tightened.

• When it looks like the gear is going on straight, pop in the remainder of the bolts and lock the gear into place (figure D).

• After it's seated against the flange, torque all of the bolts to make sure everything stays in line (figure E).

• Once the ring gear is on, remove the new axle stubs to install a fresh set of carrier bearings. These are press fit bearings, so they fit really snug. There are a few ways to get them on. First, you could take a pipefitting, put it over the bearing, and with a hammer tap it down. Doing this, you might damage the bearing. Andrew decides to use the shop press (figure F.

• Before pressing the bearings on, squeeze a little gear lubricant on, which will protect both the surfaces as they bearings slide into place.

• Make sure that everything is lined up perfectly, and then press the bearing down until it's snug against the unit.

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