Replacing a Discovery 3 front differential - pictures

<span>When drained out, the differential’s oil looked black, discoloured and contaminated. The oil also had a burnt smell about it.</span>

<span>When drained out, the differential’s oil looked black, discoloured and contaminated. The oil also had a burnt smell about it.</span>

<span>The propshaft bolts are difficult to access and remove once they have been undone. Here, a magnet helps with their removal.</span>

<span>Using a bar, the propshaft is pryed away from the flange, then it is lowered and secured with a cable tie clear of the crossmember.</span>

<span>The crossmember under the front diff is unbolted, and then completely removed from the vehicle.</span>

<span>With the road wheel off, the axle stake nut is removed from the driveshaft, and the shaft tapped inward to free it from the hub splines.</span>

<span>The caliper assembly: pads, caliper and carrier, is unbolted and tied clear of the hub so as not to strain the brake hose.</span>

<span>With care, as it is easily broken, the securing screw is undone from the wheel speed sensor, before removing the sensor from the hub.</span>

<span>The steering rack track rod end ball joint’s securing nut is undone and then the ball joint is split from the hub knuckle.</span>

<span>The ball joint locating the upper arm and the knuckle is split, and the arm lifted with a pry bar to separate it from the knuckle.</span>

<span>The top of the hub knuckle is now swung out (still attached to the lower suspension arm) and the driveshaft separated from it.</span>

<span>The driveshaft is now free to be withdrawn from the differential, taking care to avoid damaging the components and CV joints and gaiters.</span>

<span>On the other side of the vehicle, the process is repeated to remove the left hand side halfshaft, before returning to work at the right hand side.</span>

<span>Unbolting the differential: With the right hand side driveshaft removed, the outer retaining bolt can then be undone from the driveshaft support tube’s mounting bush.</span>

<span>The driveshaft support tube is also located to the front differential by four bolts as shown, which are removed as well.</span>

<span>The driveshaft support tube is tapped free from between the diff and the chassis using a soft mallet. O-ring seen at right of pic is discarded.</span>

<span>The plastic breather line, from the breather stub coming out from the top of the front diff assembly, is unclipped and removed.</span>

<span>The differential is still supported at the front and on one side. This is the front housing support bush and mounting bolt being removed.</span>

<span>The diff is also supported at the side to the chassis rail by three bolts. Once they are removed, the diff will be free from the vehicle.</span>

<span>Assistance is needed to safely remove and lower the heavy front differential down and out from the Discovery.</span>

<span>Fitting the new differential: This new diff is seen from the left side (propshaft flange to the right of pic, red protective cap on breather stub, cap on left axle hole).</span>

<span>It’s a two-man job to handle the weight of the replacement front differential when manoeuvring it into position under the Discovery.</span>

<span>The differential is filled with the Land Rover specification grade of oil and the filler plug refitted as the rebuild progresses.</span>

<span>With the axles, knuckles and calipers on, new axleshaft stake nuts are tightened to torque, before locking the nut to the axleshaft using a small punch.</span>

<span>After refitting the propshaft and checking all bolts for correct tightness, the engine undertray and wheels are refitted.</span>

<span>Lastly the top of front diff breather pipe is checked that is clear and clean, and that its secured into position in the engine bay.</span>