Land Rover Lr3 Disco 3 Front Drive Axle And Differential Landrover Com Manual

							Front Drive Axle and Differential  
GENERAL  
 
 
 
The front differential converts the angle of drive through 90° and distributes drive, via the front drive halfshafts, to the 
front wheels.  
 
The front differential for the V6 and V8 petrol variants have the same output ratio, but the output ratios for the TdV6 are 
different, depending on whether automatic or manual transmission is fitted.  
 
The front differential is mounted on the LH side of the chassis.  
 
FRONT DIFFERENTIAL ASSEMBLY  Front Differential - Exploded View  ItemPart NumberDescription1 -RH front drive halfshaft2 -Front differential assembly3 -Front driveshaft4 -LH front drive halfshaftPage 1 of 4Contents Page1/17/2004http://gtr.franchise.landrover.com/extdealerlrprod/xml/parsexml.jsp?XMLFile=G421063&... 
						

							 
 ItemPart NumberDescription1 -Protection cap2 -Mounting bush assembly3 -Seal4 -Bearing assembly5 -Front tube6 -Bolt, 4 of7 -O-ring8 -Drain plug9 -Bolt, 14 of10 -Cover assemblyPage 2 of 4Contents Page1/17/2004http://gtr.franchise.landrover.com/extdealerlrprod/xml/parsexml.jsp?XMLFile=G421063&... 
						

							 
The casing comprises two halves with machined mating faces. When assembled, the cast iron casing halves are sealed 
with a thin film of Loctite 5999 sealant and secured together with fourteen bolts. A breather tube is fitted to the casings. 
This allows a plastic tube to be fitted and routed to a high point in the engine compartment, preventing the ingress of 
water when the vehicle is wading.  
 
The RH casing is fitted with a drain plug. The front differential unit contains approximately 0.7 litre of oil for a dry fill.  
 
The differential is a conventional design using a hypoid gear layout. This employs a hypoid bevel pinion gear and crown 
wheel, with the pinion offset above the centre line of the crown wheel. This design allows for a larger pinion gear to be 
used, which has the advantages of increased gear strength and reduced operating noise.  
 
The front differential is available in three ratios. V8 and V6 petrol engine vehicles use a front differential with a final drive ratio of 3.73:1 and TdV6 diesel engine vehicles use a final drive ratio of 3.07:1, for vehicles with manual transmission, and 3.54:1 for vehicles with automatic transmission. Changing the number of teeth between the crown-wheel drive gear and 11 -Cover seal12 -Roller bearing cup13 -Bearing preload spacer14 -Taper roller bearing15 -Bolt, 10 of16 -Differential case17 -Roll pin18 -Gear and pinion assembly19 -Taper roller bearing20 -Roller bearing cup21 -Shim22 -Collapsible spacer23 -Roller bearing cup24 -Taper roller bearing25 -Oil seal26 -Inner deflector27 -Outer deflector28 -Flange29 -Pinion nut retainer30 -Pinion nut31 -Mounting bush assembly32 -Axle mounting bracket33 -Data label34 -Breather tube35 -Cap36 -Fill plug37 -Bolt, 3 of38 -Taper roller bearing39 -Bearing preload spacer40 -Roller bearing cup41 -Thrust washer42 -Planet gear43 -Shaft44 -Sunwheel45 -Thrust washer46 -Mounting bush assemblyPage 3 of 4Contents Page1/17/2004http://gtr.franchise.landrover.com/extdealerlrprod/xml/parsexml.jsp?XMLFile=G421063&... 
						

							pinion gear changes the ratio.  
 
The differential comprises a pinion shaft and hypoid bevel gear, a crown wheel drive gear with an integral cage, which 
houses two planet gears. Two sun wheels are also located in the cage and pass the rotational drive to the drive shaft 
shafts.  
 
The pinion shaft is mounted on two opposed taper roller bearings with a collapsable spacer located between them. The 
spacer is used to hold the bearings in alignment and also collapses under the pressure applied to the pinion nut. This 
allows the nut to be tightened to a predetermined torque, which collapses the spacer, setting the correct bearing preload.   
The pinion shaft has an externally splined outer end which accepts and locates the input flange, which is retained by the 
pinion nut. The opposite end of the output flange has an internal spline which provides positive location for the front 
propeller shaft. The flange has an external O-ring seal which seals against the front propeller shaft shroud preventing the 
ingress of dirt and moisture into the splines. An oil seal is pressed into the LH casing and seals the input flange to the 
differential unit. The pinion shaft has a hypoid bevel gear at its inner end which mates with the crown wheel drive gear.  
 
The crown wheel drive gear is located on the carrier and secured with ten screws. The carrier is mounted on taper roller 
bearings located in each casing half. The bearings are press fitted into the casing and a spacer is located on the outside 
face to set backlash and apply preload to the bearing.  
 The carrier is fitted with a shaft onto which the two planet gears are mounted. The shaft is secured in the carrier with a roll pin. The sun wheels are located in pockets within the carrier and mesh with the planet gears. Thrust washers are located 
between the carrier and the sun wheels and hold the sun wheels in mesh with the planet gears. Each sun wheel has a 
machined, splined, bore to accept the drive shaft. A groove is machined in the bore to locate the snap ring fitted to the 
drive shaft, providing positive drive shaft location.  
 
Differential Operation  The operating principles of the front and rear differentials are the same. Rotational input from the propeller shaft is passed via the input flange to the pinion shaft and pinion gear. The angles of the pinion gear to the crown wheel drive gear moves the rotational direction through 90°.  
 The transferred rotational motion is now passed to the crown wheel drive gear, which in turn rotates the carrier. The shaft, which is secured to the carrier, also rotates at the same speed as the carrier. The planet gears, which are mounted on the shaft, also rotate with the carrier. In turn, the planet gears transfer their rotational motion to the left and right hand sun 
wheels, rotating the drive shafts.  
 
When the vehicle is moving in a forward direction, the torque applied through the differential to each sun wheel is equal. 
In this condition both drive shafts rotate at the same speed. The planet gears do not rotate and effectively lock the sun 
wheels to the carrier.  
 
If the vehicle is turning, the outer wheel will be forced to rotate faster than the inner wheel by having a greater distance to 
travel. The differential senses the torque difference between the sun wheels. The planet gears rotate on their axes to 
allow the outer wheel to rotate faster than the inner one.  
 
SERVICE  
The oil used in the front differential is Castrol SAF-XO. The oil contains unique additives, which enhance the differentials 
operation. No other oil must be used in the front differential.  
 
Front Differential Serviceable Components  
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Halfshaft seals  
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Needle roller bearing assemblies  
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Chassis bush/fixings  
lLubricant.  Page 4 of 4Contents Page1/17/2004http://gtr.franchise.landrover.com/extdealerlrprod/xml/parsexml.jsp?XMLFile=G421063&...