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1994-2004 Land Rover Discovery Upgrades - Weak Links, Strong Fixes

Front Passenger Side View
Harry Wagner | Writer
Posted October 1, 2007
Contributors: Bill Davis

23 Upgrades For '94-'04 Land Rover Discoverys

From the Camel Trophy to the G4 Challenge, Land Rovers have long been recognized for their off-pavement prowess. The '94-'99 Discovery and '99-'04 Discovery II are some of the best of the bunch, sharing many of the same attributes as the famed Range Rover without the upscale price tag. The low gearing, solid axles, and flexible suspension provide Discos with a very capable platform that can perform even better with the parts and upgrades detailed below.

Weak Link: Front Driveshaft
Models Affected: All
What Happens: First-gen Discoverys have some odd front driveshaft geometry that can create problems with even minor suspension lifts. The U-joint angles are unequal, the differential and transfer box are offset, and the U-joints are clocked 40 degrees out of phase. Land Rover solved the front driveshaft geometry problems on the D II by adding a double-cardan (CV) front driveshaft. Unfortunately, they created an even worse problem. The new driveshaft is not serviceable, is in close proximity to the catalytic converter, and the air-conditioning compressor drains onto the shaft. In other words, the catalytic converter bakes all of the lubrication out of the shaft and you can't add any more. Unfortunately, the shaft will frequently break completely in half with very little warning and will usually knock a hole in the side of your transmission.
Sturdy Fix: Custom-built double-cardan driveshafts are available from Great Basin Rovers. These solve the vibration problems in the Discovery and are completely serviceable for the D II. Great Basin Rovers also sells a driveshaft service kit to upgrade the D II front driveshaft to fully serviceable if you want to save money and install the parts yourself.
Contact: Great Basin Rovers

Weak Link: Rotoflex Joint
Models Affected: '99-'04 Discovery II
What Happens: A rubber coupler called a rotoflex joint is fitted between the transfer-case output flange and rear driveshaft to attenuate driveline vibration and smoothly transfer torque to the rear axle. Although this makes for a quiet ride on the street, the rotoflex joints rapidly fail when subjected to high angularity and binding on the trail.
Sturdy Fix 1: A factory replacement rotoflex joint is available from your local dealer. The joints are reasonably priced, don't take up much cargo space, and are easy to change out on the trail.
Sturdy Fix 2: An even better solution, although more expensive, is to scrap the rotoflex joint entirely and convert to a standard U-joint. Atlantic British offers a kit that contains all the necessary parts to bolt a U-jointed driveshaft and yoke on your Discovery.
Contact: Your local dealer or Atlantic British

Weak Link: Center Differential
Models Affected: '99-'03 Discovery II
What Happens: The Discovery II has a center differential in the transfer case similar to an axle differential. The center diff transfers power to the front and rear axles for full-time four-wheel drive. Unfortunately, the differential does not come with provisions from the factory to be locked for a 50/50 torque split when off-pavement. The '99-'01 1/2 D IIs have the internal provisions to lock the transfer case, but no method to engage. The '01 1/2-'03 D IIs must have the entire transfer case swapped out in order to have a locked low-range.
Sturdy Fix: In its final year of production, the D II came from the factory with a center diff-lock shifter to lock the center differential. The cable-actuated '04 CDL shifter is available from Expedition Exchange and can be retrofitted to '01 1/2-'03 D IIs. The CDL Kit is composed of all Land Rover parts and contains everything one needs to lock one's CDL-ready transfer box, including the shifter knob, '04 CDL shifter body, cables, and fasteners. The '99-'01 1/2 D IIs only need to be retrofitted with the necessary parts from a DI.
Contact: Expedition Exchange

Weak Link: Watts Linkage
Models Affected: '99-'04 Discovery II
What Happens: During articulation, the rear Watts linkage can bind. This limits wheel travel and can eventually fatigue and lead to failure of the part if not addressed.
Sturdy Fix: Rovertym produces a Watts linkage that is constructed of heavy-duty 1/2-inch-wall tubing for greater strength. Additionally, the new linkage is curved to prevent binding against the rear axle bracket, and like all Rovertym products, it is made right here in the U.S.A.
Contact: Rovertym

Sources

Rovertym Engineering
Durham, NC
866-768-3786
www.rovertym.com
British Pacific
Burbank, CA 91504
818-841-8945
Rovers North
800-403-7591
CV Unlimited
www.cvunlimited.com
Expedition Exchange
Los Angeles, CA 90021
Atlantic British
www.roverparts.com
DAP Enterprises
www.dap-inc.com
Great Basin Rovers
www.greatbasinrovers.com
Rock Ware
www.rockware.net
Rover Tracks
www.rovertracks.com
Slickrock Fabrication
www.slickrockfabrication.com
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