Date: 04 Sep 95 08:27:38 EDT From: Mark Ritter (70472.1130@compuserve.com) Subject: Lock-Rite diff on DiscoAbout a week ago I installed a Lock-Rite locking diff in the rear of my Disco. The installation took about 6 hours (never been inside a diff before) and involved removing the spider and side gears and replacing them with dog clutches. Once done I took the vehicle out for a quick trial run. On the street there is no change except for a mild clicking noise as the outside wheel unlocks so that it can travel faster in a turn. This is not an objectionable sound and is minimized by using a heavy diff lube such a Lucas (no relation) oil stabilizer. I found a road construction site that provided an 18" embankment so that I could get two wheels of the Disco off the ground (the acid test). I stopped the vehicle going uphill with the right front and left wheels hanging in mid air and with the center diff lock off just idled up the embankment. The second test was a steep 30' uneven slope about 15" high. Normally this obstacle requires a good bit of momentum to overcome due to getting cross axled. The Lock-rite equipped Disco just crawled up with no tire spin or drama, and with much more control. I can heartily recommend this product for the auto box Disco. The company is conducting tests on other Rovers (I believe they already have a unit for the RR). The series vehicles had some problems initially due to the slop in their drivetrain but the company had devised a solution to this and is currently testing it.
The units run about $400 and for someone with a bit of mechanical experience installation will not be a problem. you do not have to reset the pinion as you use your original carrier.
The lock-rite is similar to a Detroit Locker but it is different in that instead of replacing the whole carrier you only replace the side and spider gears using the stock carrier. I have had no twitchiness on the road. I think this is due in part to the Disco's full time 4wd. The twitchiness that you have heard about [LA: on other SWB vehicles] is generated by the power going to the inside rear wheel when the outside rear unlocks. In a two wheel drive situation each rear wheel would provide 50% power to move the car until you came to a corner. As soon as the outside wheel unlocked 100% of the power is now going to the inside wheel which would tend to cause understeer. With full time 4wd the inside rear's share would go from 25% to 33% so the effects are minimal. About the only thing you notice is that it takes a little more pressure on the steering wheel to negotiate a turn.
Mark Ritter