I own a ’71 CJ-5 with a 4.3L V-6, SM465 manual transmission, Spicer 18 transfer case, and Dana 44 axles with 4.56 gears and Lock-Right lockers. The rear axle has a Warn full-floating kit and the Jeep has disc brakes all around. It sits on a spring-over suspension with Wrangler leaf packs and rides on QR78-15 Buckshot Mudders. After sitting for a while, the Lock-Right in the rearend won’t ratchet like it used to. What is a possible cause for it to stick and make the rearend act like it has a full spool? I have taken the diff cover off and I was expecting to find water in the differential, which would explain the locker not clicking or ratcheting when turning, but I found no water or rusted components.
JC R. Via email
Drop-in lockers like the Powertrax (powertrax.com) Lock-Right are a great low-cost and easy-to-install full locker alternative. It’s perfect for those that want to dip their toes into the aggressive traction-adder world without breaking the bank or committing to a gear setup. By design, these drop-in lockers are typically not as durable as their full carrier replacement locker counterparts. This is mainly because the drop-in locker simply replaces the differential gears and is fitted into the factory open differential carrier. In most cases, only one cross pin is used to retain the drop-in locker in the cast open carrier, where a full locker will typically have four pins that attach the locker to a much more durable machined-steel differential carrier.
Over time, drop-in locker performance and reliability can diminish. How long this takes depends on several factors including horsepower, gearing, vehicle weight, tire diameter, driving style, and gear oil cleanliness. There are several things at work here. The added stress can cause the cross pin to wallow out the cross pin bores in the factory carrier, which will lead to wonky locker operation and possibly catastrophic failure of the differential carrier. Inspect the cross pin bores. The pin should fit in them well; if there is excessive play or cracking around the bores, you’ll need to replace the carrier.
The small springs and pins used in the drop-in locker can fail too. It’s a good idea to check them periodically. Any broken locker springs or pins should be replaced. Broken springs and pins can cause the locker gear teeth to disengage unevenly or not disengage at all. It’s not a bad idea to carry spare springs and pins. They are inexpensive, small, and can easily fit in a tool bag or glovebox.
Contaminated oil could also cause faulty operation of a drop-in locker. The remaining oil oozing out of the differential in the photo you provided looks pretty dirty. Zooming in even reveals larger bits of sediment. There are also traces of water visible. You should thoroughly flush and wipe out your differential housing, extend your breather hose, and maybe even put a small filter on the end of the hose. This will help keep water and other contaminants out. Refill the differential with the proper fluid and check it regularly if you frequent deep water crossings and heavy mud.