One of the best modifications you can do to improve the performance of your Clod based crawler is to lock the axle differential. This ensures that you get full power to both wheels on each axle at all times. Your ability to turn sharply will be reduced somewhat, but the improvement in climbing ability makes this mod well worth doing. (An upgrade to four wheel steering will help regain much of that steering ability.)
Let's briefly walk through some half dozen ways to lock a Clod differential. This assembly consists of the differential spur gear, three spider gears, two side gears, and the three pins that hold the spider gears in the spur gear. What we want to do is ‘lock' the two side gears to the spur gear, and effectively to each other. This will lock both wheels on the axle together.
We'll talk about homebrew methods that glue or screw these pieces together, and we'll show you several aftermarket replacement solutions.
With any of the homebrew methods you'll have to be careful not to get any of the glue materials on the spur gear surfaces or in the hex/shaft holes. Also, these methods require that you keep the gears aligned squarely on each other so the axle hexes and axle shafts do not want to bind when they rotate.
Let's look at the methods.
HOT GLUE - Craft hot glue can be used to stop the spider gears from turning and glue all the gears together. Glue is applied to the spider gears installed in the spur gear, then the side gears are quickly pushed into place as the glue cools.
Pros: cheap, cheap, cheap
Cons: relatively soft connection, will eventually fail under repeated use
(2) EPOXY – Various hardening epoxies (usually 2-part varieties) can be used in the same way as described in the hot glue method above. It's best to use a thick epoxy that won't droop or run much and you may want to epoxy one side at a time.
Pros: inexpensive
Cons: must be careful applying epoxy, will eventually fail under hard use
(3) JB WELD – This 2-part fix-it repair compound may be about the strongest way to glue your Clod differential. As with all the glue methods, more glue may be better, it just adds more weight to the assembly.
Pros: inexpensive, strong glue method
Cons: must be careful applying epoxy, stock hex sockets in side gears may strip and fail under hard use
(4) SCREWS – This method involves using three machine screws & nuts to bolt the two side gears together, stopping the spider gears from moving inside. The trick here is keeping everything straight and cleaning the debris off the gears before reassembly.
Pros: cheap
Cons: somewhat tricky assembly, stock hex sockets may fail under hard use
(5) SPIDER GEAR REPLACEMENT – Several aftermarket suppliers manufacture a set of delrin or aluminum pieces that screw together and sandwich the spur gear. These pieces replace the stock side gears and spider gears to form a locked assembly.
