4201 - Diff Ring
1387 - 1/4” x 3/8”
Plain Bearing
Lip
4121 - Diff Spacer
4123 -
Spring Washer
1 - I
NSTALL AND GREASE THE DIFF BALLS
Place the spur gear flat on the table in front of you with the side that says “CRC” facing
down. The diff balls will fall into each of the outer ring of holes in the diff gear, but won’t
fall out the other side. Place a small dab of silicone diff grease on each ball to lube the
ball and prevent the balls from falling back out of the holes during assembly. Use very
little!
*(Holding the car on it’s side, with the rear axle pointing upright will ease assembly of
the diff.) Place 1 diff ring, and then a 1/4” x 3/8” plain bearing over the end of the axle.
Align the diff ring so that it notches into the axle flange. Place the assembled gear with
the greased diff balls over the axle and push it down over the plain bearing. Next, insert
the other plain bearing into the back of the diff hub. Then, align the second diff ring with
the notch on the back of the diff hub. *(place a small dab of the diff grease on the hub
first to hold the ring in place.)* Now, slide the hub, bearing, & diff ring down over the
axle. Next, slide a flanged bearing over the axle and into the front of the diff hub.
2 - D
IFF
A
SSEMBLY
1
** Balls in outer ring of holes in gear **
1386 - 1/4” x 3/8”
Flanged Bearing
D
IFF
A
SSEMBLY
-
CONTINUED
...
The diff spacer has a small machined lip on one
side, point that lip toward the bearing. Now,
place the spring washer so that the cone points
away from the gear. The outside of the washer
should be against the diff spacer, and the inside
of the washer should be against the diff nut,
which now goes on last. *Be sure the 2 “D” rings
have settled into their notches. Just snug the nut
so the parts stay together on the diff axle.
DON’T over-tighten so the outer diff hub bearing
gets crushed! Correct diff tension needs to be
set with tires on the car.
1533
9
3 - Setting the Diff
First, you will want to mount a rear wheel (not included) to the left rear clamp hub using 1 of the M4
nuts contained in Bag 11. Until you are happy with the diff tension, you can just slip the right rear
wheel over the hex without mounting it. Now adjust the diff nut so that the tires spin back and forth
freely when holding the spur gear, but it is very difficult to slip the spur gear with your thumb when
holding both tires. Again - DON’T over-tighten so the outer diff hub bearing gets crushed! Re-check
diff tension after the first run.
Bag 8
Differential Axle
Bag 9
Differential
4720 - Axle Spacer-
Xti-2 + 5mm
64172
64180
64188
64196
1528 - Graphite Axle
w/ 4mm Stud
1533 - Left Clamp Hub
1525 - Diff Hub
1228 - 3/32 Diff Balls
1376 - 4-40 x 3/8”
Steel Socket Cap
1528
2mm
1499 - M4
Locknut
Small lip
toward bearing
1525
1228
1526
4 - Mount the Right side
Wheel
First, insert the 2-56 set screw
into the pin drive cap. You need to
thread this in first because it will
not fit through the hole in the diff
hub. Next, insert the cap into the
hub and lock in place with the
drive pin. Now slip the .035 allen
wrench through the hole in the
hub to lightly snug the set screw.
This doesn’t need to be tight. It is
just so it doesn’t get lost when
you take the wheel off. The wheel
actually holds the pin.
1527
1597
1527 - 2x14 Drive Pin
1597 - 2-56 x 1/8 Set Screw
1526 - F1 Pin Drive Cap
