RING-AND-PINION UPGRADES
Whenever you’re doing axle servicing,
even if it’s just a simple bearing job
like this, you might want to consider
inspecting the ring-and-pinion gear and
possibly replacing it. For the average
enthusiast, replacing the ring-andpinion is best left to the pros because it
requires special tools; besides a driver kit
to install the bearing on the pinion gear,
you’ll need a special Ford service tool to
check the depth of the pinion, as well as
a dial indicator to measure backlash. This
must be precise to ensure smooth, quiet
operation of the gears and is adjusted with
shims to achieve the required clearance. If
you hear a whining from the rearend and
it’s not the bearings, chances are it’s the
result of sloppy gear installation, in which
the backlash is too tight.
If you’re planning on changing the rear
axle ratio, you’ll also need to change the
speedometer drive gear and also the driven
gears housed inside the transmission. On
cars equipped with manual gearboxes,
you can access the driven gears by pulling
off the tail shaft. On automatics, it’s not
so easy. Because the speedometer driven
gear is machined with the output shaft,
the transmission needs to be removed and
pulled apart to access the gear. On five-
speed cars, the nylon speedo gears tend
to wear out; if you see your speedometer
bouncing up and down, chances are the
gear is worn. Replacement speedometer
gears are available through Ford dealers
and are designated by different colors
and number of teeth different axle ratios.
You’ll need to match the axle ratio to the
correct speedometer gear to ensure an
accurate reading.
AXLE RATIOS
The reason for considering a
steeper axle ratio is to improve torque
multiplication, enabling the engine to
reach peak output more quickly. Even
with a stock engine, changing from 2.73:1
to 3.55:1 will notably improve off-theline acceleration. However, th