B&M 20260 SHIFT IMPROVER KIT - Manual (Page 3)

Detent spring
Manual
linkage
Governor
tubes
Manual
valve
Vacuum modulator
Detent solenoid
Figure 5
Governor tubes
When removing valve body be sure not to allow
manual valve to fall out and be damaged
Figure 6
3
performance, depending on the vehicles
intended use:
1. Heavy Duty; Towing, campers, mo-
tor homes and 4-wheel drive vehicles.
Heavy Duty level is a good starting
place for light weight, high powered
vehicles such as street rods. Heavy
duty level produces firm noticeable
shifts.
2. Street; Dual purpose performance
vehicles, street and strip performance
cars and, off road vehicles. Street level
produces very firm, positive shifts.
DISASSEMBLY
Automatic transmissions operate
at temperatures between 180°F and
240°F. We recommend that the vehicle
be allowed to cool for several hours
before attempting disassembly to avoid
serious burns from hot oil and parts.
The vehicle should be raised so there is
at least 2 feet ground clearance for
ease of installation and safety.
MAKE SURE THE VEHICLE IS RIG-
IDLY AND SECURELY SUPPORTED,
JACK STANDS, WHEEL RAMPS OR
A HOIST WORK BEST. DO NOT USE
JACKS ALONE.
STEP 1. Have an oil drain pan ready to
catch oil and a clean tray on which to
put small parts so they won’t get lost or
dirty. Drain the oil by removing the rear
pan bolts and work towards the front
leaving the two front bolts in place. If the
pan is stuck to the case pry the pan
loose with a screw driver. Slowly re-
move the remaining two front bolts al-
lowing the rest of the fluid to drain.
STEP 2. Oil filter removal. Two types of
filters have been used on the TH-400:
Figure 3. 1964-67: This filter is a long
box-like unit that runs along the drivers
side of the case. Remove by grasping
both ends of filter and pulling it straight
down. Watch out for oil splatter. Re-
move the O-ring from the bore in the
case if it did not come out with the filter
oil pick-up tube. Be careful not to scratch
the case bore when removing the O-
ring.
Figure 4. 1968 and later: This filter is a
large flat unit held to the transmission
with a shoulder bolt. Remove the shoul-
der bolt and pull filter straight down.
Some models also use a spacer be-
tween the filter and valve body. Watch
out for oil splatter. If the oil pick-up tube
did not come out with the filter, pull it
out. Remove the O-ring from the bore in
the case if it did not come out with the
oil pick-up tube. Be careful not to scratch
the case bore when removing the O-
ring.
STEP 3. Observe the location of the
following (See Fig. 5) Manual linkage,
detent spring with roller and the way
linkage engages the manual valve in the
valve body, governor tubes and their routing, detent solenoid (oval or square
can) and its wire connector, white smog
switch wire (’71 and later) and routing of
the wire.
STEP 4. There are (3) 1/4-20 and (8) 5/
16-18 (10 some early models) bolts
holding the valve body. Remove all but
one valve body bolt and disconnect the
switch wire if present. Hold the valve
body in place and remove the last bolt.
Lower the valve body while at the same
White smog
switch wire
(1971 and later)
Manual
linkage
pin