Converter Lock-Up Control
Installation Instructions
Converter Lock-Up Control
TH700-R4/4L60, 200C, 200-4R, 350C
Part Number 70244
© 2008, 2007 & 2001 by B&M Racing and Performance Products
NOTE: This kit is designed for transmissions equipped with a mechanically driven
speedometer cable. Use kit P/N 70248
with transmissions equipped with electronic speed sensor.
Please read the instruction sheet thoroughly before attempting to install your
B&M Converter Lock-Up Control.
B&M’s Converter Lock-Up Control
provides driver control of the speed where
converter clutch lock-up takes place.
This dash mounted electronic control
module has a dial to adjust lock-up
speed, a two color LED (Light Emitting
Diode) that indicates the lock-up clutch
status and a power on/off button. The
Converter Lock-Up Control module
receives a signal from the supplied speedometer cable mounted sensor. This signal along with the dial setting determines
the precise speed at which to activate
the lock-up clutch solenoid. Whenever
the ignition is on and power button is
engaged but the vehicle is stopped or
moving slowly the LED is RED (lock-up
clutch off). When the vehicle reaches the
speed preset by the dial on the Converter Lock-Up Control module, the
LED turns GREEN and power is available
to the lock-up clutch solenoid. This will
Printed in the U.S.A.
activate the solenoid and cause the converter clutch to lock-up. Once the transmission has shifted beyond first gear and
the solenoid is activated, lock-up will occur
at any speed within the range of the LockUp Control. B&M’s Converter Lock-Up
Control will not cure a defective converter
clutch, however if the clutch is not defective
the B&M Converter Lock-Up Control will
lock it at the preset speed.
WARNING: When using B&M’s Converter Lock-Up Control with any four
speed overdrive transmission, we recommend that lock-up speed not be set
higher than 45 MPH. Operation in fourth
gear (Overdrive) without the converter
clutch locked-up can result in transmission and engine overheating.
speed limit. Verify proper operation of
lock-up clutch and transmission. Accelerate the vehicle at low speed until it
shifts into third gear. Lock-up clutch
operation (in stock vehicles) can usually
be checked by operating the vehicle at a
steady speed and lightly depressing the
brake pedal just enough to activate the
brake light switch. Alternatively, depress
the throttle a small amount but rapidly,
this should cause the lock-up clutch to
disengage, then rapidly return throttle to
steady speed position and lock-up clutch
should reengage. Whenthelock-upclutch
engages and disengages you should notice a 200-500 RPM change in engine
speed. If the lock-up clutch is defective
replace the torque converter.
Before installing your B&M Converter
Lock-Up Control we recommend that
you perform a few simple transmission
performance checks and make sure you
have certain tools and equipment on
hand to assist in the installation.
Check overall transmission performance
for shift quality and timing. If performance
seems sluggish or shift timing is occurring too early or late check vacuum lines
and transmission throttle valve or detent
cable adjustment. Check transmission
oil pressures and compare them to the
appropriate service manual for your vehicle. If the problems persist B&M has a
complete line of products for rebuilding
and enhancing the performance of
General Motors Transmissions.
Operate vehicle with range selector in
third gear (Drive) position. Choose an
area where you will not exceed the local
Not legal for sale or use on pollution controlled motor vehicles.
Slide switch in
this direction
TCC & Brake
light switch
Ring terminal
Switched 12 volts
Chassis ground
Red (thin)
8 Pulse/Rev.
Speedometer cable
mounted speed sensor
Black (thin)
Figure 1
Installation of B&M’s Converter LockUp Control requires clear access to
the underside of the vehicle in order to
properly route wires and install speed
sensor. Raise the vehicle so there is 2
feet or more ground clearance.
The B&M Converter Lock-Up Control is relatively simple to hook up.
There are five wires connected to the
Converter Lock-Up Control module
which are color coded and have the
following functions:
+12V, 5A-10A fused,
ignition key controlled
Chassis ground.
Supplies +12V to
transmission lock-up
clutch solenoid.
Red (thin) Speed sensor.
Black (thin) Speed sensor.
Installation of the B&M Converter LockUp Control requires hooking up only the
Red, Black and Yellow wires, the Black
(thin) and Red (thin) wires are already
connected to the speed sensor unit.
STEP 1. Choose an accessible location on the dash to mount the Converter Lock-Up Control module. Using rubbing alcohol, clean the surface.
Remove the backing from the hook &
loop tapes and install on the Converter Lock-Up Control module &
STEP 2. Locate ignition key controlled
5A-10A fused source of +12V and a
good chassis ground connection. Most
GM fuse panels have an instrument
section that can be tapped to supply
the Converter Lock-Up Control module. Use a VOM (Volt-Ohm Meter) or a
test light to check the continuity and
voltage between the proposed power
source and ground.
STEP 3. Connect the Red wire to +12V
power source and the Black wire to
ground connection located in STEP 2.
Reversing the polarity of these two wires
will damage the Converter Lock-Up
Control module and VOID THE WARRANTY. Route wires so they cannot
become tangled in any mechanisms
(brake pedals, A\C, heater controls).
STEP 4. Route remaining wires from
the Converter Lock-Up Control module to the transmission. Make sure
wires passing through the fire wall or
floor pan are adequately protected
against abrasion with the sheet metal.
Also take care not to route wires near
hot exhaust pipes and high tension
ignition wires. The heat will melt insulation from wires and the ignition pulses
can cause unpredictable Converter
Lock-Up Control operation.
STEP 5. Disconnect the speedometer
cable at the transmission end. Install
the short adapter cable supplied with
kit on the transmission making sure
cable core is engaged in transmission
fitting. Next install the speed sensor
and connect speedometer cable to the
other side. Rotate sensor so that wires
do not hang down and are out of the
way of any moving mechanism or hot
STEP 6. For most applications connect the Yellow wire as shown in
Figure 1 which shows the proper wiring hookup for the Converter Lock-Up
Control. This diagram shows the stock
TCC (Torque Converter Clutch) and
brake light switch with the yellow wire
feeding through the switch and continuing down to the ‘A’ terminal on the
connector going into the transmission.
For ease of convenience, the kit is
supplied with the yellow wire and a
black grounding wire attached to a
connector that will plug directly into the
transmission. This yellow wire can be
cut and routed to the brake light switch
and then continue to the Converter
Lock Up Control. The short black wire
can be attached to a transmission pan
bolt to ground the circuit. In custom
applications you can bypass the brake
light switch, and you can plug the
supplied transmission connector directly into the transmission and ground
the short Black wire from pin D. We
recommend that you wire the Con-
ECU controlled TCC
have these
NOTE: TCC valve train and bore are not
present beginning 1989 model year
Remove spring if
TH-700-R4 valve body TCC valve train
Figure 2
verter Lock-Up Control through the
brake switch as a safety precaution.
The brake switch disengages the lockup clutch upon brake application in the
unlikely event of an electrical malfunction. Route wires next to members
where they can be secured. Once again
remember to avoid mechanisms and
hot pipes which can fray or melt the
insulation and cause a short circuit.
Operation of your B&M Converter LockUp Control is automatic once it has
been preset to the desired lock-up speed.
When properly connected the Red LED
on the front of the Converter Lock-Up
Control should light when the ignition
key is turned on (if it does not, please
recheck the Red & Black wires). Lockup engagement speed is adjusted while
operating the vehicle. Operate the vehicle at the speed where you want the
lock-up to be engaged continuously.
Turn the knob until the Green LED lights
and the converter clutch lock-up occurs.
The lock-up engagement speed can be
changed at any time to suit driving conditions by turning the knob left or right as
B&M’s Converter Lock-Up Control is
especially suited for controlling the lockup clutch in vehicles with custom transmission installations which were not
originally manufactured with a torque
converter clutch equipped transmission.
Custom transmission installations utilizing early model transmissions with
valve body controlled lock-up (TH-2004R, TH-700-R4) speed may require
some modification to operate correctly.
In these cases consult the appropriate
factory service manual to locate the
converter clutch shift valve train in the
valve body. Deactivate the converter
clutch shift valve by removing the spring
holding the valve train in the OFF position. This will allow the converter clutch
shift valve to move to the ON position
and ensure that control pressure is
always available at the converter clutch
apply valve after the first gear shift. A
TH-700 converter clutch shift valve train
is shown in Figure 2 as an example.
It may also be necessary to remove the
oil pan and identify which kind of solenoid
and wiring scheme is used on your
particular unit. A prewired four pin transmission connector (attached to the Converter Lock-Up Control module) is provided for these applications.
The lock-up clutch is located inside the
torque converter and is designed to
eliminate torque converter slip for improved efficiency. In GM vehicle’s the
speed at which lock-up clutch engagement occurs is controlled either by
hydraulic circuits inside the transmission or by the vehicles Electronic Control Unit (ECU). Lock-up clutch engagement occurs when the Converter
Clutch Apply Valve changes position
and vents the area behind the lock-up
clutch piston. The converter clutch apply valve’s position (on/off) is determined by the converter clutch solenoid
and the availability of control pressure.
In most early applications the solenoid
is always energized and control pressure is supplied by a shift valve in the
valve body which determined at what
speed lock-up occurred. Later applications eliminated the shift valve altogether and supply control pressure
TCC & brake
+12 V
TCC solenoid
Figure 3
4th gear pulse
TCC & brake
TCC solenoid
4th gear switch
Vacuum valve
throttle switch
TCC applies in
2nd, 3rd or 4th
gear under ECU
EGR solenoid
TCC solenoid
Governor switch N.O.
TCC applies in 3rd
gear only
TH-350- MV4,
TH-200C - MV9
3rd gear switch
MX2 only
TCC & brake
TCC solenoid
TCC applies in
3rd gear only under ECU control
TH-350C - MV4,
TH-250C - M31
TH-200C - MY9
3rd gear switch
MX2 only
Note: The above illustrations
for reference only. Your particular unit may not have all components shown.
electrical connector
pin identification
Figure 4
continuously. In the later units the
ECU is used to energize the solenoid
at the appropriate speed by providing
an external ground to the solenoid. In
all of the above cases control pressure
becomes available only after the transmission shifts out of first gear. Hence
the torque converter clutch will never
lock-up in first gear. The converter
clutch solenoid is located inside the
transmission, as are the converter
clutch apply valve and, if equipped,
Converter Clutch Shift Valve. Access
to these components requires oil pan
removal. Some applications may require inspection or modification of these
The lock-up solenoid is connected to
a four pin (some early units have two
pins) connector located on the transmission case. The pins on these connectors are identified by the letters A,
B, C and D.
Lock-up solenoids come with either
one or two wires. The one wire style is
internally grounded and requires only
a +12V connection to energize. One
wire solenoids are generally hooked
up to connector pin A, see Figure 3.
Two wire solenoids require both +12V
and ground connections to operate.
Two wire solenoids are usually hooked
up to pins A and D, where A is +12V
and D is ground, see Figure 4. Depending on the application one or both
of the solenoid wires may also be
connected to pressure switches on the
valve body either before, or instead of,
going to pin D. Reversing the polarity
on a two wire solenoid can damage an
internal diode which protects the electrical system from voltage spikes.
Besides the normal electrical repair
tools, i.e. wire cutters, stripper and
terminal crimper, a VOM (Volt Ohm
Meter, or at the very least a 12V test
light) is required to check voltage polarity and circuit continuity. Incorrect polarity connections or short circuits will
damage the Converter Lock-Up Control electronic module and void the
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