Dodge RAM TRUCK 1500 1995 Service Manual page 1434

42RH/46RH/47KH TRANSMISSION IN-VEHICLE SERVICE 21-111
PRESSURE
LINE
RADIATOR
RETURN
RETURN
LINE
J9421-251
Fig. 28 Cooler Line identification (Gas Engine)
Cooler flow is tested by measuring the amount of
fluid pumped through the cooler in a specified time
by the transmission oil pump. The same flow test
procedure Is used for the drainback valve, main
cooler, and auxiliary cooler.
Cooler And Drainback Valve Flow Test Procedure
(1) Test flow through drainback valve as follows:
(a) Add extra quart of ATF Plus to transmission.
(b) Disconnect pressure line at radiator fitting, or
at drainback valve and position hose or valve end
in one quart test container.
(c) Shift transmission into neutral, run engine at
idle speed for 20 seconds, and note flow from valve.
Use stopwatch to check test time.
(d) Replace drainback valve if flow is less than
one quart in 20 seconds, is intermittent, or does
not flow at all.
(e) Connect pressure hose to radiator fitting and
proceed to cooler flow test.
(2) Test flow through main cooler as follows:
(a) Disconnect cooler return (rear) line at trans­
mission and place it in one quart test container,
(b). Add extra quart of fluid to transmission.
(c) Shift transmission into neutral, run engine at
idle speed for 20 seconds, and note flow from valve.
Use stopwatch to check test time.
(d) Replace cooler if fluid flow is less than one
quart in 20 seconds, is intermittent, or does not
flow at all.
(3) If vehicle is equipped with auxiliary cooler,
test cooler flow as described in step (2).
TRANSMISSION COOLER REVERSE FLUSHING
The flushing procedure applies to standard and
auxiliary coolers alike. Although pressure equipment
is preferred, reverse flushing can be performed with
hand operated equipment as follows.
(1) Identify and disconnect cooler pressure and re­
turn lines at transmission. Rear line is return line
from cooler. Front line is pressure line to cooler (Figs.
28 and 29).
(2) Position drain pan under cooler pressure line to
catch material flushed through cooler and lines.
(3) Reverse flush cooler using hand operated suc­
tion gun filled with mineral spirits. Insert gun nozzle
(or hose) into cooler return line. Then force mineral
spirits into line and through cooler.
(4) Continue reverse flushing until fluid exiting cooler
pressure line is clear and free from debris. Replace
cooler if fluid cannot be pumped through it.
(5) Clear flushing materials from cooler and lines
with short pulses of compressed air. Insert air gun
nozzle into cooler return line and continue short air
pulses until all fluid is cleared from cooler and lines.
(6) Pump one quart of fresh automatic transmis­
sion fluid through cooler and lines before reconnect­
ing lines.
TRANSMISSION COOLER REPLACEMENT
Main Cooler Replacement
The main transmission cooler is located in the ra­
diator lower tank. The cooler is not a serviceable
component. If the cooler is damaged in any way, the
radiator will have to be replaced.