NMC-WOLLARD 100 - Page 824

NMC-WOLLARD 2021Truax Blvd., Eau Claire, WI 54703, Phone (715) 835-3151, Fax (715) 835-6625
M100 Tow Tractor Manual No. 46052
DECEMBER 15, 2013
PAGE 168
CHAPTER 5 MANUFACTURER’S INFORMATION
GM 4L70 TRANSMISSION
© 2013 General Motors. All rights reserved
noted, inspect the transmission vent assembly to ensure it is clean and
unclogged.
4. Keep the dipstick tip pointing down and check both sides of the dipstick.
Read the lower level. Repeat the check procedure to verify the reading.
5. Inspect the color of the fluid on the dipstick. Refer to Fluid Condition
Inspection.
6. A safe operating fluid level is within the HOT crosshatch band on the
dipstick. If the fluid level is not within the HOT band, and the transmission
temperature is betwe
en 82–93°C (180–200°F), add or drain fluid as
necessary to bring the level into the HOT band. If the fluid level is low, add
only enough fluid to bring the level into the HOT band.
7. If the fluid level is low, add only enough fluid to bring the level into the
HOT band. It does not take much fluid, generally less than one pint (0.5L).
Do not overfill. Also, if the fluid level is low, inspect the transmission for
leaks. Refer to Fluid Leak Diagnosis.
8. If the fluid level is in the acceptable range, push the dipstick back
into the
dipstick tube all the way, and then flip the handle down to lock the dipstick
in place.
Fluid Condition Inspection
Inspect the fluid color. The fluid should be red or dark brown.
 If the fluid color is very dark or black and has a burnt odor, inspect the fluid
and inside of the bottom pan for excessive metal particles or other debris.
A small amount of “friction” material in the bottom pan is a “normal”
condition. If large pieces and/or metal particles are noted in the fluid or
bottom pan, flush the oil cooler and cooler lines and o
verhaul the
transmission. If there are no signs of transmission internal damage noted,
replace the fluid filter assembly, repair the oil cooler, and flush the cooler
lines.
 Fluid that is cloudy or milky or appears to be contaminated with water
indicates engine coolant or water contamination.