Hot Check - PREVOST H3-41 Maintenance Manual

SECTION 07: TRANSMISSION
The oil level rises as sump temperature
increases. DO NOT fill above the Cold Run
band if the transmission oil is below normal
operating temperature.
overfull transmission can become overheated,
leading to transmission damage.
1. Move the vehicle to a level surface, put
transmission in «N» (Neutral), and set the
parking brake.
2. With the engine idling (500 - 800 rpm), shift
to «D» (Drive) and then shift to «R» (Reverse)
to clear the hydraulic system of air.
3. Run the engine at idle in «N» (Neutral) for
about one minute.
4. While the engine is running, remove the
dipstick from the tube and wipe it clean
(Figure 4). Insert the dipstick into the fill tube,
pushing down until it stops.
5. Remove the dipstick and observe the fluid
level. Repeat the check procedure to verify
the reading. If the fluid on the dipstick is within
the COLD CHECK band, the level is
satisfactory for operating the transmission
until the oil is hot enough to perform a Hot
Check. If the fluid level is not within this
band, add or drain fluid as necessary to bring
the level within the COLD CHECK band.
6. Perform a Hot Check at the first opportunity
after the normal operating temperature of
160ºF to 200ºF (71ºC to 93ºC) is attained.
FIGURE 5: COLD CHECK
CAUTION
DO NOT operate the transmission for extended
periods of time until a Hot Check has verified
proper fluid level. Transmission damage can
result from extended operation at improper fluid
level conditions.
CAUTION
Obtain an accurate fluid level by imposing the
following conditions:
8
PA1621 Maintenance Manual All Series | January 2017
During operation, an
 Engine is idling (500-800 rpm) in «N»
(Neutral).
 Transmission fluid is at normal operating
temperature.
 The vehicle is on a level surface.

3.1.2 Hot Check

To perform a Hot Check, do the following:
1. The Hot Check can be performed when the
transmission oil
operating temperature (160ºF to 200ºF /
71ºC to 93ºC).
temperature can be checked with the Driver
Information Display (DID) when selecting the
Gauge menu (refer to the ''Operator's
Manual'' for added information).
CAUTION
The oil must be hot to obtain an accurate
check because the fluid level rises as
temperature increases.
2. Park the vehicle on a level surface and shift to
«N» (Neutral). Apply the parking brake and
allow the engine to idle (500 - 800 rpm).
3. Remove the dipstick from the tube and wipe it
clean. Insert the dipstick into the fill tube,
pushing down until it stops.
4. Remove the dipstick and observe the fluid
level. The safe operating level is anywhere
within the HOT RUN band on the dipstick.
Repeat the check procedure to verify the
reading.
5. If the level is not within this band, add or drain
fluid as necessary to bring the level within the
HOT RUN band.
6. Be sure fluid level checks are consistent.
Check level more than once and if readings
are not consistent, check to be sure the
transmission breather is clean and not
clogged. If readings are still not consistent,
contact your nearest
distributor.
FIGURE 6: HOT CHECK
NOTE
reaches the normal
The transmission oil
Allison dealer or