GILLIG LOW FLOOR, Service Manual

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6
Transmission/Driveline/Rear Axle
Probalyzer Sampling System
The optional Probalyzer™ brass mini-gauge sampling valve allows for easy transmission fluid sampling
without shutting down the unit.
Sampling with the Probalyzer plug requires the compatible Probalyzer I cap, which screws onto standard
4-ounce sample bottles, or the Probalyzer II Bottle, which is a self-contained sampling bottle.
Probalyzer mini-gauge plugs carry a lifetime guarantee. Consult your Gillig Service representative for
more information, or call Titan Laboratories at (800) 848-4826. Titan Laboratories also offers analysis
services. Dust cap replacements are all available through your Gillig Parts representative.
Checking Transmission Fluid Level
Do not allow dirt or foreign matter to enter the filler tube when checking
fluid level or adding fluid to the transmission. Before removing the
dipstick, clean around the end of the filler tube.
A Davco transmission flu id-level gauge, located on the rear-run box, indicates readings from Davco’s
“Electronic Dipstick.” This makes it possible to check the fluid level without using the manual dipstick.
See “Davco Transmission Fluid Level Gauge” later in this section for information on using this gauge.
To check transmission fluid manually, read the following:
Perform a cold and hot check daily to ensure that the proper level is maintained. Carefully follow the
procedures in the “Cold Level Fluid Check” and “Hot Level Fluid Check” sections which follow before
checking the fluid level of the transmission. Always check the fluid level at least twice for each cold and
hot check to ensure that an accurate dipstick reading is obtained. If inconsistent readings occur, check
for proper venting of the transmission breather.
High or low fluid levels can result in poor performance and irregular fluid temperatures. A high fluid lev -
el will cause the planetary gear units and clutches to be partially immersed in the sump fluid. Rotation of
the clutches and gears inside the transmission churn the fluid causing it to become aerated. The aerated
fluid will cause overheating and irregular shift patterns. A low fluid level results in an insufficient supply
of fluid to the converter and clutches, which can cause overheating and potential transmission damage.
Transmission input speed and fluid temperature affect the fluid level. An increase in input speed lowers
the fluid level; an increase in fluid temperature raises the fluid level. The fluid level should be checked
with the engine at idle and the transmission in neutral. A cold fluid level check should be taken to ensure
there is enough fluid in the transmission to operate the vehicle until normal operating temperature is
reached. A hot (normal) check should be taken when the transmission fluid reaches a normal operating
sump temperature to ensure the fluid is at the proper operating level. When checking hot and cold fluid
levels observe the hot run and cold run sections of the dipstick respectively. Following are the tempera-
ture ranges for hot and cold checks:
Hot Check: 160–200° F (71–93° C)
Cold Check: 60–120° F (16–49° C)