Nitro 2WD V6-4.0L (2007)
Gear ratios can be determined by using the scan tool and reading the Input/Output Speed Sensor values in the "Monitors" display. Gear ratio can be
obtained by dividing the Input Speed Sensor value by the Output Speed Sensor value.
For example, if the input shaft is rotating at 1000 rpm and the output shaft is rotating at 500 rpm, then the TCM can determine that the gear ratio is 2:1.
In direct drive (3rd gear), the gear ratio changes to 1:1. The gear ratio changes as clutches are applied and released. By monitoring the length of time it
takes for the gear ratio to change following a shift request, the TCM can determine the volume of fluid used to apply or release a friction element.
The volume of transmission fluid needed to apply the friction elements are continuously updated for adaptive controls. As friction material wears, the
volume of fluid need to apply the element increases.
Certain mechanical problems within the input clutch assembly (broken return springs, out of position snap rings, excessive clutch pack clearance,
improper assembly, etc.) can cause inadequate or out-of-range element volumes. Also, defective Input/Output Speed Sensors and wiring can cause these
conditions. The following chart identifies the appropriate clutch volumes and when they are monitored/updated:
SHIFT SCHEDULES
As mentioned earlier, the TCM has programming that allows it to select a variety of shift schedules. Shift schedule selection is dependent on the
following:
-
Shift lever position
-
Throttle position
-
Engine load
-
Fluid temperature
-
Software level
As driving conditions change, the TCM appropriately adjusts the shift schedule. Refer to the following table 42RLE Shift Schedule to determine the
appropriate operation expected, depending on driving conditions.
