What it is
The 4L60E has a dedicated 3-2 control solenoid that manages how quickly the transmission releases and applies clutches during a downshift from third to second. Get it wrong and that downshift flares (the revs jump before second grabs) or it thumps in hard. The 3-2 Control Duty Cycle table is only shown in NSP when the Transmission Type in transmission control is set to GM 4L60E, because no other supported transmission has this solenoid.
When the table is used
Most of the time the Nexus runs the solenoid at fixed values, just as the factory controller did:
| Situation | 3-2 solenoid duty |
|---|---|
| In 1st gear | 0%, fixed |
| In any other gear | 90%, fixed |
| During a 3rd to 2nd downshift | Taken from the 3-2 Control Duty Cycle table |
So the table only matters during that one shift. You can't change the fixed values, only the downshift behavior.
Our advice
Don't build this table from scratch. Import it from a supplied 4L60E base map, which gives you values that suit the factory hydraulics. Only change it if a 3-2 downshift is clearly flaring or harsh, change it in small steps, and log gear, RPM and the solenoid duty so you can see what changed. If the transmission has a modified valve body, expect to revisit it.
Related Nexus transmission pages: transmission control wiring, shift duration and auto mode shift points. For a GM four-speed auto, the Nexus Ti4L transmission interface kit is worth a look.
