# Transmission

**Libraries:**

Simscape /
Driveline /
Gears

## Description

The Transmission block represents an abstract transmission
for system-level driveline models. The block accepts the gear ratio command as a
physical signal to port **G**, where `0`

represents
neutral, `-1`

represents reverse, and the values in the
**Forward gear ratios** parameter represent the forward gears. The
length of this vector corresponds to the number of forward gears. The block rounds the
input values to integers. The transmission is non-sequential, which allows you to
transition between any two gear ratios without having to stop at the intermediate
ratios. For the block to behave like a sequential transmission, you must specify each
gear ratio in the sequence.

The Transmission block is a composite of two blocks. The block uses a subcomponent implementation of the Variable Ratio Transmission block to simulate the transmission gear ratio dynamics, and the block simulates abstracted clutch dynamics using the Logic-Controlled Clutch block. To learn more, see About Composite Components.

### Thermal Model

You can model the effects of heat flow and
temperature change by enabling the optional thermal port. To enable the port, set
**Thermal port** to `Model`

.

## Ports

### Input

### Conserving

## Parameters

## Extended Capabilities

## Version History

**Introduced in R2022a**