---
kind: "section"
citation: "40 C.F.R. § 1037.232"
title: "40"
number: "1037.232"
heading: "Axle and transmission families."
url: "https://uscodex.org/cfr/40/1037.232"
---

# §1037.232. Axle and transmission families.

- (a) If you choose to perform axle testing as specified in [§ 1037.560](/cfr/40/1037.560.md) or transmission testing as specified in [§ 1037.565](/cfr/40/1037.565.md), use good engineering judgment to divide your product line into axle or transmission families that are expected to have similar hardware, noting that efficiencies can differ across the members of a family. Note that, while there is no certification for axle and transmission families under this part, vehicle manufacturers may rely on axle and transmission test data to certify their vehicles.
- (b) Except as specified in [paragraph (d)](#d) of this section, group axles in the same axle family if they have the same number of drive axles and the same load rating.
- (c) Except as specified in [paragraph (d)](#d) of this section, group transmissions in the same transmission family if they share all the following attributes:
  - (1) **Number and type of clutches (wet or dry).**
  - (2) **Presence and location of a fluid coupling such as a torque converter.**
  - (3) **Gear configuration, as follows—**
    - (i) Planetary (e.g., simple, compound, meshed-planet, stepped-planet, multi-stage).
    - (ii) Countershaft (e.g., single, double, triple).
    - (iii) Continuously variable (e.g., pulley, magnetic, toroidal). Note that GEM does not accommodate efficiency testing for continuously variable transmissions.
  - (4) **Transmission oil sump configuration (conventional or dry).**
- (d) You may subdivide a group of axles or powertrains with shared attributes under paragraph [(b)](#b) or [(c)](#c) of this section into different families.

## Notes

### Authority

Authority: 42 U.S.C. 7401—7671q.

### Source

Source: 81 FR 74048, Oct. 25, 2016, unless otherwise noted.