Interpretation ID: nht80-3.41

DATE: 08/29/80

FROM: F. BERNDT -- NHTSA; SIGNATURE BY STEPHEN P. WOOD

TO: Borg-Warner Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your July 29, 1980, letter asking whether Standard No. 102, Transmission Shift Lever Sequence, Starter Interlock, and Transmission Braking Effect, would prohibit the use of a free-wheeling device.

Section S3.1.2 of that standard states that "[in] vehicles having more than one forward transmission gear ratio, one forward drive position shall provide a greater degree of engine braking than the highest speed transmission ratio at vehicle speeds below 25 miles per hour." The purpose of this section is to provide a transmission braking effect as a supplemental braking system at speeds below 25 miles per hour. According to our understanding of your device, it may not provide the type of supplemental braking described in this paragraph. However, if the driver may activate some type of device to override the "free wheeling" aspect to provide some engine braking, then the requirement of Section S3.1.2 could be met.

SINCERELY,

Borg-Warner Corporation

July 29, 1980

Office of Chief Counsel National Highway Traffic Safety Administration

Re: Request for Opinion

Dear Sir:

We are interested in determining whether the provision of a free-wheeling device (such as a one-way clutch) in series with the drive train of a vehicle would violate any Federal Motor Vehicle Safety Standard, or any other law or statute.

Our engineers have proposed incorporating a one-way clutch in series with the prop shaft of a vehicle. The only standard which we found that appears related to this is No. 102, and particularly S3.1.2 "Transmission Braking Effect". We do not believe this would rule out incorporation of a free-wheeling device, as the driver could easily place the shift lever in neutral and preclude engine braking whether the transmission is manual or automatic.

Thank you in advance for considering this matter and providing us with your opinion.

James J. Jennings Assistant Patent Counsel BORG-WARNER CORPORATION