Mustang II Transmission Identification

RAD (Borg Warner) 4Speed Standard Transmission

The Model RAD four-speed transmission can be identified by the identification tag. This tag is located under the lower left side extension housing to transmission case retaining bolt.

Description:

The Model RAD four-speed transmission is of the fully sychronized type with all gears except the reverse gear being in constant mesh. All forward-speed changes are accomplished through forged blocker ring synchronized units.

The constant mesh gears, that is, the input shaft gear, the three other forward gears on the output shaft, and the corresponding gears on the countershaft gear, are helically cut. The reverse gear on the contershaft gear has straight-cut spur teeth which mesh, through an idler gear with spur teeth on the outside of the first-second gear synchronizer sleeve.

Gear selection is by means of a floor shift lever. The shift lever is attached directly to a single selector rail, which has the selector lever assembled to it, and is mounted in the transmission. Movement of the shift lever, and thereby the selector rail, causes the selector lever to locate in the appropriate selector fork and move it to the required position. Movement of the first-second or third-fourth selector fork causes the appropriate synchronizer sleeve to move as necessary to engage with the dog teeth on the required gear.

When reverse gear is required, movement of the reverse selector relay lever draws the reverse idle gear into mesh with both the reverse gear on the countershaft gear and on the output shaft.

Engagement of two gears at once is prevented by means of a selector interlock plate pivoted in the transmission cover. This plate engages with the selector forks that are not in use, and holds them positively in the disengaged position. The selector forks are not attached to the selector rail. The first-second and third-fourth forks, while they are mounted on the rail, are free to slide.

Gear Ratios

1974

1975

1976

1977

1978

Exploded view

Notes:
All data, images and descriptive text from Ford 1974-1978 Car Shop Manuals.
Editorial comments and layout are my own.
Due to mid-year production changes or errors in the manuals, it is likely there were combinations other than what is listed here.
Click on the exploded version of the transmission for a larger, more clear view.

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Lee Lafountain
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