Lotus 2004 Eleven Service Notes page 209

Lotus Service Notes
The two shaft, all indirect gearbox, is housed within a two or three part cast alloy casing, including the dry
chamber clutch housing, and secured by threaded fasteners to the back of the engine block. The clutch friction
plate is splined to the gearbox input shaft from which the power flows to the output shaft mounted below it, and
thence to the final drive and differential into which are fitted the driveshafts.
In the C56 5-speed gearbox, ratios 1 to 4 including reverse, are contained within the main case, with the
5th gearset overhung at the rear within an end cover. The input shaft uses a front roller bearing and a rear
ball bearing, as does the output shaft, albeit with a much larger front roller to accommodate the final drive gear
forces. Needle roller bearings are used for each of the free spinning gears, and a pair of taper roller bearings
support the differential assembly. Sychroniser assemblies for 3rd/4th and 5th speeds are mounted on the in-
put shaft, and that for 1st/2nd on the output shaft, with the latter also providing the reverse gear driven pinion
incorporated on its periphery. A reverse gear idler pinion is mounted on its own stub shaft, and may be slid into
engagement with both a gear integral with the input shaft, and the ring gear on the 1st/2nd synchroniser. The
housing for the final drive and differential is shared between the clutch housing and gearbox case, with taper
roller bearings supporting the differential.
The C64 six-speed transmission is a development of the C56, with both shafts extended at the rear to
accommodate the additional ratio. Extra ball bearings are included in the end case to support the tails of each
shaft.
The EC60 6-speed transmission is a further evolution of the C64, but dispenses with the separate end
casing and shaft centre support bearings, using instead, front and rear ball bearings for the input shaft, and
a pair of opposed taper roller bearings for the output shaft. A reverse gear engagement aid is provided by a
mechanism which applies a loading to the 6th gear synchroniser cone, to help stop input shaft rotation, before
the reverse idler gear teeth are slid into engagement.
Section FJ
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