Manual Transmission

Manual Transmission

The S6-650 and the M6HD transmissions are 6-speed synchronized units. The ZF 6-speed has these features:
^ An integral clutch housing
^ An aluminum main case, extension housing and intermediate housing

The mainshaft has 2 tapered roller bearings.

Mainshaft end play is controlled by a selective shim located under the bearing cup countershaft has 2 tapered roller bearings. countershaft end play is controlled by a selective shim located under the bearing cup The countershaft is serviced as an assembly Synchronized in all gears All gears are helical All gears, including reverse, turn on needle roller bearings Single-piece shift forks with moly-coated pads Internal oil pump, driven by the countershaft, to supply transmission fluid to an external cooler Provisions for mounting a power take-off unit A reverse idler gear that does not need to be removed during disassembly The mainshaft and countershaft are assembled under preload. If the ZF transmission is disassembled, a preload measurement must be taken

The S6-650 and the M6HD have 6 forward speeds that feature a LOW gear for take-off under heavy loads and a OVERDRIVE gear for highway driving conditions. The gear ratios are as follows:
^ Low 5.79:1
^ 1st 3.30:1
^ 2nd 2.10:1
^ 3rd 1.31:1
^ 4th 1.00: 1
^ Overdrive or 5th 0.72:1
^ Reverse 5.23:1

Transmission Identification
All ZF transmissions are identified by the model and serial number. This information is on the transmission identification tag and affixed to the transmission case. Do not remove or destroy the transmission identification tag.