Gearbox

1948 to 1953 Land Rover gearbox and transfer box changes

Michael Bishop: The design behind the gearbox of the Land Rover was taken straight from the Rover cars of the day. One of the more elaborate parts of the earliest Land Rovers is the transfer box. The earliest vehicles used a Rover car freewheel in the front output to power the front differential. This makes them constant four wheel drive. This works much like a bicycle ratchet in that it the freewheel not only supplies power but also allows for the front wheels to override that power when they start changing speed in relation to the rear wheels when going around a corner. A lock is provided for locking the freewheel when four wheel drive is needed in reverse. On a hard surface reversing and turning causes serious gearbox windup as the freewheel doesn't do its job in reverse which resulted in it being dropped from the specification on the 1951 model.

861989	The front out put on the transfer box is made up out of two separate casings. The inner casing is the housing for the freewheel unit. The outer casing is the remains of a pre production two wheel drive/ four wheel drive selector which meant that the Land Rover could have had road going two wheel drive, Road going four wheel drive and locked four wheel drive in high or low ratio. This system was simplified to be constant four wheel drive in all forward gears with the key ring operating a lock on the freewheel for four wheel drive in reverse on low ratio only. On the first 1988 gearbox's the outer casing on the front output inside still had the dog to operate the selectable two/four wheel drive but with a spacer to stop it being selectable. These parts were removed from the gear box 861989 onwards and a complete front output shaft fitted from the freewheel. The ring pull for four wheel drive in reverse changed at gearbox No. 06104015. See also the changes at gearbox No. 16102314 and 16131688.
862381	The plate on the top of the transfer case with the oil filler plug is now held with four 1/4 Whit x 3/4" bolts instead of four screws
06100201	The clutch withdrawal mechanism changed so it can operate the Borg and Beck clutch. See the change at Engine No. 06100201
06104015	The 'Ring Pull' operrating lever for the freewheel lock for four wheel drive in reverse is changed to be a push down lever with a yellow knob for locking the freewheel in reverse. See also the change at chassis No. 06103885, on the basic model, at chassis No. 06200094, on the station wagon and at chassis No. 06300022 on the welder model.
06106001	Third gear changed from being the ratio 1.490:1 to being the ratio 1.377:1. It The drive for the speedometer changed from being type the bronze slot in type fitting to being held with three small bolt type of speedometer cable fitting. See also the change at chassis No. 06105831, on the basic model, at chassis No. 06200141, on the station wagon and at chassis No. 06300031 on the welder model.
06106829	Primary pinion and constant gear changed to suit a new clutch withdrawal mechanism. The operating shaft on the mechanism changed from having corse splines to having fine spines. The oil retaining parts for the clutch changed in side the withdrawal mechanism. The Primary pinion and constant gear changed in that out put has a small section of thread to keep the oil from weeping out along the shaft.
16102314 16131688	The transfer box has been completely changed to being the selectable two/ four wheel drive from the constant four wheel drive freewheel gearbox. See the parts book for the full details of the changes. Basically the gears remained the same and the front out put changed from the freewheel to the two/four selector. The housing for the speedometer drive changed to suit the new transfer box. See also Basic models, 16100603, 16160909, 16660787, 16131573 and 16630025, Station wagons No.'s 16200001, 16260021 and 16230081 and welders No.'s 16300003, 16360007 and 16330002.
16102393 16131730	The shield for the primary pinion, part No. 01017 is now fitted before the locking washer on the pinion shaft.
26100201	The bell housing on the front of the gearbox changed do with a change in the grommet that cover the right hand drive clutch operating shaft hole
26101202 26130387	The cover for the seal on the front output shaft flange from the transfer box changed from being a dust shield, part No. 232669 to being a mud shield, part No. 236074.
26100908 26130287	The gearbox mounting arms changed so that the hole for the top rubber is now a bolt on part held by two nuts instead of being the type which were all welded together.
26101454 26130447	The rear transfer case oil seal now has a mud shield, part No. 236074 added to it in behind the hand brake drum.
26110020 26137678	The bronze distance sleeve for the mainshaft between second and third gear is changed to be thicker an try to stop premature failure. Second and third gears were narrowed to be able to accomodate the wider distance piece.