This part of site is an attempt to organize and add to the web resources for the Rover SD1
to form a cohesive and easily usable guide for those of us without easy access to
expert repair and/or advice. It is not offered in any way as a definitive source
and we take no responsibility for any errors that may exist.
the webmaster Rene Winters.
Now the mainshaft, starting at the rear, remove the circlip from behind the centre
bearing and extract the bearing using a handpress, fitted with half moons 18G47-3
then slide the 1 st speed gear and flanged bush, the 1 st speed synchro-cup, the 1st/2nd
synchro-hub and sleeve, the 2nd speed synchro-cup and the 2nd speed gear from the shaft.
Note the 2nd speed synchro-cup is different from the other four. It has wider slipper
To remove the pilot bearing, position the mainshaft in the hand press, with 3rd gear
supported on half moons 18G47-1, and push out the mainshaft using a suitable sized
This will also release the spacer, the 3rd/4th synchro-hub and sleeve assembly and the
3rd speed synchro-cup and gear.
Before reassembling the box, each component must be cleaned and carefully examined,
including the mainshaft oilways.
These oil passages play an important role in the lubrication of the mainshaft components.
Clean the magnetic drain plug and fit a new fibre washer.
Check each gear for chipping and the gear and synchro-cup conical surfaces for wear.
Examine the five roller bearings and their external tracks. If a bearing is being replaced,
replace the track as well. Incidentally, on early boxes, the input shaft bearing was the
same size as the mainshaft centre bearing. On current boxes the input shaft bearing has
As with the mainshaft bearings, the input shaft bearing and layshaft bearing are
removed and replaced using a handpress fitted with the following half moons.
The layshaft bearings with LC370-2, the earlier input shaft bearing with 18G47-3 and the
larger, more recent, input shaft bearing with 18G47-5.5
The pilot bearing track is an interference fit in the input shaft and must only be removed
using 18G284 and 18G284AAH.
The new track is fitted using a hand press.
REASSEMBLING THE GEARBOX|
The Synchro-Hub Assemblies
Next the synchro-hub assemblies. Unlike the single rail box, the 77mm hubs are fitted with
slipper pads and circular springs.
When refitting the springs, fit the first spring in a clockwise direction, with its leg
inside a slipper pad. Turn the hub over and fit the second spring, again in a clockwise
direction, with its leg in the same slipper pad.
As you see, the 3rd/4th and the 5th speed synchro-sleeves are symmetrical and identical.
However if a sleeve and hub are separated, the sleeve must be refitted as found; so mark
The 3rd/4th hub is identified by the side relief of the splines. The flats machined at
the rear prevent 3rd gear jumping out.
The 1 st/2nd sleeve must be fitted with the reverse gear teeth adjacent to the shorter
splines on the hub.
The Mainshaft |
The inspection is complete, we can now rebuild the mainshaft. Start at the rear by fitting
the 2nd speed gear and its synchro-cup, the cup with the wider slipper slots then fit
the 1 st/2nd synchro-hub and sleeve assembly. The reverse gear teeth must be towards
the 2nd gear.
Fit the 1 st speed synchro-cup, the 1st speed gear and its flanged bush.