Gearbox/OD Oil Change

The hollow drain plug from the roadster and some metal debris. As I recall the V8 drain plug was flat:

Roadster sump and gasket/filter, no damage to this on removal unlike the V8:

Sump and all the relief valve and filter components from the roadster. The V8 didn't have the coarse screen shown here, may have been left inside. I found all the shims between the valve plunger and the spring, increasing overall thickness sharpens/speeds-up engagement, reducing overall thickness softens/slows engagement. It's vital to get the valve plunger the right way round or OD will not engage:

From the original Leyland and Laycock Workshop Manuals. However whilst the 'low-pressure valve plug', 'valve spring' and 'valve ball' at the upper left are shown in both those and the Parts Catalogue and Haynes I didn't find them in either of my cars. Note that the selective shims are shown at the upper end of the spring, not the lower end as I found in both mine, but it makes no difference:

From the 77 and 78 Leyland manuals, without the 'low-pressure valve plug', 'valve spring' and 'valve ball', and with the shims below the spring. Also showing the coarse screen I found:

Subsequently information from Overdrive Repair Services in Sheffield is that the plug, spring and ball are pressed into the low-pressure valve body so would not normally be separately visible in routine servicing.

Yet another variation, a cylinder with cut-outs at one end, in place of my roadster coarse screen. Note that John Twist shows this type with the cut-out facing the hex plug, and not as here. It could make a difference if the oil has to flow back up the tube to escape from the slots rather than exiting directly, and is maybe why it was changed to the coarse screen I found which can be fitted either way up: Photo: Corky

Plastic squeezy bottle for gear and diff oil, with a flexible spout that just fits in the length of tubing, and the tubing just fits in the filler hole on both side and top fill gearboxes. The snug fit between spout and tubing means that even though the 'join' is horizontal when filling in the footwell no oil leaks out from it. But put plenty of cloths and paper down over your carpets just in case, I still spilt a little. This tubing is probably longer than it needs to be even for the side-fill gearbox:

Location of the access hole and bung AHH6507:

Loop of cord on the dipstick to aid removal:

The bung isn't pushed all the way in, just until the body panel slots into the groove (arrowed):

Note that the bung is still present on rubber bumper cars with the side-fill gearbox and some have said they use that hole to feed a tube through to the side fill for filling/topping-up. Others have said either that theirs doesn't have it, or the console is different and you can't access it, but not going by this 78: