The gaskets have arrived from Blighty so a quick departure to the garage after dinner saw the ball housing installed… with all the recommended components.. read on!

Mating surface wiped down with acetone


All the gaskets will be backed up with some Loctite sealant. This actually has a Land Rover part number for post 2012 Defenders so it’s used to keep fluid in somewhere on more modern machines.


A generous bead is applied…


… new gasket loosely pushed into the sticky goop


More sealant is applied to the bell housing face and things are almost ready to be bolted back together.

Whist reading the workshop manual on how to refit the bellhousing, I was somewhat flummoxed by the instruction to, “refit the main-shaft roller bearing”! Eh?

I’d stored the parts I’d taken off the gearbox in sequential order and there was no roller bearing amongst them. What did I miss? Did it fall out on the floor. I checked under the workbench and surrounding cobwebby nooks and crannies… no roller bearing. I could only conclude I’d rebuilt the gearbox without this bearing inside… which would account for the situation I was now in.

This was confirmed when I went through my spares shelf and found a brand new roller bearing still in its box!

I wasn’t sure if this was a “eureka” moment… or a, “I don’t f#cking believe it” moment! I went with the latter as I kicked the cat round the garage.

Assuming I’d have fitted the bearing, the nose of the main shaft would be supported correctly inside the primary pinion and the shaft would always run true.

With the bearing missing, it leaves a gap and the nose of the shaft is rotating in free space… and under acceleration, it would not run true. The only thing keeping it running true was the outside of the synchromesh. The inner part of the synchromesh on the main shaft would always be compensating for the missing bearing. Therefore, under regular / constant fatigue, the springs snapped and the synchromesh failed.

I had noticed periodically, a vibration under hard acceptation in 3rd gear…. it’s not unheard of for this to happen but the missing bearing would account for this.

Longitudinal section through the gearbox

Lets get back to fitting it all back together… with all the required components…

Let me introduce you to the Mainshaft Roller Bearing!


Constant gear balanced on the end of the layshaft. This gear needs to be partially engaged on the shaft when the gear on the primary pinion mates with it. Then the mainshaft (and bearing) needs to fit with the inside of the primarily pinion. A bit of judicious wiggling things about sorts this out.


Primary pinion, constant gear (and spacer) being pushed home.


Ta Da 🙂


The 4 large fixings (3 bolts and one stud) and tightened down


Next, the caslteated nut, washer and (new) split pin are fitted to the layshaft. (the vapour from the acetone used to clean the gasket surface had gone to my head)


The gearbox needs to be in gear to tighten the nut and the hand brake assembly on the back needs to be locked on hard. (which is was) This prevents the whole gearbox rotating when the nut it tightened.


Layshaft sans nut


The nut has to be tightened to 10m/kgs of torque plus however much additional rotation required to line up one of the gaps in the nut with the hole in the shaft.


Torque wrench is deployed


Once tighten down and aligned, the split pin can be dropped through the gap and turned back on itself.



*No cats were harmed in the making of this feature.