NORFOLK GARAGE

decided to tackle the clonk first. A short test drive revealed that there were two separate sources of the noise: somewhere at the back, and a much fainter noise in the vicinity of the transmission.

The noise at the back was easy enough to diagnose – the rubber boot on the A frame ball joint had fallen to bits, allowing water and grit to get inside the joint Changing these joints is not one of my favourite jobs. The ball joint is pressed very firmly into a cast steel carrier, and the two are almost inevitably rusted solidly together. I have a 20 tonne hydraulic press in the workshop, but it is well overdue a rebuild so I did not hold out much hope of being able to separate the ball joint from the carrier. New carriers are available but they are not especially cheap. To my absolute astonishment the joint started to move with only a couple of strokes of the pump handle, and in no time at all the assembly was back on the vehicle with some new bolts, Nyloc nuts and plenty of copper grease to help whoever has to change the joint next time.

Now I moved onto the other clonk. Bearing in mind the vehicle’s age and mileage I had a nasty feeling that I already knew the answer to this one, but the first step was to check the propshafts for wear at the universal joints and splines, and to ensure that all the propshaft nuts were done up tight. I found nothing amiss, so with a sense of impending doom I undid the six bolts that fasten the PTO drive cover to the back of the transfer box. I jacked up the back wheels an inch off the ground, selected first gear, released the handbrake and shone a torch onto the inside of the transfer gear where it is splined onto the mainshaft, then rotated the handbrake drum back and forth. I was looking for movement between the shaft and gear indicating wear on the splines, and that is what I found – lots of it.

This is a well-known weakness on the LT230 transfer box. The gearbox mainshaft transmits drive to the transfer box via a large internally splined gear supported on two taper bearings. When the vehicles were built the splines were lubricated with grease. Over the years heat and age causes the grease to harden and stop doing its job, so wear develops in the splines on both the gear and shaft. The metal particles embed themselves in the solidified grease, which then becomes a very effective grinding paste. The rate of wear escalates as the splines become more worn. Eventually there is no more metal left, you let the clutch out, there is a loud bang from underneath and you find you no longer have drive. Land Rover developed a very simple fix for this problem by cross-drilling the gear to allow oil to reach the splines. Unfortunately it took them until 1996 to come up with this idea. Cross-drilled replacement gears are available for all but the early transfer boxes, but when the splines on the gearbox mainshaft are badly worn (as in this case) the only answer is to either rebuild or replace the gearbox.

So I ordered a reconditioned gearbox from Ashcroft and set about removing the old one, an exercise that rapidly turned into an epic battle with rusty, corroded bolts, and screws that had turned into blobs of rust. I prefer to remove the seatbox and crane out the gearbox from above, as it is much easier to keep everything steady and level that way when you are working on your own. To make the job even more fun, the Ninety had obviously been a farm vehicle until very recently, and every time I touched anything, large lumps of dried mud fell onto my head and down the back of my neck. While the gearbox was out I