LT77 clicking loudly in 5th gear

On the drive into work today (30miles) 5th gear began to make a rhythmic clicking noise. It only happens when under load, so lift off the throttle and the noise disappears. Only happens in 5th no other gears are effected and all are quiet and normal. It does change slightly with speed and increases as speed does but not by a huge amount, seems to be roughly 120bpm. Clutch is functioning as normal. Assume it is not clutch, engine, transferbox, or axle as it only happens in 5th gear. Same speed in 4th gear and there is silence.



I am running an LT77 box behind a 200tdi. The gearbox was rebuilt by Ashcroft from memory about 45k ago. Everything seems to be working as normal driving as normal just have this noise.

I know on the r380 this is a fairly common sign that the rear bearing is beginning to fail, is this the same for an lt77?

Anyone any suggestions what it might be or other test to undertake on the drive home/tomorrow on the drive?

Noise got significantly worse on the way home. Plan to drop the oil tomorrow and have a look, but am really after if it is definitely the gearbox or not if so I will pull the box tomorrow as well and get onto Ashcroft to se how quick they can refurb it again.

Sound on:

Can not say specifically about Lt77 but that is the sort of noise a failed bearing can make.

tottot said:

Can not say specifically about Lt77 but that is the sort of noise a failed bearing can make.

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That was my concern. Assume I am correct in saying gearbox as is it doesn’t happen in any gear other than 5th. So unlikely to be another part of the drive train. Also a little Annoying it was such an instant failure rather than usual becoming a little Noisy and then slowly getting until actually howling giving time to plan the swap out.

The 5th gear is sort of an add on extra in the Lt77 and R380 box, some say it is just not that well designed.
TVR car owners often have issues with the same box