Read this one

http://www.daihatsu-drivers.co.uk/node/16224

I have been driving around in 4H in the recent ice and snow. Having forgotten I had left the manual hubs engaged, I was going up the road (2H) and got the transmission grunt and vibration at low speed. On disengaging the hubs, the grunt went away immediately. Rude words, thought I, the poxy splines on the front propshaft have water in them again and it's still frozen.

It shouldn't have happened, because I have recently MOTd the vehicle and greased all the nipples beforehand. Obviously greasing the propshaft splines hadn't dispersed the water, so I dropped the shaft off to do a proper job.

As I expected, the new grease had only penetrated the splines near the nipple and rusty old grease was still on the other side. Cleaning things up and applying new grease, I decided to shove the rusty grease at the top of the spline (nearest the UJ) out of the bleed holes near the UJ. This was done by putting a large dollop of new grease on the end of the spline before I replaced it in the other half of the propshaft.

I had to use a large amount of force to squeeze the grease out of the top by putting one end of the propshaft on the floor, and the other on my chest and leaning on the shaft with all my body weight.

BINGO, the answer. All us good boys have been greasing the propshafts regularly and the cavity at the end of the splines is now full of grease. All it needs is the engine to shift around a bit on its mountings (which might be getting a tired after all the miles) and the spline will no longer slide to accommodate the engine movement, especially when the grease is cold on these winter mornings.

THE FIX. When you have greased the splines, you need to squash the spline to mimimum length to squeeze out the extra grease and leave an airspace to allow free movement of the spline. This also makes refitting the propshaft easier.

I have been driving around with the hubs engaged for about 30 miles since I did this and have had no more grunts.