Winding noise in front diff
 

Curious to see if anyone has had a similar problem?
I run a 300 tdi defender and have noticed a winding noise coming from the front diff, especially in the straight through gear of 4th.
I have sought advice from a certain company up here and they suggested that it was the gear box and were adamant on their diagnosis but they were wrong.
I am aware that at 215000 k's there may be wear in the crown wheel and pinion and possibly the movement is making the noise.

My solution will be based around putting in a diff locker in the front and possibly the back. Should i purchase a 24 spline diff and just replace the lot?

Your help would be much appreciated.

Also has anyone been running 33x315x75 tyres?
I am wondering if they may be a little too big for the engine

Sounds like classic failing diff noise to me.

What would be the best way to help the failing diff

To replace it.

If you're installing lockers I'd get heavier duty axles.

Why would I need to upgrade the axle? What experiences have been noted? Apart from the obvious breaking.
Perhaps with a wider footprint there could be a greater need for the upgrade also.
Any tips on a good supplier?