4 PIN CENTRE
A standard 2 pin diff centre, as fitted to all Discoveries, Defender 90's and Defender 110/130 front diffs can be a weak point in the drive train as the single cross pin can either friction weld to one of the planet gears which then spins and wears the casing hole or they can just shear, either way the 2 pin stock diff will not take much off road abuse before failing. They also wear prematurly if the traction control is used excessivly ie in sand etc.
4 pin diff centres are machined from Billet EN24T and have the larger 18 mm diameter cross pins fitted. This means the 4 pin diff centre is much stronger and more reliable and not prone to the failure that the 2 pin diffs suffer with.
The casings we use are provided by Nigel Barker at Xcess 4x4. There are several reasons we use Nigel's casings. One being that no modification is required to the ATB or other diff centre. Unlike other pegged casings available where the centre requires 5mm or more turning down on a lathe. The quality of the welding and machining is second to none.