Diff and box

[LordGrover]

I have a 'spare' diff and gearbox amongst the many bits I've gathered over the past year or so. I have no idea whether they're any good - just bought them as they became available.
Any recommendations on who or how to check them out?
Or should I just send them somewhere and say 'Refurbish that please.'?

(NB. my competence level is verging on the negative, so unless a quick shake or wiggle can tell me I'll have to take them somewhere).

[optimax sniffer]

Does that mean that the griff has gone?

[LordGrover]

Oh no my dear Sniffer! Far from it.
That's why I need to get these bits sorted for when I need them.

[anonymous-user]

Try John Reid of Readman Racing - top bloke says me