Looking for some suggestions on this noise i have on my type 9 g'box.

Basically it's fine 1st,2nd, 4th
3rd sometimes and 5th all the time.

The noise is loud sort of whining noise very different than that of the other gears.

Sorry but quite hard to describe the noise

Sounds like countershaft bearings, is in use in all but 4th gear, that is straight through on the mainshaft.

[Edited on 30/3/08 by r1_pete]

how difficult is it to replace the bearings?

Looking at the Haynes Sierra manual, I'd recon on it being the rear countershaft bearing, its a caged roller, and sits in the rear face of the main body of the box, retained by a circlip. Looks like a rear extension off at least, then you're faced with a 12 sided nut and 5th drive gear to remove, then the circlip and you MIGHT be able to get the bearing out without stripping the box.

I'm sure someone on here will have experience of the job.

Type 9's are cheap well atleast cheaper than trying to recon a gearbox yourself

Haynes do a book that covers the overhaul of the type 9. It is a waste of time to replace any one bearing, you need to replace them all. There are several Ebay shops that do complete kits for the job. As for buying another type 9, well maybe cheep, but could be as bad, or worse, than the one you have. You pays yer money, and takes yer choise. HTH Ray