Sud gearbox help
I'm in a bit of a bind. The gearbox in the sud started playing up this morning. When it's in 1/2/3/4/R, there is an knocking/grinding coming from the box. It's the kind of noise I'd associate with imminent failure. But in 5th, its perfect.
The first sign of trouble came while climbing an onramp between 2 motorways. I dropped from 5th to 4th (at about 45mph) then about 15-20 seconds later, the noise started. I had been on the motorway for about 20mins before that so hadnt been shifting at all.I had to go another 100k to get back home and once I stayed in 5th, the box was silent. Any other gear sounded like a bag of spanners.
I've taken the inspection plate off the bottom of the gearbox(expecting to find lumps of metal in the oil) but there's nothing. No scoring on the gears, no lumps of bearing hanging out etc.
If it was there in all the gears, I'd put it down to a bearing or something, but the quiet 5th gear has thrown me completely.
Can anyone give me some pointers to check visually? The Section of the Haynes manual dealing with the 5speed box is good for a laugh but not much else.
Any advice would be greatly appreciated.