Gearbox clunk

[Apis Mellifera]

Hopefully this isn't an expensive clunk...

I have a '73 88. Just as I let off the throttle for a gear change, I get a clunk from the gear box. Letting the clutch out and giving it throttle after the gear change produces the same clunk. I can vaguely feel it in the gear lever. Any ideas? It's not the U-bolts.


Also, I've read the suggestions about checking the tightness of a gearbox shaft nut somewhere, possibly to correct a vibration, possibly the output shaft. I know that's a vague description, but does anyone know the location of this mystery nut (pictures?)?

Many Thanks
Matt

[KevinNY]

I'd also check your engine mounts and transfer case mounts.

[bearcrawl]

Remove rear prop shaft, in the center you will see a castle nut that should have a cotter pin through it. Also check the mainshaft nut. If you have a overdrive you need to pull it off and i will be clear. It's the funny looking nut over the shaft that holds everything together. 100 ft/lbs. No O/D just take off the backing plate and inspect.

Here is what the shaft will look like if it's missing the nut. Nut goes over the shaft and holds all together
http://i136.photobucket.com/albums/q163/rldahllof/IMG_2001.jpg