hi, i have a k40 4 speed gbox and it was working fine untill the other day when i noticed that when i change

down from 4th into 3rd it seems (at 60kph) to make a vibrating or rattling or gear clashing sound.

if i accelerate hard in 3rd (3.5k to 4.5k rpm) and let go it sill does it.

can someone please help because the sound is starting to get on my nerves!

thx Scott

Its hard to make a 100% diagnosis with that info, so it could be a couple of things.

Input shafts sometimes get noisey so it could be that.

Its also common to chew out the lay shaft rod though, and this will make more noise in 3rd (using the layshaft) than it will in 4th (locked main shaft).

 

If its only a K40, I'd just try and find another one in good condition for around $50. Or take the opportunity to upgrade to a K50 for around $150.

ive got a K40 for sale in perfect working order for you if your interested. in Taylors lakes vic pm if intrested