When I push the mower (with the out of gear lever pulled out) It makes a clicking sound. The bel tis woen out and needs replacing, but does that clicking noise mean the transmission has a problem??
Not necessarily. You may have to delve into this deeper tho. When you replace the belt, check for any possible external things which might contribute to the noise. Pay closer attention to the brake components. You will also want to know that there isn't excessive play in the top pulley or input shaft of the transmission as well while you are there.