Hi nooni, and welcome to Outdoorking.
It appears either your belt or your forward clutch is slipping, and you need to find out which. Unless your ratchet mechanism on the spring-loaded idler pulley has a fairly odd kind of fault, it seems belt slip is the less likely explanation. The usual process is to lever the idler pulley forward firmly, in the hope of reaching the next ratchet position. If you measure the distance between grooves on your notch bar, and measure how far the pulley moves when you lever it forward, you can see whether it is moving about as far as the distance between notches, or some lesser distance. If it is moving the full pitch between notches but is not latching into place, you have a ratchet fault. If it is moving substantially less than that, it is more likely your clutch is slipping. You can probably verify that though, by pointing it up a steepish slope that it won't climb, pushing the clutch pedal firmly for five seconds, then stopping the engine quickly and touching the forward clutch plate. If it is hot, you know where the slipping was occurring - check that the clutch pedal adjustment is correct before blaming worn friction material though. If the clutch plate does not get hot, you may have a worn or incorrect belt that is bottoming in the pulley groove. On the face of it though, the most likely problem is a worn forward clutch. Relining the clutch is not a big job if you follow the method described in several threads here on Outdoorking.
So far as your steering is concerned, it sounds as if you may have a problem with the left wheel turning too far due to alignment issues. I'm unclear on whether your tractor has lock-stops to limit wheel movement, or just relies on the limit on how far the steering sector will turn. Most likely either the left lock-stop is damaged, or the set-up of the steering sector or toe in is incorrect. The only specific information we have is the parts list, and that does not help answer the questions.
If you can't trace the faults from these suggestions, please post some pictures to clarify the issues so we can discuss them further.
