Always wondered how long they would run. A place I used to work had a 365 that had just tripped 2200 hours on a single cyl. Kawasaki. It was sold 3 years ago, so quite possible it is still on the job.
very possible. i have painted the wheels and the deck. replacing all the worn pieces that i could before i repainted it. this past Sunday it flipped 1,000 hours.
The 320 has the liquid cooled Kawasaki 18hp liquid cooled V twin. The only weak point to these motors is the factory plastic cam gear they came with from the factory. If it ever does fail the replacement cam gear is now steel. Some people replace them with the steel gear before they fail just for piece of mind.
The other weak point is the original fuel pump which has also been updated to a better design if you replace it.
With that said these motors can go 5,000 hours if maintained properly. I have seen running 320/345's with 4,000 hours and just last fall seen one for sale locally with 3,000 hours on it. The 320 was one of the best garden tractors John Deere ever built.
If you take care of it it will outlast you.
Keep in mind a liquid cooled motor will typically last 3 times longer than an air cooled motor.
Another thing you might do is replace the fluid and filters in the Sundstrand BDU-21 hydro transmission if it hasn't been done. Also while power washing make sure you clean off any caked on dirt/grease off the transmission and differential. Caked on dirt/grease will make it harder for heat to dissipate. The Sundstrand BDU-21 is a very heavy duty transmission that has a life expectancy of 5,000 hours.
Even with 1,000 hours your 320 will still outlast many brand new John Deere's.
The 320 was built back when JD built them to last a life time.
thanks for the hints. i have replaced all belts, hoses, antifreeze, hydro oil and both filters, washed the transmission, replaced gas line under the deck pan, new front end bushings, fuel and air filters, and cleaned cooling fins on the top of the engine. i use all JD parts as well as JD engine oil and hydro oil. i thought i might replace the cam this fall. i don't know if i need to do that now or wait.