J/D 318 hydostaic drive.

[landerson]

Happy to be here, My 318 J/D I believe is getting close to Transmission rebuild or replacement. It slows down noticeably when climbing slight hills. My question is the problem possibly caused by the relief valves lifting and causing the fluid to bypass. Or possibly debris on the seat holding the valve open or leaking by ? I'm a new comer and learning my way around. It is great to able to talk to people who enjoy mechanical systems. In my case I sold a relatively new John Deere to buy a 1990 J/D 318. What made go that route is getting tagged two times for J/D plastic hood to the tune of about $ 650 a hood times two. Why hasn't John Deere gone to ABS plastic. I live in Maine and ABS canoes breed here, you can't kill them !!!!! I would really like to do this myself, because my Wife will never let me live this down, trading a fairly new tractor for used but BETTER tractor. Thank You

 

[oldnslo]

I am not sure if the 318 has reliefs in the trans or not. One thing to check is the towing valves to make sure they aren't stuck partially open.

 

[landerson]

I didn't know for certain myself. I stumbled upon them wandering around E BAY MOTORS, pretty expensive, two required for reversing the flow. I don't know what to do put the money into replacement valves or save up for transmission rebuild or replacement. I don't want to replace the trans. and find out it was the relief vales??

 

[oldnslo]

First thing check the towing valves. These are located under the seat on top of the transmission. They are operated with a lever ( i think on the right side) These can stick open If theyhave not been used for awhile and then they are opened so that you can push the mower with the engine off. From memory with the lever at rest the valves should be very close to touching the lever. I believe the push pin sticks out of the valves around 3/16" but I have never actually measure this height.

If these valves are stuck partially open it will cause the tranny to get hot and move slowly with little power.

 

[landerson]

Yes you are correct, exactly as you said. I will have to take the seat pan off the tractor to get access. Another question, are those valves responsible for regulating system pressure, or just in use as a bypass for moving the tractor with the engine not running? In other words are these the only relief valves in the transmission?

 

[oldnslo]

They are just for moving the tractor with the engine off.

In looking at the parts breakdown I don't see any reliefs. They might be integral to the tranny housing or the 318 may not have them as standard equipment. I know they were an option you could add on X485 model.