Transmission problems

[YanmarEd]

When I backed my YM1700 off the trailer this evening I heard a loud clunk then It acted like the transmission locked up would not move in any gear I played with it for a min then I could move the tractor in 3rd and 5th 0r 4th and 8th the pto works fine but nothing happens when i put it in 1st or 2nd any ideas what might be wrong ? is this somthing I can do or should I take this to my mechanic ?

[clemsonfor]

sounds like either a bering or shaft let go. i would pull the top off of it, not that much to it, then you will be able to see inside the tranny.

[winston1]

Not really an answer whether you can do it or not but you might remove the shifter and take a look. Might be a damaged fork or ?. Might could see what is damaged. Don't think it is that complicated to remove the shifting fork housing either. If you have damaged gears it is going to get serious. Do you have a repair manual? The shifting fork housing is ref #16 in the second drawing. Have I ever done this? NO. Would I do it? Yes. Yanmar Tractor Parts: SHIFTER Yanmar Tractor Parts: TRANSMISSION_EXTERNAL

[svcguy]

While it's difficult to assess accurately on the information provided, my first guess is a shift fork has either worn out and jumped or has broken. The transmission locking up leads me to believe something fell down into the gear cluster and jammed the transmission (probably a broken piece of fork). The fact that you could shift into some gears (fork still intact) but not others (fork broken) would make sense. I would remove the transmission cover (with the stick shift), lifting straight up if possible and make note of the shift fork placements (you will see where they fit on the gear shafts just by looking). Another possibility is a broken shaft, but it makes less sense with you simply backing off a trailer. Manual transmissions are straight forward and easy to understand, but you should not attempt repairs without a service manual if you need to disassemble the transmission. With a service manual and good tools, it should be no problem if you like mechanical things. My immediate thought is that by simply removing the cover, you will find a broken shift fork and repair is simple - get a new fork, place it back in exactly the same place with the same orientation, using the same dimple (on the shaft) from the original locking screw.

[svcguy]

For example, this is a picture of a Massey Ferguson 135 transmission with the cover off. This is a simple shift pattern, R, 1, 2, 3 provided by the two sliders forming the rectangle opening and two ranges covered by the single slider above. All manual transmissions are very similar.

[YanmarEd]

For example, this is a picture of a Massey Ferguson 135 transmission with the cover off. This is a simple shift pattern, R, 1, 2, 3 provided by the two sliders forming the rectangle opening and two ranges covered by the single slider above. All manual transmissions are very similar.

Tank you I will pull the cover off early next week it is late thursday now and I am heading to the hunting camp tommorow after work thanks again Ed

[YanmarEd]

While it's difficult to assess accurately on the information provided, my first guess is a shift fork has either worn out and jumped or has broken. The transmission locking up leads me to believe something fell down into the gear cluster and jammed the transmission (probably a broken piece of fork). The fact that you could shift into some gears (fork still intact) but not others (fork broken) would make sense. I would remove the transmission cover (with the stick shift), lifting straight up if possible and make note of the shift fork placements (you will see where they fit on the gear shafts just by looking). Another possibility is a broken shaft, but it makes less sense with you simply backing off a trailer. Manual transmissions are straight forward and easy to understand, but you should not attempt repairs without a service manual if you need to disassemble the transmission. With a service manual and good tools, it should be no problem if you like mechanical things. My immediate thought is that by simply removing the cover, you will find a broken shift fork and repair is simple - get a new fork, place it back in exactly the same place with the same orientation, using the same dimple (on the shaft) from the original locking screw.

Thank you for the info I have pulled the cover and sure enough the 1st and 2nd shifter fork is broke . I have a new one on the way but have some questions. 1. How do I remove the Pin that holds the slide shaft in and then do i just drive the shaft out after iremove the pin ? I have a service man but it is not real clear on how to remove this part any help woud be appreciated thanks Ed

[winston1]

Looks like a roll pin, assuming there is a hole all the way through I would think drive the pin out, same with the shaft after pin removal.

[YanmarEd]

Looks like a roll pin, assuming there is a hole all the way through I would think drive the pin out, same with the shaft after pin removal.

thank you for your reply but the hole does not go all the way through thanks

[winston1]

Never seen a rollpin that didn't have 2 way access. First for everything. How about an extractor to pull the rollpin?