654 Transmission

[ML3 1,253]

Was grading out some thin topsoil w/my 654. Going forward just fine. Went to go into reverse & tractor stalled when clutch was released. It stalls when clutch is released in all 3 forward gears & reverse. Can't get transmission into neutral. Seems like it's possibly stuck in 2nd gear? If I let clutch out tractor moves forward. Pulled belt guard & belt (new) is fine. Something internal in transmission????  

[ri702bill 8,480]

Since that is an early 4 speed, it is possible you have it stuck in two gears at once, hence the stalling. The "fix" came out in 1965, a year after yours was made. Shallow flats were added on the shift forks to aleviate a hydraulic lock.

Check to see that the transmisson is in neutral when you shift it there. Remove the shifter and boot, look down the hole and the notches on either side should be aligned (there IS a picture of this procedure in the Transmission Section) if they are not aligned, GENTLY rock the tractor back and forth while using a large flat blade screwdriver to move the block that is not centered. Once neutral is established, the tractor will roll. Reinstall the shifter and boot - be sure the dog point pivot screw is in the hole on the "ball". Tighten until tight, back off about a quarter turn. Tighten the jam nut - recheck the function.

Three causes for the issue - the pivot screw was adjusted too far loose, "Speed shifting" is a problem - shift slowly, only when stopped. Too heavy weight gear oil in the Unidrive - 140 weight is too heavy, use 80/90 weight. The only REAL fix to prevent the hydraulic lock is to vent it - need to disassemble the Unidrive and either modify the forks with flats added, or replace with the later style...... I did substitute the later forks on the 1962 502 Unidrive I went thru last fall.

Edited June 14, 2023 by ri702bill

[ML3 1,253]

5 hours ago, ri702bill said:

Since that is an early 4 speed, it is possible you have it stuck in two gears at once, hence the stalling. The "fix" came out in 1965, a year after yours was made. Shallow flats were added on the shift forks to aleviate a hydraulic lock.

Check to see that the transmisson is in neutral when you shift it there. Remove the shifter and boot, look down the hole and the notches on either side should be aligned (there IS a picture of this procedure in the Transmission Section) if they are not aligned, GENTLY rock the tractor back and forth while using a large flat blade screwdriver to move the block that is not centered. Once neutral is established, the tractor will roll. Reinstall the shifter and boot - be sure the dog point pivot screw is in the hole on the "ball". Tighten until tight, back off about a quarter turn. Tighten the jam nut - recheck the function.

Three causes for the issue - the pivot screw was adjusted too far loose, "Speed shifting" is a problem - shift slowly, only when stopped. Too heavy weight gear oil in the Unidrive - 140 weight is too heavy, use 80/90 weight. The only REAL fix to prevent the hydraulic lock is to vent it - need to disassemble the Unidrive and either modify the forks with flats added, or replace with the later style...... I did substitute the later forks on the 1962 502 Unidrive I went thru last fall.

Thanks. I'll look at it this weekend. Maybe sooner if I get a chance. Ended up having to pull snowblower off C105 & put blade in it to finish the job. Probably a better tractor for the job anyway but the 654 is more fun to operate. 

[ri702bill 8,480]

Gotta love a Round Hood....

[Racinbob 11,196]

The flats on the rails helped but didn't totally resolve the issue.Some time before that they issued another service bulletin stating that 40w lube should be used to help. A much more positive fix was service bulletin 60. 

 

 

Old rails on the right, newer on the left.

 

 

This was a newer version which was most likely due to manufacturing process changes. They are fully interchangeable. Keep in mind though that there is a difference in the first/reverse and 2nd/3rd rails. Note the center detents, 

 

 

Make sure you use the longer 3/4" stop pin if you put the newer rails in otherwise is won't help. 

[ML3 1,253]

5 hours ago, Racinbob said:

The flats on the rails helped but didn't totally resolve the issue.Some time before that they issued another service bulletin stating that 40w lube should be used to help. A much more positive fix was service bulletin 60. 

 

 

Old rails on the right, newer on the left.

 

 

This was a newer version which was most likely due to manufacturing process changes. They are fully interchangeable. Keep in mind though that there is a difference in the first/reverse and 2nd/3rd rails. Note the center detents, 

 

 

Make sure you use the longer 3/4" stop pin if you put the newer rails in otherwise is won't help. 

22 hours ago, ri702bill said:

Since that is an early 4 speed, it is possible you have it stuck in two gears at once, hence the stalling. The "fix" came out in 1965, a year after yours was made. Shallow flats were added on the shift forks to aleviate a hydraulic lock.

Check to see that the transmisson is in neutral when you shift it there. Remove the shifter and boot, look down the hole and the notches on either side should be aligned (there IS a picture of this procedure in the Transmission Section) if they are not aligned, GENTLY rock the tractor back and forth while using a large flat blade screwdriver to move the block that is not centered. Once neutral is established, the tractor will roll. Reinstall the shifter and boot - be sure the dog point pivot screw is in the hole on the "ball". Tighten until tight, back off about a quarter turn. Tighten the jam nut - recheck the function.

Three causes for the issue - the pivot screw was adjusted too far loose, "Speed shifting" is a problem - shift slowly, only when stopped. Too heavy weight gear oil in the Unidrive - 140 weight is too heavy, use 80/90 weight. The only REAL fix to prevent the hydraulic lock is to vent it - need to disassemble the Unidrive and either modify the forks with flats added, or replace with the later style...... I did substitute the later forks on the 1962 502 Unidrive I went thru last fall.

Thanks. I'll look at it this weekend. Maybe sooner if I get a chance. Ended up having to pull snowblower off C105 & put blade in it to finish the job. Probably a better tractor for the job anyway but the 654 is more fun to operate. 

[ML3 1,253]

Hopefully I don't have to go into transmission. I hate working on them. I wasn't "speed shifting" it & it has proper weight gear oil, which I just flushed. When I got tractor the shift boot was all torn up so diff fluid was definitely contaminated w/water. I did a thorough flush 3x 

[ri702bill 8,480]

All good - BUT, as I said the only permanent fix is for vent-relieving flats (which CAN be added to your original forks.) The "trouble" with opening one of these up - the more you look, the more you find.. And that, as we all know, runs into money (well spent!)

[Racinbob 11,196]

Actually the vent relieving flats only helps the problem but doesn't eliminate it. Service bulletin #60 provides a positive mechanical stop. Prior to the flats Wheel Horse had issued another service bulletin stating that 40w lube should be used to help alleviate the suction. That even made it in some of the owners manuals and they neglected to switch it back to the heavier lube after a real fix was done. 

[ML3 1,253]

I was able to finally look at transmission. It was indeed stuck in 2 gears. The screwdriver, rocking method worked. The pivot screw did seem like it was kinda loose?? I reassembled it now everything is working. 

 

Thanks to all for the tips! 👍