mf 135 transmission gear gets locked up..help

[10backacres]

I have a 1968 mf135 deluxe gas 6 speed that if I put it in neutral while the tractor is still moving will lock up the gear train. I've fixed it by opening the transmission oil filler plug and using a bar I can move the gear free. I make a habit of not moving the gear selector to neutral until stopped. My question is what do I need to fix?

thanks for any help/ ideas

 

[big bubba]

not sure on the fix, but had an earlier version of your model (TO35) & the same would happen. exact same method of relieving the gear train bind. with that old a tractor, may not be worth it. fine tractor though, had mine 28 yrs. good luck

 

[Agvg]

Worn ball of the gear lever, weak springs on the shifter axle, you must lift the steering gear and splitting it between gear box and center housing.

 

[10backacres]

could it be a bad shifter fork?

 

[big bubba]

Worn ball of the gear lever, weak springs on the shifter axle, you must lift the steering gear and splitting it between gear box and center housing.

impressive reply. may not be worth other than full restoration, etc

 

[Agvg]

It's not a big job, but if you own old tractors things like this are a part of the charm

 

[10backacres]

Agvg the gear is always forced forward towards the steering gear casting and gear slides back easily on the rail once impingement is relieved

 

[10backacres]

The charm is not nearly enough ......7 days ago spreading the cowpies with a pasture harrow the water pump shaft gave in to fatigue split in half... now replacing a waterpump,pulley ,fan blade ,and radiator. I thought it was lift off time with the cloud of coolant!

 

[aczlan]

could it be a bad shifter fork?

It's possible, it is more likely to be the ball on the lower end of the shifter or the ball and socket that the shifter mounts into.
If those are sloppy it will let the shifter fork slide back and forth more than it should which will let it jam into multiple gears at the same time.
Here is a picture of a fairly simple six-speed transmission, 3 forward gears and a reverse gear (far side of the transmission) and high/low (near side of the transmission):

If your transmission is a more complicated one, say an 8-speed where there are 4 forward gears and reverse gear, you would have three sections on the far side not just too and when they are not engaged, unused gears are held in place by the little detent on the shift rail. If that detent is not still holding firm it could slide into gear while you are still in another gear.

Aaron Z

 

[Roadworthy]

Rather than just popping the tractor out of gear while rolling try depressing the clutch first. It might help and it can't hurt.