Trans slips out of 3rd gear

[Rich A]

Hi and thank you for letting me join. Working on my first Model A. I have done much work to it and took my first ride down the road in it. First trip all good. But the second time coming up a slight hill at 35-40 mph as I came over the top and started down, backing off the throttle it slipped out of 3rd gear. Went back and did the same trip again, slipped out in the same place. It does stay in gear under load.
I have removed the shifting tower. Yes the ball is worn on the shifter, but does seem to move it into the locking detent. Is the detent a tight snap? well this is my first time touching a model a so I have nothing to compare it to. Have hopes of some advice by the symptoms I described. Doesn't or at least hasn't yet slipped out unload. Only when backing off throttle, use engine to slow and maintain speed. And thanks again for letting me join Rich

[Gary WA]

If the ball is worn will cause to jump out of gear or the detent plunger spring is weak or broken,or if the shifting forks are bent or badly worn! Welcome to the Ford Barn.

[Tom Endy]

There are a number of things that can cause a Model A transmission to jump out of gear.
See the attached.

http://www.santaanitaas.org/wp-conte...ut-of-Gear.pdf

Tom Endy

[rotorwrench]

The model A transmission doesn't have a synchronizer system. The front of the second/high sliding gear dogs onto the input shaft when high gear is selected. This mate's the input directly to the main shaft for 1:1 drive. If the slider doesn't engage all the way onto the input then it's not all the way in like it should be. The shift fork and lever as well as the fork detent could have problems. The throw out bearing could have wear or the input to main shaft bearing could have a problem if it's one of the modern replacements. Dog wear or sliding gear spline wear can be problematic too.

As was mentioned, it could be one of these problems or a combination of problems that is causing disengagement of the 2nd/high slider gear.

[Terry, NJ]

I believe it's caused by a soft input shaft. Since you have the top off the transmission, look up front where the 3rd gear engages the input shaft and see if the teeth are not worn. somewhere I had pictures of mine. Since for "high" gear (1 to 1 ratio) the spline on the sliding gear engages directly with input shaft. Play around with it, putting into gear and back out. If it's worn, you will see it. Sad to say, but the trans has to come out to replace the input shaft. I believe that they may be an aftermarket part that may not have been heat treated properly. Once you have the trans on the bench, check all other gears, shafts and bearings and replace as needed. You will note that the shift lever has to fit the shift forks pretty closely ( .500" ). Sometimes this requires welding to build up metal and the grind it down to the size. Be careful of the spring on the shift lever as it requires a special tool to compress. Also, be very careful of the rear spring when you take the axle out. This is the ,most dangerous part on the car. DO NOT TRY TO DISCONNECT THE ENDS WITHOUT A SPRING SPREADER! Disconnect at the top of he frame! Good luck!
Terry

[Rich A]

Sponsored Links (Register now to hide all advertisements)

I took the shifting tower apart. Shifting lever worn bad, the rest looks ok to me. But here are some pics. I have hopes that cleaning it up and replace the shifting lever may get me going temporarily. Save the trans rebuild for the winter. I am going to replace the shift lever, forks, plungers and spring. any opinions?