Hello,

While looking at my transmission today I found out that the 3/4 Synchro is jammed on the 4th gear. Now I'm not sure if its because of dried fluid or what, because i can get it to jiggle back and forth. However, I cannot get it to disengage from 4th gear. It looks like all of the spring loaded keys are in place so I dont think that is the problem.



Does anyone have any ideas or suggestions on how to get the Synchro unjammed without destroying it? I didn't want to take a hammer or screwdriver to it before seeing if there is a better way.

Thanks,

Han

 

The keys are out of their correct place. The sleeve got slid out over them, they popped out, then somebody tried to slide the sleeve back; now they're on top of the 3rd gear blocker ring instead of down in the slots.

Push all 3 keys into the hub, slide em back forward about 1/8", then slide the sleeve back over them. Then slap your mechanic around a little bit and threaten him bodily harm if he does that again.

 

Excellent eye. When I was reading about the keys being out of place I was thinking they would be missing or marred up. Didn't even think that they would be over the blocker ring and causing it not to slide back.

Honestly, I'm glad that's all that looks to be wrong with it. I also read that the 4th gear blocker ring can get all chewed up and keep it stuck in gear. Hopefully this should be an easy fix and I should have it on the road soon.

Thanks a ton!

 

One more question. Is this something that did/could have happened under normal operation? If so, how can I keep it from happening again?

 

Overtravel of the slider isn't usually an issue unless the shift stop setup is faulty. Needless to say you forgot to slap your mechanic friend.

 

Technically I am the mechanic. While I bought the transmission used I have since torn it down to repair the 5th gear issue. It was during the teardown itself I noticed that it was stuck in 1st.

I did exactly as you said and got the keys to go back in and put the synchro in neutral. Then I popped it back into 2nd spun it a few times and I heard a "clink, clink, clink" which was the three keys popping back out. Fixed it a second time and spun it in neutral for awhile. Popped it back in first then spin it only to hear the dreaded clinking sound again.

I will fully admit that there is some end-play on the input shaft because the firth gear is off. Also the rear bearing race isn't fully pressed in, again because 5th gear is off and I have been spinning the main-shaft. I'm telling you this because I'm wondering if that may be the problem that it is locking in gear. If you (or anyone else) thinks that may be it then I will go ahead and fix my 5th gear problem, put some rtv on it and bolt her up. However, if you dont think that's the problem then I would like to try to fix it while the baby is apart.

I am thinking that i may be throwing the synchro too far by hand and that is causing them to pop out.

I'm also wondering if one of the springs have popped lose and that is causing the keys themselves to pop out. I haven't taken a main-shaft apart before and I am kinda worried about doing that myself. However, if its what has to be done, then done it will be.

Here is a video of the operation:
https://picasaweb.google.com/lh/phot...eat=directlink

 

Since the extension housing is off, the mainshaft can slide rearwards enough to create enough space between it and the clutch gear, for this to keep happening.

The problem isn't that the sleeve is sliding too far forward; it's that the hub (incl the keys) is too far rearward.

Slap your mechanic some more, since he obviously hasn't got the point yet, and tell him to QUIT DOING THAT until the ext hsg is re-installed.

 

Happy ending update.

Well my mechanic (now black and blue) finally got it. Installed the main fifth drive gear (on the mainshaft) then put the ext housing on and bolted it up. Put it in fourth, spun it and heard a click. Thought it was bad news until I went to move in into third. It went into third! Spun it and heard the keys click again, but it went into neutral and back into fourth. So while the keys are popping, they aren't getting jammed anymore. I'm guessing this is just normal operation for the things.

Now I have noticed that the 3/4 slider doesn't move as easy as the 1/2 slider. I can move the 1/2 slider by choking it with one hand and pulling. It takes two hands to get the 3/4 slider to move. I have done some searching and although there isn't a direct answer, I have gathered that it may be normal for the 3/4 slider to be a little more difficult. Also, once I get the fluid back in it, that may make the operation easier as well.

I'll let this thread sit until morning and if any of the stuff I said doesn't throw up any red flags I'll get my sore mechanic out of bed in the morning to put the 5th gear assembly in and bolt the tranny together for good.

sofakingdom and jmd, thank you for your help. You two really walked me...erm, my mechanic through things. I think think the sight of gears, sliders, and synchros overwhelms him a bit.

- Han

 

If you installed the shifter cover and tailhousing (with shifter block minus the spring/ ball) ypu would find the shift 4th doesn't pop the keys out.

 

Well I went to put the 5th on today and ran into another problem. I have 1/2, 3/4 in neutral and the 5th gear engaged. Spins freely until it gets to one poin and I really have to force it to keep it turning. I will admit that this problem may be due to the fact that I am turning it without the tailhousing on, but I did my best to keep the bearing race set with my hand. Just wanting to see if this is normal or if there is something else that has popped up.

Here is the video:


Thanks once again,

Han

EDIT: Since the video and post I have bolted up the tail-housing to test. Still gets resistance in that one area. When I engage 1st or second gear I still get resistance. Maybe this is just normal. I can still turn the input shaft by hand, it just encounters resistance in that one area and takes a little more effort to turn.

 

I marked the gears and it is binding in one spot. I took the 5th driven gear off (the bigger of the two) and spun the little gear while it was still on the shaft. I could see it wobble with the naked eye. However, once I took it off and spun the shaft it looked perfectly straight. I also bolted up the tail-housing and put the transmission in gear to see if the output shaft had a wobble to it. It did not. This leads me to believe that the gear may be out of round. Has anyone ever heard of this happening? I know this is really against common sense, but I don't see how the shaft could be bent at the 5th gear area and be straight when it exits the tailhousing.

 

It's not common. And I agree that you need to have the tailhousing installed before testing it again.

All bearings from input back to the one held by the tailhousing need installed properly. That means the tailhousing. So do those on the countershaft since the 5th speed gear is there. And 5th driven, it's spacer if it has one, and the snapring need on there.

 

Installed everything. Still binding in that one area. However, I'm not seeing any out of round from the output shaft where it exits the tail-housing.