Transmission internals question

[redfogo]

I am in the middle of swapping the case on my 5speed 83 trans I decided to shift things by hand and inspect syncros make sure everything looked okay before put it back together. I have never used this trans so I am only going off of the fact the PO said it was good. I noticed that when shifting into reverse it gets stuck unless I rotate the input shaft counterclockwise in order for the little keys to grab the syncros to put them into place then it will let me shift out just fine. If i am not mistaken the input shaft always rotate clockwise?  I have never taken a datsun trans before so I am a little new to the internals work. I assume what I am seeing is normal but I figure I should ask before i put it all together only to find I have an issue.

[Zed Head]

@Dave WM and @EuroDat have been deep in to the 5 speeds.  They might have some thoughts.

You might be looking at 5th gear.  Reverse does not have synchros in 1983, it's the straight-cut gears.  Reverse and first are the only two gears where shafts might not be rotating when shifting.  All of the others will have the output shaft rotating with the propeller shaft.  Without oil things do tend to get sticky.

When you put it together make sure that it's not locked up after.  It's possible to get it in to two gears at the same time when putting the front case on, because the shift rods will move.  Most people put it in to a certain gear like 2nd or 3rd then put the case on.

[redfogo]

I made a video to maybe help explain myself

 

[Dave WM]

IIRC those shift dogs (3 spring loaded parts mounted around the hub of the syhcro) should be locking the brass baulk ring to the hub. With it in neutral can you spin the brass ring while holdng the output shaft still?

[redfogo]

When it's in nuetral it moves about one tooth width forward or backward depending on the position it was left in. 

[Zed Head]

The synchro that you're looking at is the 5th gear synchro.  I haven't really studied the way that Nissan added 5th gear to their 4 speeds but it looks like they made the reverse gear in to the coupling sleeve for 5th.  Pretty cool.  When it's uncoupled to 5th it's used as reverse.  Dual usage.  Never realized that.

5th gear will be engaged when you're cruising down the free way at 60 mph and those parts are rotating.  Not sitting, with no rotation.  You might be making much from not much.

[redfogo]

Right but my fear is with reverse getting stuck and not coming back out unless thing are aligned right. Regardless i think your right with the idea being I am probably making much from not much

[EuroDat]

Watching your video, its hard to tell what going on. Reverse can be a bit iffy when selecting it like that on a bench like that.

I'm not sure if its something to worry about or just leave it and move on.

[Dave WM]

Those shift inserts should not be disengaging from the balk ring. That would be the only thing to worry about, cant really tell from the video.

I have to reassemble mine later this week, will get some video to show you what I am talking about.

[redfogo]

That be great thank you!

[Zed Head]

3 hours ago, Dave WM said:

Those shift inserts should not be disengaging from the balk ring. That would be the only thing to worry about, cant really tell from the video.

They do seem exposed.

The ends of the shift rods are all stopped by the front cover.  You might make sure that all three rods are on the same plane and see if the inserts are still exposed.  Could be that the coupling sleeve is just moving farther than it will when everything is fully assembled.

[redfogo]

Sorry I'm not 100% sure what you mean by shift incerts? You mean the keys inside the gear that move back and forth?