Transmission internals question

[Dave WM]

Eurodat, you don't think that insert is in backwards? I assumed the damage was done in reg use where the top of the insert was routinely popping up (in the rev installation of the insert I don't think it would be possible for that to happen), and the damage done by attempts to get out of reverse jamming the coupling sleeve into the exposed top while the baulkring was not indexed. after repeated attempts rotation of the output shaft would eventually allow the cut out on the baulk ring to get back and then the insert would find its way back in.

Edited November 18, 2017 by Dave WM

[Dave WM]

I have to put mine back together, when I do I will mount the adapter plate and try moving it (nothing to stop the shift rod) and  see if I can overshoot on the coupling sleeve.

[Dave WM]

took a measurement before removing bell housing, attached pic and mech drawing of how I see it should go. this shows how much of the pad on the top of the insert shows when in the rev position with bell housing on and how much of the hub is exposed. approx. 1/2 inch of the hub is shown while in rev, note how close the coupling sleeve is to the bearing plate as well. You can see that only a fraction of the pad is exposed, so there would be no way the coupling sleeve teeth could get behind it in normal use. OP should get a measurement of the hub at the 1/2" mark as well and see if the pad is still under the coupling sleeve. I have added the cross sectional again for comparison of orientation of the insert. I did see several exploded drawings in my research, some had it as the OP, some had them both ways (one insert with the long side pointing back one with it going forward), and I found on a C version which uses the same type of sycro the longs side of the insert all facing the back. For that reason I trust the cross section drawing.

 

there is no damage to the shift insert like shown by the OP.

Edited November 18, 2017 by Dave WM

[Zed Head]

Boiled down the essential elements - it works right when it's fully assembled.  But it's worn.

Isn't that about the state of the situation?

Dave, is that a busted oil gutter in your picture?  Or is it something else?  Doesn't really look like the factory jobby.

Don't overlook your oil gutter, redfogo.

[Dave WM]

that's the other side of the gutter. His may work, but I suspect it will not work as well as it should. The  main thing I see is the damage to that insert, Seems the only way to account for that is improper assembly, looks like a lot more than just reg wear and tear.

[Zed Head]

Seems like the only way to get it improper would be if the hub was not pressed on completely.  Maybe that would show at the nut, if not threads are showing.  Other measurements too, of course.  Maybe the nut is coming loose.

[Dave WM]

8 minutes ago, Zed Head said:

Seems like the only way to get it improper would be if the hub was not pressed on completely.  Maybe that would show at the nut, if not threads are showing.  Other measurements too, of course.  Maybe the nut is coming loose.

very easy to just rev the direction of the insert, I know since when mine came apart I had to do research (the cross sectional drawing) to figure out the correct way to install. Pretty sure I tried it with them in the wrong way just to see what would happen, but I cant recall exactly the details (I vaguely recall it did not seem right). It was just a quick check and make sure it was right back when I 1st took it apart. the other real test was to look a were the spring is, it should be located under the pad of the insert, his is not, its in front of the pad on the insert. when the collar goes forward, the pad is exposed and the insert lifts up in the back, loosing indexing.

Edited November 18, 2017 by Dave WM

[Dave WM]

here are some pic I took at the time, just found them. note the spring hole is just forward a bit of the center cut line on the hub. in the second pic you can see how the spring will be located directly under the pad on the insert. You can assemble either way, but IIRC it was popping up oddly when the coupling sleeve was pushed forward when configured as in the 1st pic. I am trying to recall this, I cant remember if I posted about it in the orig rebuild thread. It was just one of those things that I had to deal with since when removing the sychro, the coupling sleeve popped off and the insert went flying. I had not intended to take it apart. On the other sychros I was more careful to remove as a complete unit.

 

Edited November 18, 2017 by Dave WM

[EuroDat]

Hi Dave,

I was thinking that too, but it's been two years since I have had one of these later 71B versions apart and 5 years ago for my own transmission. Ther reason why is because I remember problems with the manual. It shows the inserts in both directions, depending on which diagram you look at. I did make a simple sketch when I pulled mine apart last time, but I can't find it now. See the two drawings in "5th shifter inser.jpg" for what I mean.

Looking at the snapshot I made, I would be 80 - 90% sure it is in backwards. It also explains the damage to the insert. The assumption that this is the first time the transmission is apart would not be correct. If someone pulled my transmission apart, they could make the same assumption, because I used new bearing retainer screws and nissan gaskets.

I can pull the rear extension from one of my spares tomorrow and check. 

[Dave WM]

That would be great I know Red would like some verification, I noted errors in the exploded pics as well. on some of the manuals it was the other way on the exploded. one had both ways on the same pic. I am surprised that the manual did not deal with this better.

Edited November 18, 2017 by Dave WM

[EuroDat]

9 minutes ago, Dave WM said:

That would be great I know Red would like some verification, I noted errors in the exploded pics as well. on some of the manuals it was the other way on the exploded. one had both ways on the same pic. I am surprised that the manual did not deal with this better.

Yes, It's an issue I had with the manual. The assembly section only warns you to mount the hub in the correct direction, but doesn't say anything about the inserts. They managed the neglect that all the way through to 1983.

It looks like they corrected it in the 300ZX 1984 transmission. 

[Zed Head]

I get it now.  That's some good deep-diving.

Here's another short summary - redfogo's inserts are definitely installed backward.  It might be that they will still work this way (and might be why Nissan never became aware enough to correct the manual) but it looks like there is damage being caused.  Red has to decide if he wants to disassemble the transmission far enough to fix them or just run it that way.

Any comments on how far he'd have to go to get to them, to replace and/or reverse?