12 hours ago, Zed Head said:

I've heard of that problem but not actually seen someone have a 5th gear issue as bad yours.  Something to be aware of.

Just went out and looked at one of my extra shift levers and it has much deeper gouges than yours, same spots,  But I never had a problem.  Weird.

I think Lumens hit the nail head with the short nose and the long nose differences.  I have some measurements to get together for Dave WM and will post later.

Thanks Zed Head. 

I am going to go take a close look at mine today and see if I can see any marks on the shifter (before I try to install the trans).

Edited May 16, 20168 yr by Dave WM

I took a quick measurement of the two.

The long snout is 2" from the very bottom to the center of the hole.

The short one is 1 3/4".  So a quarter of an inch difference is what I'm seeing.

The ZX one with the square hole and spring is what I'm using now, it works the best to me.  It's in the car now and I have a two o'clock alignment appointment so I can't measure that one yet.  Maybe tonight?

I looked at mine I just cant see how it could possibly hit anything. I will get a video up later to try and clarify. I assume the interference is with the transmission and NOT the car tunnel? based on where the grind marks it would be pretty deep in the shift part (cast iron part). I don't see how a different length would even work unless the short one is just barely catching the shift rod while the long one fully seats. Ok checked 1.75 or 1 3/4 inch.

Edited May 16, 20168 yr by Dave WM

Yes it hits the cast iron part. I don't understand how that works either, sorry.  I've been driving it all morning and have decided to have the longer one welded to the short snout one that works in 5th gear.  The rubber boot under the leather boot has already torn with the straighter shifter. 8^(

One step forward two steps backwards.  Makes me want to drink! (doesn't take much, a mosquito bite?)

Anyway she's getting aligned as I type.

ok I get it completely now, saw the same marks, used a dermal drum sander to reshape along the problem areas. Remove a little bit go check do again.

Now I can shift and clearly see the detents are locking in before the shifter comes into contact with the oval hole on the striker rod head (that is where the marks come from. Glad I did this before installing, its much easier to see what happening with a bright light and getting close in.

We learn from other's mistakes.  There's some good teachers here! 

 

After looking at a few 5spd shift rods they all have some kind of mark on them.  The ones with the square opening and spring do not.  maybe Nissan saw this and did a fix?

the dia of the shaft looks noticeably smaller on the ZX shifter, try measuring up from the bottom to the marks and get a dia there, then do the same on the ZX shifter.

On my ZX trans the rev idler gear was pretty chewed up. I noticed when the trans was apart that even when fully engaged the rev idler was only about 70% at best in mesh with the main shaft straight cut gear. I also noticed that the rev position of the shifter was the worst position for the clearance issue (marks). I wonder if when shifting the reverse gear was even less engaged than the amount noted when I had it apart? Anyway I have ground it such that I can fully engage reverse now as well with a tiny bit of play left after the detents take over.

You're right. I'll study it a little more before I go cutting and welding. 

The little reading I did  on the rectangular shifter hole with the spring keeping pressure on it says it keeps vibration out of the shifter rod and the pressure from the spring keeps it in the neutural position when not in gear. 

Thank you for your input, it helps my decision making. 8^)

The design looks to me to be an attempt to allow the bearing cup on the end of the shifter to move in a more lateral motion to stay fully engaged in the shift rod head. The fixed pivot point of the Z shifter the bearing cup will move in an arc line, slightly pulling away from the shift rod head when not in neutral. I would have assumed this was accounted for in the design of the orig shifter and not have been enough to cause a problem. The movable pivot point on the latter resolves this by extending the radius line as it moves off neutral, but I would think at the same time in introduces more plastic wear surface into the entire mechanism, fine in the short run but likely to get loose with a lot of use. Engineers love to change things (star trek the motion picture).

Just to clarify the shifter difference I had posted. That was what my problem was on my 1978

280 5 speed install. Not a ZX gearbox. I thought you had the same 5 speed I had.