Alright so symptoms have changed a bit. I have attached images and videos with before and after new shifter bushings. Before the bushings I took a video and it shows the no output in gear issue, and the spinning tires in natural. Post bushings It seem I have output in all gears but still also in neutral, but I'm getting a noise from the transmission. I'm not 100% sold it was the bushings making the difference and not something freeing up.

Edit: short version - I think a roll pin fell out.

The video is informative. If a person just accepts that something could break inside the transmission at first start after sitting for a short while it opens up possibilities.

My best guess is that the transmission is stuck in a gear, probably 3rd or 4th, and that's why you get movement when the shift lever is in the neutral position, and why you don't get movement when you actually shift in to 1st or 2nd. Because then the transmission is in two gears at the same time. It feels like you're shifting in to different gears with the lever on 3,4, and 5, but it's probably all the same gear. The driveshaft speed seems the same for all "gears" that move.

One thing that's known to happen is a retaining pin (roll pin) in a clutch fork can come out or break. So the fork becomes loose on the shift rod and doesn't move the sleeve. It's an easy fix once you get the transmission apart, just put a new pin in.

Just a guess but it looks like you'll need to pull the transmission and take it apart. You might find the roll pin in the oil or near the drain hole, before pulling it, just to confirm. Or it might be stuck in the side of the fork.

Part #7. Not sure where you'd get one but roll pins are pretty basic things. Probably take one to a hardware store and find a match.

Datsun Z Transmission Control Lever & Fork (5 Speed-FS5W7...

Edited April 12Apr 12 by Zed Head

Time to pull the trans and take it to a rebuilder. You do have a very strange issue.

Finally had some time to pull the transmission and take some videos. Only thing I don't think that showed up on video being limited by two arms is no matter the gear selection or trying to be in neutral holding the output or input shaft and turning the other either way wouldn't really work and binds. Looking at videos online it seems without a gear selected they should move independently without a gear selected if applying a bit of pressure. Leads me to believe something on the inside of gears on the input side is stuck. I'll also note whoever last worked on this transmission used WAY to much RTV sealing the transmission casings together making it a pain to break open.

At 1:20 in the second video when it should have been in neutral the shafts seem to be connected at 1:1 when you rotate them like it's in 4th gear. Did you find any metal fragments in the case? Seems like something might be jammed or broken around the 4th gear coupling sleeve. Not sure but I think that something like an insert could do that. Maybe a broken insert spring. Take a close look at each one. They're small and kind of hidden under the sleeve.

I'm not a transmission guy. I rebuilt mine - several years ago but... However, I don't think your evaluation technique is adequate. Many of the gears rely on the shafts being held firmly by the bearings they ride in and the bearing fully planted in the housing that accepts it.. A bit a misalignment in the shaft can impact the way the gears mesh. As do the shift forks and detent springs and balls. They are an orchestra that ensures everything is moved and held in the proper place as gearing is changed.

Normal wear in these transmissions is the bearings and bearings and seals are what a rebuild kit is made of. That's why the question of metal parts, chunks, etc. in the gear oil or attached to the drain plug. Usually it's not gear wear, it's bearings coming apart.

I may be a bit late to the discussion, but based on the first few posts, it sounds like the transmission may have been rebuilt by the previous owner, with incorrect snap ring selection resulting in insufficient internal clearance.

Excessively tight clearances can restrict proper lubrication of the gears on the shaft, causing them to overheat and bind. This can create a condition where the transmission appears to remain engaged even when in neutral. It would also be consistent with the noise you’re describing.

Do you know if the previous owner carried out any work on the transmission?

This reminds me of a customer where I worked years ago, he brought in a car with similar symptoms and said, “I just rebuilt the transmission and now it’s started doing this.” That was about 40 years ago, but your issue sounds very familiar.

History I know about the car is it was stolen and titled salvage sometime in the late 80s. My box of papers begin in the early 90s with listed 280z parts so I imagine that was when the 280z engine and transmission were put in by a previous owner, and not a shop because of how detailed the receipts are. When I drained the fluid it wasn't the clearest Ive seen and had a bit of medal on the magnet but no larger bits or anything crazy, and just seemed to me a while since the last change. I'll measure everything before pulling it part and see if anything seems weird.

I think that cgsheen1 and EuroDat are suggesting that drag, of some kind, is causing the shafts to turn in unison in your video in neutral, when they should be disconnected. But your earlier descriptions describes the engine stalling when it was in gear. That would be some serious drag.

I'd still be studying the 4th gear hub and sleeve and synchro ring. If a different gear was stuck you'd get a mismatch between input and output shafts. The shaft speeds are matched.

On the other side of the adapter plate 5th gear and reverse are on the same shaft. Reverse is just a whole gear moved to mesh with another gear. Non-synchro. 5th gear has a synchro. In the video you engaged reverse.

Overall, everything points to a 4th gear being permanently engaged. As the coupling sleeve moves toward the selected gear it engages the synchro ring. The ring contacts the gear cone and friction causes their speeds to match. When the speeds are matched the sleeve slides over the teeth on the gear, transmitting force. I'll bet that the 4th gear synchro is stuck to the 4th gear synchro cone for some reason. Maybe it's broken.

I am just exercising my brain, not an expert. But I do remember working on the puzzle in the past.

I'd take a really close look at the interface between the ring and 4th gear.

https://www.z-services.eu/en/internals/510-oem-synchronizer-ring-240z-260z-280z-280zx.html

Only had a bit of time to work on it today but definitely found something. I started taking apart the rear side due to my bearing puller not fitting the way I like on the front side. Found idk what to call it behind the rear lock nut with a little ball locker rusted or stuck with 5th gear. I don't really have any good pictures of just how nasty it looked but after cleaning and just throwing it back in since im just testing and I need to order new lock nuts etc. I was able to spin the sides independently with no gears engaged and each gear seemed to work. Not done yet though since in neutral there seems to still be quite a bit of drag and a pretty bad hang up but it still will spin just with some effort particularly spinning in one direction(curious if normal). I'll see if I can get some videos later.

Yeah,,, rust in the transmission wouldn't be my first guess.

Junkyard transmission? Flood vehicle?

Probably salvagable but you'll need to get as much of that out as possible. Also be sure you have the little metal scupper plate that feeds the rear gutter

On 5/3/2026 at 2:35 PM, AJackOfFewTrades said:

Found idk what to call it behind the rear lock nut with a little ball locker rusted or stuck with 5th gear.

Not sure what this means (ball locker?) but the rust looks like a bad sign. There are needle bearings under the gears that would be sensitive to rust and crud floating around in the oil, maybe even rusted themselves. The hubs are splined so you could argue that the rust there doesn't really mater. The question is, what about the other parts?

Are you tearing it all the way down for a rebuild?