75 280Z - 5 speed swap from 81 280ZX - any catches I should be aware of?

[HusseinHolland]

Z/ZX Gearing chart

After driving my 280Z 500 miles this past weekend, I can honestly say I can't live with the 4 speed until the drivetrain conversion happens. Mine is in rough shape - 3rd gear whines like a tractor gear set, and in 4th, the shifter rattles & the whole thing sounds like it's gonna explode when I drive over 80 for any duration. There were a couple sprints on the way down & home where I got up over 90, and the car felt pretty good (I had previously felt the nose to be a little flighty at speed, however I think that is mostly the roadway I normally drive on - since I did not experience the same feel on the interstates going to Carlisle PA), but the trans, not so much.

Anyway, I have found a 81 280ZX 5 speed, so I bought it. Previous searches last year hadn't come up with any success. Not exactly cheap, but I figure I can sell it on DTR.

I'm going to order the 280ZX clutch kit, just wondering if there is anything else I should be aware of besides swapping over the speedo drive gear.

ID numbers for trans

19tooth white gear

Gear ratios. 1981 280ZX had 3.90:1 FD, vs. 3.54:1 for my 75.

Edited July 30, 2024 by HusseinHolland
add pics

[Dave WM]

You are going to need a couple extra bolts for the pressure plate. The throw out bearing collar is a rabbit hole of ideas on what is the correct length. 

[Dave WM]

Oh and I forgot, does the transmission come with the shifter? if not you may need to look into what it takes to make sure the 4 speed will properly engage esp 5th gear IIRC. there is something about it not allowing the 5th detent to fully engage. easy fix with some minor grinding on the bottom of the shifter. Its well covered in this forum. 

[HusseinHolland]

22 minutes ago, Dave WM said:

You are going to need a couple extra bolts for the pressure plate. The throw out bearing collar is a rabbit hole of ideas on what is the correct length. 

Extra bolts? I thought the flywheel is the same - there are additional holes unused in the 280Z install?

19 minutes ago, Dave WM said:

Oh and I forgot, does the transmission come with the shifter? if not you may need to look into what it takes to make sure the 4 speed will properly engage esp 5th gear IIRC. there is something about it not allowing the 5th detent to fully engage. easy fix with some minor grinding on the bottom of the shifter. Its well covered in this forum. 

Thank you for the input.  I ordered a new collar to match the 280ZX clutch kit. 

It does not include the shifter. I will look at the linkage - at a glance the yoke looks the same as my '75. I did read that you need to use the 280Z shifter to get proper operation. EDIT - not finding anything re grinding shifter for 5th engagement - I'll look further.

I'm contemplating 'rebuilding' the trans with new bearings & synchros, since it is a high mileage unit (190K). Not finding much in the way of disassembly directions though, so I may just put it in & see how it feels. Can't be worse than mine.

Edited May 13, 2024 by HusseinHolland

[Yarb]

All of the seals were still available through Nissan. There is a complete parts list posted by @EuroDat on the forum. With @dave wm help he guided me through resealing two close ratio transmissions. Be sure to change all of the seals including the ones in the shifter housing. I have a small amount of parts not many including the main shaft nut I didn’t need. Also the detent springs and ball bearings are still available as well as the speedo seal. Check out @EuroDat. A plethora of information there.

I just took a torch to my shifter and put a small curvature in it to clear 5th gear.

Edited May 13, 2024 by Yarb
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[siteunseen]

Mine wouldn't fully engage 5th because the shift rod hit. You'll see marks where they hit and you grind that down some and it'll go in and stay in 5th.

Post #16

 

[HusseinHolland]

Found Eurodat's parts listing

Shift lever base issue

Ground shifter

 

Edited May 13, 2024 by HusseinHolland

[Zed Head]

I think that the shift lever issue is a 240Z thing.  I had a 78, 81, and 83 5 speed in my 76 at various times.  All used the original 4 speed shifter with no problems.

Also, I think that Dave WM is talkng about the 225mm versus the 240mm clutches.  Different bolt patterns.

The clutch collar needs to match the pressure plate height.  92mm.  The fork pivot is in the same position on all except the very early 4 speeds.

[HusseinHolland]

So, another question - since search doesn't seem to help me find any of the relevant threads ppl have linked for me, is there also  a thread that discusses the disassembly procedure? _ noted that the parts listing indicates one of the nuts is left hand thread, so clearly there is a particular method to the madness required...

[HusseinHolland]

4 minutes ago, Zed Head said:

I think that the shift lever issue is a 240Z thing.  I had a 78, 81, and 83 5 speed in my 76 at various times.  All used the original 4 speed shifter with no problems.

Also, I think that Dave WM is talkng about the 225mm versus the 240mm clutches.  Different bolt patterns.

The clutch collar needs to match the pressure plate height.  92mm.  The fork pivot is in the same position on all except the very early 4 speeds.

Thank you - I'll check the shifter while the trans is out anyway, but good to note that's one less thing to be concerned with. I'm curious whether others found it a requirement to replace bearings on the later 5 speeds, or if they did it to be safe for long term. I'm only going to have this trans in the car a couple of years, so if they (in general) don't manifest bad bearing whine, I'll just look at the state of the fluid that comes out, and look for metal particles that would indicate an issue. Looks like the detent springs & BB's can be easily swapped out, and the input & tail seals.

[Zed Head]

Probably not a "requirement".  Dave WM rebuilt one with completely destroyed adapter plate bearings (the center plate) and it worked fine when finished.  It was still working even with the bad bearings.  The parts seem to be very durable and able to take lots of abuse.  Dave's thread might also be pretty descriptive as far as rebuilding.

@Dave WM

Otherwise, hate to do it to you but ... the FSM has a very thorough rebuild procedure laid out.

Edited May 13, 2024 by Zed Head
+h

[Yarb]

There is a trick to removing the tail shaft as well.