Which is Better 280Z or ZX 5 speed?

[Oiluj]

I did a search and read about 30 different transmission posts and have a question.

It sounds like to 280Z (thru 78) is almost plug-n-play into my late 72 240Z, (just switch-out the speedo gear). The 80-83 280ZX 5 speed requires more modification.

Is the ZX tranny better? I like the idea of a simpler conversion, but is the 280Z tranny have any issues?

Thanks!

[jmortensen]

They both hook right up, no difference there. The real difference is in the ratios. The early 5 speeds have wider ratios and a shorter OD, which makes them more well suited to the 3.54 gears that they came with. This also makes them better suited to the 3.36 gears your 240 came with. The ZX had closer gear ratios and came with a 3.90 rear gear. If you swap the late transmission into a car with a 3.36 the result is a car that is a slug off the line and has a theoretical top speed of 200 mph. Seeing as how most Zs will never break 150, this is a ridiculously tall gear combination in my opinion.

The short version: if you don't want to change the diff, get the 280Z 5 speed. If you want to change the diff and make the car as fast as possible, get a ZX and a lower diff ratio like a 3.90 or 4.11, depending on your intended usage and your motor's power band.

[Oiluj]

Jon,

Thanks! Now I know which tranny to look for...

[turbo 260]

There is another difference. The early 5 speeds had a tendency for a bolt to come loose. The later trannys used a reverse thread that fixed the problem. A third option is the Maxima tranny. The fill plug is on the driver's side, but otherwise the same. It has the wide gearing to get the much heavier Maxima moving, with the better overdrive of the later 280ZX trannys. Also Maximas usually aren't beaten on as much as Zs.

Jim

[soundmasterg]

You could also get a Borg-Warner T5 that came in the Turbo 280ZX's. Its a bit more work to sub that in but some people like them, especially for higher horsepower applications.

greg

[texasz]

One is not really "better" than the other, just different as described above. Check out this little tool, I think it will help you make your decision as well as the info from this forum.

http://www.geocities.com/z_design_studio/

[adamr]

I put in an 83 5spd with an R200 3.90 in my Series One. More involved than on later 240's (my mechanic did it- that's way over my head). I have great low end, and 3rd gear pulls like second. Car moves much faster thru all the gears. It turns well over 3000 rpms at almost 80mph if I remember correctly. I'm not much of a highway driver. I prefer the twisties, and running thru the gears around town, so it's perfect for me.

texasz, great geocite link!

Edited October 13, 2009 by adamr

[=Enigma=]

I remember reading somewhere that the early 5 speeds are basically a re-designed 4 speed with 5th gear sharing the same fork as reverse, and that the fork is prone to breakage resulting in the loss of 5th gear, whereas the later 280ZX tranny is a "true" 5 speed. I'm not sure about the truth in any of this though. Perhaps someone "in the know" can respond with more info on this and set the record straight.

I have an early 5 speed in the car now, and with the stock 3.36 gearing it was a slow dog. The car now has 3.90 in the rear and there's a 280ZX tranny waiting for a rebuild off to the side. I'm hopeful this will wake the old girl up once it's all back together.

[adamr]

I remember reading somewhere that the early 5 speeds are basically a re-designed 4 speed with 5th gear sharing the same fork as reverse, and that the fork is prone to breakage resulting in the loss of 5th gear, whereas the later 280ZX tranny is a "true" 5 speed. I'm not sure about the truth in any of this though. Perhaps someone "in the know" can respond with more info on this and set the record straight.

I have an early 5 speed in the car now, and with the stock 3.36 gearing it was a slow dog. The car now has 3.90 in the rear and there's a 280ZX tranny waiting for a rebuild off to the side. I'm hopeful this will wake the old girl up once it's all back together.

It will wake her up. My name is also Adam, and I too am a Zeeholic!

[doradox]

I remember reading somewhere that the early 5 speeds are basically a re-designed 4 speed with 5th gear sharing the same fork as reverse, and that the fork is prone to breakage resulting in the loss of 5th gear, whereas the later 280ZX tranny is a "true" 5 speed. I'm not sure about the truth in any of this though. Perhaps someone "in the know" can respond with more info on this and set the record straight.

I have an early 5 speed in the car now, and with the stock 3.36 gearing it was a slow dog. The car now has 3.90 in the rear and there's a 280ZX tranny waiting for a rebuild off to the side. I'm hopeful this will wake the old girl up once it's all back together.

Typically if 5th and reverse share the same gate they share the same shift fork. Most OD 5 speeds follow this config. There are exceptions though.

Steve

[Oiluj]

I got a 77 5-speed locally for my 72' 240z a few weeks ago. Plan to get it rebuilt and install it sometime next year.

Should be better for highway gas mileage on longer runs, but about the same for around town. Perfect!