Seized 4 speed

[mbarjbar]

Well, today was the day, after 14 years, I fired up my 1970 Z. All seemed well until after about 20 miles, the tranny started whining as I shifted. I nursed her home to within 50 yards of my house when the tranny seized and locked the rear wheels! That was fun!! After all the time and money spent on Z-Therapy carbs, all new hydraulic, rotors, brakes, etc., I had not checked the tranny oils level. So, I see this as an opportunity--conversion to 5-speed. Can anyone guide me as to what year of 5 speed will bolt up, potential problems, cost estimates, and good sources.

Thanks,

Mike

[Arne]

This has been covered so many times that its far past funny. The problem is that the search terms are so generic that it's very hard to find the info.

Short version - any 5 speed from any 280Z or 280ZX will bolt up to your engine and into the car. For simplicity, you will want to use the clutch fork and the release bearing from your four speed. The driveshaft and rear mount from the four speed should be used as well.

But if your car is a '70 or '71 - unless you happen to find a Type A five speed (rare, never factory installed in the USA), you will either need to enlarge the opening in the tunnel and console for the shift lever, or the shift lever from the five speed will need to be modified (cut, welded and bent). Your current four speed lever won't fit at all.

If you do happen to find a Type A, you will need the driveshaft that came with it instead of your original one.

[mbarjbar]

Arne,

Yes, the search thing did not do me much good. Your comments are very helpful. Sounds like a bolt on except you cannot shift....:-( What is involved with enlarging the opening in the tunnel and console?

Thanks, Mike

[Pleiner87]

Ouch, well that does give you reason to upgrade to the 5-speed... As for what 5-speed will bolt up, on my dads '74 260, he went from a 3-speed automatic to a 1978 280Z 5-speed. Here in Missouri we have a guy called "The Z Man" who runs a Z grave yard (around 100 z cars and barns full of parts) he did the converson. From what he said any trany from '70-'83 should work (240-280zx) I think he said something about the turbo 280zx tranys not working though. As for what is needed for the swap, you should be good allready having a manual in it, should just need the 5-speed. If you can find a "Z man" in your area you can pick one up there or look on creigslist for a tranny. I'll see if my dad can remember what he payed for the 5-speed, i think it was somewhere in the $100 range. So far no problems with the swap, except the trany pops out of 4th (it's the trans, not the shifter opening) good luck, Todd

Edited January 28, 2009 by Pleiner87

[Arne]

Arne,

Yes, the search thing did not do me much good. Your comments are very helpful. Sounds like a bolt on except you cannot shift....:-( What is involved with enlarging the opening in the tunnel and console?

Thanks, Mike

Since I've never done it myself, I can't speak from experience. But the shift mechanism is located farther forward on all of the '72 and later transmissions. So the hole needs to be enlarged at the front, by about an inch or so, I believe.

Myself, I'd rather modify a later shift lever than cut my car. Check out this thread for a picture, part way down the page.

http://www.classiczcars.com/forums/showthread.php?t=24759&page=3

Or here's a picture of a different way to do it. CM had problems with this one breaking until they gusseted the hell out of it.

http://classicmotorsports.net/project-cars/1970-datsun-240z/digging-datsun-details/

BTW, the previous post did have a good comment I missed. The later ZX turbos came with a Borg Warner T5 transmission. Installing that one is a lot different. Stick with the non-turbos for simplicity.

[Weasel73240Z]

I just finished the 5 speed swap with a 4.11 R180 into my 240. Everything was strictly bolt-up, I used a 5-speed out of a 1979 280ZX. I did use my original driveshaft, tranny mounts, clutch fork and clutch master cylinder. I didn't have to open up the tranny hole, but I think the 73 doesn't have that clearance problem that the 70 has.

I had to modify the speedo cog sleeve in the new tranny, but that was because I swapped out the rear end. If your keeping the rear diff./gear ratio you shouldn't have to change the speedo cog.

The tranny swap itself is 100% bolt-up, at least in my experience. BTW, my understanding is the ZX turbo trannys are the BW's, and they take some fabrication to work. Stick to a (NA) 1979 - 1883 280ZX and you should have no problems.

For reference, I paid $250 for the 5 speed. I think they can be had cheaper in other parts of the country where they are easier to find. Took me a few weeks to locate one here in MA.

[mbarjbar]

Thanks guys for some great comments. I was thinking to go the quick route and just get another 4-speed, but for a little more money and effort, I would have that 5th gear. I went to an overdrive in my 1971 MGB and it made a world of difference at freeway speeds.

Mike

[Arne]

I was thinking to go the quick route and just get another 4-speed...

Bear in mind that the exact same shifter issues apply with most 4 speeds as well. You'd need to find one from a '70 or '71 to go in without mods. A '72 or later 4 speed still requires the same shifter mods as a five speed.

As it happens, I do have a spare known good early 4 speed here in Oregon.

[mbarjbar]

I have a line on a '83 5 speed with 1 year warranty ($495) and a local 4 speed ($120). Not sure what year of 4 speed. I want to replace the clutch when I make the swap, do I buy a clutch that fits the tranny year or the of my car, 1970? Thanks for the help!

Mike

[Arne]

You need to by a clutch that matches the year of the release bearing collar that you end up using. Since the used transmission may or may not come with the collar, the simplest way to ensure that it all works is for you to use the release bearing collar from the bad transmission and then buy the clutch for the year of the car.

[Walter Moore]

If you end up cutting the floor to allow the shifter to work, you will also have to go to the later inner shift boot. The original style boot will not seal properly in the larger hole, and will bind up when you try to use 3rd or 5th gear.

You can buy them a lot of places, but just so you understand what I am talking about here is an example:

http://www.courtesyparts.com/shift-boot-240z-260z-280z-280zx-m/t-p-568965.html?cPath=7724_7755&

You only need to cut out about 1 inch if I remember correctly. I didn't actually cut my floor personally, the P.O. had installed a later 4 speed before I bought the car, and when it failed I went with a 5 speed from an 83 ZX.

I still have my original differential, but eventually I suspect I will put a numerically higher ratio unit in the car because the ZX transmission is poorly matched to the 3.36:1 differential. That is another thread entirely.

[mbarjbar]

You guys are great! Thanks so much for the help. What do you think about the cost of the 5 speed? BTW, plus about $130 in shipping. The 4 speed was from a '73:-(

Mike