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280zx 5 Speed Won't Reverse


Muzez

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Found a local 280zx 5 speed trans out of a 1980 NA 280zx. Trans moves pretty easily through 1 to 5, but I can't get it into reverse. Still installed in car, but car is not operational so I can't test it. Owner has no history, picked it up as a parts car. 

Is there any safety device in the older Zs which would prevent the car from going into reverse like a collar or a sensor?

Worth buying to rebuild knowing that reverse is currently not functioning or best to run away? Price is $100. 

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3 hours ago, siteunseen said:

My 280zx wide transmission's shifter hit in my 240. If you take the shift rod out you can see the nicks if it's hitting

@siteunseen Good suggestion. I pulled the shifter before I left and it looks like there isn’t any damage. It’s actually less grimy than the shifter currently installed on the 280z 5 speed that I had planned to rebuild this winter so I grabbed it haha. (Photos below)

Will pick up the ZX trans this weekend.

@Zed Head the boot and center console were already missing so I could see the shifter area though I didn’t check to see if anything was blocking the shifter. It felt like I couldn’t find reverse. Where I should be able to push right and down, I couldn’t feel the slot. When I would push over from 5th to R, it would slide back into 4th.

 

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4E4882A1-2A65-4B26-9A9A-0826AB7955AB.jpeg

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First gear is 3.321 in the Z and 3.062 in the ZX.  The ZX is usually paired with a 3.9 diff, the Z a 3.54.
@Zed Head I always learn new things from you. Always assumed R200 was synonymous with 3.9. Didn't realize that the diff internals would be different based on 280z/280zx. Thanks!

Sent from my ONEPLUS A3000 using Tapatalk

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you should NOT be able to go from 5th to reverse, the reverse lockout mech prevent that. You have to shift into some other gear (besides reverse) to clear the mech then you can go into reverse.
That explains it! Thanks as usual Dave!
@siteunseen thanks for the share. Reading through now.

It's great having you guys around because a lot of the older posts link to images on Geosites which are no longer active. Great to have all of the knowledge. Always appreciated guys!

Sent from my ONEPLUS A3000 using Tapatalk

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17 hours ago, Muzez said:

 It felt like I couldn’t find reverse. Where I should be able to push right and down, I couldn’t feel the slot.

Good catch by Dave, but have you gone back and tried again?  You suggested that you had already tried the proper shifting motion, above.  Right and down.

Just saying...

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1 hour ago, Zed Head said:

Good catch by Dave, but have you gone back and tried again?  You suggested that you had already tried the proper shifting motion, above.  Right and down.

Just saying...

Haven't yet. Going tomorrow. My wife usually tries to limit garage time to one day a weekend. Otherwise "She would never see me".

Gonna sneak over tomorrow morning while I am running some errands. I was kinda thinking I going to pull it either way though even if I can't get it into reverse. I have wanted to learn to rebuild a trans for a while. Best case scenario, I have a working trans I can use or sell. Worst case scenario, I take it apart, find it was junk and I am out $100. I have spent money on stupider things haha :)

 

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@Dave WM  knows about reverse problems, he has some parts, and has worked on trashed transmissions.  They are surprisingly durable.  Reverse is a simple mechanism and can be reached from the backside of the adapter plate.  Shouldn't have to remove the front case although that would let you inspect the synchros and gears. 

If the drainplug is in it see if it has metal stuck on it.  Most yards drain the fluids though before they put them out so it might have been wiped already.

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Second to reverse usually works well. With it turning would be the best, but as you mentioned it was still in the car so that won't be an option. 

$100 is a good price. Pick and Pull is $105.00 when they have one but wants a core. I got mine at another yard for $85.00 + core I gave them an old automatic. 

 

 

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assuming its not a reverse lockout mechanism issue, then as Zed Head mentioned earlier it could be you just need to rotate either the input or the output shaft. The reverses is not sychromesh that is they are not always engaged like the rest of the gears (which rely on selecting the gears you want to use with locking hubs). Its more of a "crash box" style system where the gears are literally engaged to a reverse idler by moving the entire gear cluster. they are straight cut gears with bevels on the sides that slip together. that being said sometimes the bevel will exactly line up preventing the meshing of the gear teeth. Generally this is not a problem in a installed system as the slightest movement of the gears will clear the jam (just clutch in and try again, with the engine running the drag in the gears will move them the tiny bit needed to clear the contact point of the bevels).

IF moving input or output shaft does not clear the issue, then I suppose it would be worth trying unbolting the reverse lockout mechanism from the side (two small 10mm bolts holding on diamond shape cover) on the outside chance that something has malfunctioned and is not allowing it to work as designed and is keeping you from going into reverse. The way it works is when you shift into 5th it trips a lever (any other gear will not trip the lever). shifting from 5th back to any other gear (beside reverse) clears the tripped lever. the idea is since 5th and rev share the same shift fork, you could with out this protection easily shift from 5th into reverse (perhaps forgetting what gear you are in and trying for a 3/4 shift when your are actually in 5 causing the potential for a 5/R shift.. disaster....

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31 minutes ago, siteunseen said:

You won the election but now your 4 years begins. LOL

 

True life. Was looking at the drain plug and filler plug are stripped. 😞 good news is that I am able to get it into reverse. It’s a little more difficult than other gears, but it will go. Will take it apart this week and post more photos 

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And a free throwout bearing and sleeve!  Looks like a Z shifter, not a ZX.  Is that yours?

Hope they knew what they were doing, it's been worked on.  I'd file some new flats on the fill plug, clean up the area around the threads and squirt some penetrant on there.  Then hit it with a torch or heat gun before trying to remove it, and the drain plug.  Do it while it's together, it's hard to generate leverage when the cases are off.

Who paints their transmission red?

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1 minute ago, Zed Head said:

And a free throwout bearing and sleeve!  Looks like a Z shifter, not a ZX.  Is that yours?

Hope they knew what they were doing, it's been worked on.  I'd file some new flats on the fill plug, clean up the area around the threads and squirt some penetrant on there.  Then hit it with a torch or heat gun before trying to remove it, and the drain plug.  Do it while it's together, it's hard to generate leverage when the cases are off.

Who paints their transmission red?

@Zed HeadThat is the shifter that was in it. Was surprised by that too. Looks like newer seals on the tail shaft which is promising. Though some jerk broke the front windshield of the car since last visit and there is a bunch of glass in the shifter area that I am hoping didn’t get inside.

And good advice on the prep steps for removing the fill plug. What’s the nuclear option if that doesn’t work? Left handed bit? 

Also, agreed re: Red paint. They didn’t do anything special anywhere else on the car except that. Wish they had applied the same care to the differential though, it was rusted something aweful. 

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I found that these wobble head extensions, 1/2", get a good bite in the drain plug hole.  It's a tough one.  Once they get wallowed out it gets messy.

This is the Harbor Freight version for an impact driver.  No chrome helps it get a bite also.

https://www.harborfreight.com/3-piece-1-2-half-inch-drive-impact-wobble-socket-extension-set-67066.html

image.png

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Heat is your friend!

Don't make it any worse. Big breaker bar. I probably wouldnt ever resort to LH drill bits. The problem would be getting whats left out of the case without damaging the soft aluminum. Might weld to it as a last resort.

I have used a monkey wrench as a nuclear option in the past but that pretty much destroys the fill plug

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