Speedo gear body doesn't push in all the way

[PKD]

I am having problems pushing speedo gear body back into back into the gear housing in the back of the 5 spd tranny on my 76 280z. I replaced the cable with a new one because the former owner decided to hook a laptop to an electronic gear body that didn't work the mechanical speedo. The speedometer is the original to the car and requires a cable. The transmission was a swap from a 82 ZX. The former owner did, however furnish me with a correct speedo gear/body that came off this tranny.  I put the two bodies and gears side by side and noticed no difference in the gear body and gear. The slot is on the correct side of the offset. The problem is that the electronic gear body pushes in farther into the hole where the gear drive is then the mechanical body. I did confirm that when the rear wheel rotates, the cable end was rotating properly but the body wasn't as deep as the electronic body. I took the car around the block on a test drive and noticed the speedo bounces a little but is accurate. How do I get that body further into the housing? Is there a trick, more force? I don't want to damage anything as it is a real pain to get correct spares.

[EuroDat]

If I understand this correctly, you have a speedo gear, gear adaptor and cable from the original 280Z transmission and now you want to fit it to the ZX transmission.

It sounds like you have an adaptor that should face upwards with the slot and bolt at the top, but the transmission has the bolt under the adaptor. See photo. Therefore you have rotated the adaptor 180 degrees to fit it.

 

To solve this problem, you need to machine or file a slot in the opposite side so you can rotate the adaptor 180 degrees.

This problem occurs when you do the transmission upgrade from a 240SX with electirc speedo to a 240Z or 280Z with manual cable version.

It should be easy to correct if that is your problem. Goodluck.

[EuroDat]

 

 

[PKD]

9 hours ago, EuroDat said:

If I understand this correctly, you have a speedo gear, gear adaptor and cable from the original 280Z transmission and now you want to fit it to the ZX transmission.

It sounds like you have an adaptor that should face upwards with the slot and bolt at the top, but the transmission has the bolt under the adaptor. See photo. Therefore you have rotated the adaptor 180 degrees to fit it.

 

To solve this problem, you need to machine or file a slot in the opposite side so you can rotate the adaptor 180 degrees.

This problem occurs when you do the transmission upgrade from a 240SX with electirc speedo to a 240Z or 280Z with manual cable version.

 

It should be easy to correct if that is your problem. Goodluck.

I did see this earlier online. I had checked the offset right away and found that the electronic and the cable type are identical in offset. I had rotated 180 several times. The problem is that the unit, no matter what, will not sink into proper position. It sits out slightly. The adapter bolt and washer are not flush on the side of the tranny like the electronic one did. It is literally sticking out. Is there a way of pushing this in properly. Is there a trick that I am missing to get it to push in flush with the side of the tranny so the bolt is flush.

 

[Zed Head]

You might try removing the o-ring, and giving the outside of the sleeve a light sanding, removing any burrs.  Then apply some oil and see if it will slide in to the proper depth.  Without the o-ring it will be more apparent if the problem is a hard stop or a tight fit.  If it goes in all the way you can put the o-ring back on and be confident in pressing it in.

Typically, when I've removed these from old transmission, they always require a pair of large pliers and some twisting and pulling.  They're normally a tight fit.  If you looked at 10 of those on 10 old transmissions, 5 of them would probably have plier teeth marks on them.

[PKD]

36 minutes ago, Zed Head said:

You might try removing the o-ring, and giving the outside of the sleeve a light sanding, removing any burrs.  Then apply some oil and see if it will slide in to the proper depth.  Without the o-ring it will be more apparent if the problem is a hard stop or a tight fit.  If it goes in all the way you can put the o-ring back on and be confident in pressing it in.

Typically, when I've removed these from old transmission, they always require a pair of large pliers and some twisting and pulling.  They're normally a tight fit.  If you looked at 10 of those on 10 old transmissions, 5 of them would probably have plier teeth marks on them.

Thanks Zed,

I believe this might answer the question. I will have to give it a try this week. I'll let you know what happens.

[sweatybetty]

if it works and doesnt leak, maybe it is the way it should be.

[EuroDat]

That would be my next move. See if it fits without the o-ring. If that works, then buy a new o-ring and try it again.

Is the o-ring new? The o-ring can swell up andmake it very have to fit.

Other things to try:

1. See if it goes all the way in without the speedo gearin theadapter. Just the adapter.

2. Can you check the gear height with the electric unit. Top of the gear to the slot for the locating tab/bolt. It could be to high and bottoming out against the other side of the transmission. The gear sits in the adaptor. The clearence to the other side of the transmission stops it from coming out. That clearance could be too small.

You can check this by putting a small dab of play doe on the end then installing it. Remove it and check if the play doe shows any sign of contact.

[7tooZ]

I agree with Zed. I ran into the same issue and did what he is suggesting. I used emery cloth strip to smooth out the surfaced until it slid in with light pressure.


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[PKD]

Thanks all for the good suggestions. Zed's suggestion worked. It actually was in a bit better after the run around the block. I took the screw out and gave the unit a slight tap with a screwdriver in the slot and viola it went right in. I did take off the cable and check the end to make sure it was in correctly. It was but I put it back together with a little more snug. The test drive was a success. The speedo did bounce a little below 40mph then smoothed out. I don't know if that is typical for these cars? We saw no bounce or wiggle past 40 to 55. The speedo gear body might just be old. The cable is new and when I installed it to the speedometer, I ran a drill on it to see if it was working ok and it was super smooth. So my only suspect is that gear body must have a hang point in it that is detectable at slow speeds.