NP218 - Speedometer Gear Installation Help

[Mogman]

I haven’t replaced any parts. Everything is the same. I agree that it makes absolutely zero sense.
With that said, I did partially disassemble and grease the 90° adapter. But there isn’t really anyway that could be put together incorrectly since it is also gear driven and has pockets for all the spinning parts to properly fit into. Seems like it would be pretty hard to assemble incorrectly.
I am really scratching my head on this one. Never seen anything like it.

—-
Ref, what should I be checking on the 90?

Check the direction, looking towards the speedo the cable should be turning counter clockwise, so looking at the adapter output it should be turning clockwise

 

[Mogman]

So if you turn the input counter clockwise the output should turn clockwise.

 

[mgFray]

ok... I have found the issue... There is another marking (see pictures). I assume that, like me, you have the orange 35 tooth speedo drive gear. if that is the case, you will see another marking on the opposite side of the orifice. now, that being said, I put mine to that setting and everything went smoothly. I got in to give it a quick test drive... problem. When I backup, the speedo runs as does the odometer. when I go forward, the speedo does not run and the odometer runs backwards (subtracting mileage). there are not enough walls to bang my head against. I guess progress is a good thing... though I just want it to work right. anyone have any suggestions?View attachment 925052

I won't be home until this weekend, but I'll definitely look for that. From what I saw on the mirror, I just have a lot of dirt up there, but it may very well be under the dirt and maybe that will fix it?!

I'll let you know when I can get in there to attempt that.

 

[GYs_M998]

-If I spin the speedo cable from the T-case side, it needs to spin counter clockwise to simulate moving forward.
-looking at the output from the speedo pinion on the t-case, it spins counter clockwise as you look at it.

These two are opposite. So this means the gear is spinning the wrong way. But how is that even possible?

The 90° adapter: if I look at the input and spin it clockwise, and look at the output as it is being spun clockwise on the input, it too spins clockwise. There really isn’t any other possible way the 90° could work.

 

[Mogman]

As I said looking towards the speedo it needs to turn counter clockwise, so looking towards the t case it would be turning clockwise.
So if you spin the input to the adapter counter clockwise, you are looking towards the speedo then the output would need to turn clockwise as you are now looking towards the t case.
It sounds like you have the wrong 90 deg adapter.

 

[GYs_M998]

I can assure you that this exact setup worked properly for the previous 7 years I’ve owned this truck. It worked until I took out the Speedo pinion gear to test something else a while back. It’s been out for longer than expected (several months), but nothing else has been changed. This is the same adapter unless someone crawled under my truck in a parking lot and swapped it out for a different one while I was getting a hotdog and a big gulp. Same pinion gear. Same speedo. Same cable. Same everything. But somehow, it is now inexplicably working reverse to what it should be. As far as I can figure, nothing short of putting the pinion gear on the opposite side of the output shaft of the TCase will case it to run in reverse. So this situation I am in makes no sense to logical thinkers and I am pulling my hair out because of it. I am sure there is a simple answer to remedy this- something I have done incorrectly. I just can’t see what.

I have attached a drill to the speedo cable to confirm that the speedo functions properly when the cable is spun counterclockwise.

in the pics [of my actual parts] below I have drawn some arrows to illustrate what is happening (since we cannot upload videos). The speedo cable is being driven counter clockwise when the truck is in reverse. I know this to be fact because I had a camera on the bare pinion chuck as I rolled the truck backwards. Follow the blue arrows in both pics to get a visual of what I saw in that video. The pic of the chuck is a screen grab from the video I took to see what direction it was spinning; I had a very clear view of the direction it was spinning.

I appreciate the help and ideas. I am willing to try anything at this point. Thank you for going down this whimsical rabbit hole with me.

 

[Mogman]

That is a very strange problem, but this is not the first time I have heard someone having this issue, I do not remember seeing a resolution though.
Coming out of the TC it is correct, coming out of the adapter it is backwards, weird

 

[REF]

Its been a long time since I had the 90 deg adapter apart, But I seem to remember that you can put it together in a way that reverses the rotation.
Your cable may be long enough to hook directly to the TC just to make sure that corrects the problem.

Edit: I think you can remove the output housing and trade it with the cap on the opposite side, but it's been a long time and doing my best to remember.

 

[GYs_M998]

Its been a long time since I had the 90 deg adapter apart, But I seem to remember that you can put it together in a way that reverses the rotation.
Your cable may be long enough to hook directly to the TC just to make sure that corrects the problem.

Edit: I think you can remove the output housing and trade it with the cap on the opposite side, but it's been a long time and doing my best to remember.

REF,
You’re the man. You got my hamster back on the wheel. At some point long ago I must have COMPLETELY disassembled the 90° adapter and put it back together incorrectly- or maybe even my brother or my son did it since we were all fiddling with it at one point or another. For life of me I don’t remember ever disassembling this thing, but one of us must have. If you ever hear of this problem again, the fix is to swap the end cap and the output lug. Boom, rotation corrected. I had no idea the end cap side and the output side were the same thread or even the same size. I thought it was just an inspection/lube point. Go figure. I’ll remember this one for years to come.

if you look at the two photos that are similar, you will spot the difference

Thank you mogman and ref for your help. You have saved me from some more sleepless nights…. Until the next weird problem.

 

[mgFray]

Finding and then lining up the 32-35 mark and now I’ve got the gear working again. Thanks!

Unfortunately I still have that stupid bouncing speedo needle.. I pulled out the cable, lubed it lightly and put it back in, less of a bounce, but there is still a noticeable bounce. I guess my next step is to release the various hold down points and see if maybe one of them is pinching it. Finally feels like I almost have it working the “right way” again.

 

[GYs_M998]

Finding and then lining up the 32-35 mark and now I’ve got the gear working again. Thanks!

Unfortunately I still have that stupid bouncing speedo needle.. I pulled out the cable, lubed it lightly and put it back in, less of a bounce, but there is still a noticeable bounce. I guess my next step is to release the various hold down points and see if maybe one of them is pinching it. Finally feels like I almost have it working the “right way” again.

Could be that.
Or maybe you have a bend in it with a radius that is too small.
My recommendation would be to get it as straight as you can in the truck without taking it out, loosen all the hold downs, and see if it spins freely. If it does, it’s one of those two issues. If it does not, you may have another issue inside the cable.

 

[Mogman]

Finding and then lining up the 32-35 mark and now I’ve got the gear working again. Thanks!

Unfortunately I still have that stupid bouncing speedo needle.. I pulled out the cable, lubed it lightly and put it back in, less of a bounce, but there is still a noticeable bounce. I guess my next step is to release the various hold down points and see if maybe one of them is pinching it. Finally feels like I almost have it working the “right way” again.

It is also possible it is the speedo itself, less likely since it got better with lubrication, I use good ol axle grease and have for 50 years