Speedo gear not meshing properly

[drcomanche]

As the title states, the gear isn't aligning properly. Its an np231, the gear is a 40 tooth gear. The top "holder" is aligned for 39 to 45 teeth. I installed it and just moved the input shaft back and forth a bit to test and when reversing, it pops as though its not turning properly. When going forwards it kind of lines up, popping every 5 or 6 rotations. The inner shaft gear isn't damaged in any way, but when i pulled the speed gear out, you could see that it had bent portions of it. Probably worth noting that my previous 39 tooth gear, while it did function, was worn severely at an angle, to where it was almost flat on one side. Again, it still worked when driving, but that doesn't seem to be how its intended to function. I've seen people pull them out with no wear at all. Is there something I'm missing with alignment? Or is it normal to chunk the gears up a bit?

[ghetdjc320]

It should be plenty smooth. Are you sure you have it aligned properly? It’s always a bit tricky since it does not align with the hold down bolt but rather with a ridge near the bottom of the tail cone. If you 100% sure there isn’t anything wrong with the alignment then take a picture of your tail shaft speedo splines and look for damage. Also check your speedo gear sending unit for runout when turning the speedo gear 

[drcomanche]

16 hours ago, ghetdjc320 said:

It should be plenty smooth. Are you sure you have it aligned properly? It’s always a bit tricky since it does not align with the hold down bolt but rather with a ridge near the bottom of the tail cone. If you 100% sure there isn’t anything wrong with the alignment then take a picture of your tail shaft speedo splines and look for damage. Also check your speedo gear sending unit for runout when turning the speedo gear 

I'm not lining the indicator up with the bolt, although there is no ridge or dimple to mark it with, I was relying on looking up pics and that there's only 4 orientations it could be. I had another look at the shaft gear, still looks perfect. Hard to see, but there it is. I was also thinking, is this supposed to be a short shaft assembly and maybe its reaching too far? You can see a groove at the bottom of the plate in the pic from it.

 

[ghetdjc320]

49 minutes ago, drcomanche said:

I'm not lining the indicator up with the bolt, although there is no ridge or dimple to mark it with, I was relying on looking up pics and that there's only 4 orientations it could be. I had another look at the shaft gear, still looks perfect. Hard to see, but there it is. I was also thinking, is this supposed to be a short shaft assembly and maybe its reaching too far? You can see a groove at the bottom of the plate in the pic from it.

 

 

the long and short speed gears are actually both compatible with the tail housing. Only the sending units are different. Your sye tailshaft probably has a plastic gear held in with a couple of snap rings. Try removing that tail cone and inspecting that plastic gear up close. Also make sure the gear has both rings in place and can’t move around

[drcomanche]

Popped the tail cone off yesterday to have a look. The gear on the shaft is nice and secure with minimal wear. I was playing with the gear and the tailcone seeing how it fit up and I think i found my problem. The snap ring holding the output shaft bearing was in the gears, hold them from moving. I'm guessing that the gap in the snap ring needs to be right where the gear sits for it to clear properly. 

 

[ghetdjc320]

That speedo gear is not clocked properly. Turn it until it fits correctly. The snap ring should never interfere with the speedo gear. That’s a strange tail housing that doesn’t have a fully machined groove for the snap ring all the way around! Do you know what kit that is? 

[ghetdjc320]

This is where your mark should align:

 

[drcomanche]

14 hours ago, ghetdjc320 said:

That speedo gear is not clocked properly. Turn it until it fits correctly. The snap ring should never interfere with the speedo gear. That’s a strange tail housing that doesn’t have a fully machined groove for the snap ring all the way around! Do you know what kit that is? 

Thats exactly where it was aligned. I wasn't matching it with the retaining bolt. At that exact alignment, it contacts the snap ring, which when I replace the bearing, will be oriented with the gap facing the gear. It's a slip yoke eliminator kit from teraflex, I believe. It's one of the older versions so it may not be their up to date best design. When I took out the snap ring, it moved fine.

[ghetdjc320]

20 hours ago, drcomanche said:

Thats exactly where it was aligned. I wasn't matching it with the retaining bolt. At that exact alignment, it contacts the snap ring, which when I replace the bearing, will be oriented with the gap facing the gear. It's a slip yoke eliminator kit from teraflex, I believe. It's one of the older versions so it may not be their up to date best design. When I took out the snap ring, it moved fine.

Very odd. Will the snap ring stay in place and not spin at all in the housing? If not, use some green loctite to fix it in place and let it cure before reinstalling

[drcomanche]

1 hour ago, ghetdjc320 said:

Very odd. Will the snap ring stay in place and not spin at all in the housing? If not, use some green loctite to fix it in place and let it cure before reinstalling

It is VERY tight in there. It was a chore to remove and while it was in, I couldn't get it to budge at all.

[drcomanche]

4 hours ago, saveevryjp1998 said:

I'd send Teraflex tech support an email. I'm sure you'll get some help. Fyi, if the bearing is that tight, you repress it to move the clip to spin freely, you'd still have the chance of it moving to cause an issue. I wouldn't be convinced that is a solution and rule that out.

I put in the new bearing and the c clip, then mocked it up with the gear in. It all works fine. Its amazing how that little tolerance changed everything. The tightness of the c clip wasn't because it was up against the bearing, it's just a really hardy c clip thats own tension holds it in place. I am unable to move it when it is in. I'll take more of a look at it and see if there's something I'm not seeing. I am concerned that it would move through vibration or friction.