speedometer drive gears...

[truknut]

I've started working on my '28 AR again, and I could use some help with the speedo drive gears. I have the gear that goes into the screw in piece, that has 32 x 6 stamped on it. The gear that slides onto the splined shaft has 5.17 stamped on it. I cannot get the two gears to mesh correctly, and I think there must be a spacer that belongs between the bearing, and the gear, as there is about .500 end play between the gear and the snap ring groove. I do not have the correct snap ring either, hopefully, someone has a spare for sale. Neil was kind enough to offer some advice a couple years ago, but I am still baffled. Is there something missing from my set up? I was told there was no thrust washer on the early '28s. Maybe something else goes after the bearing? I evidently need AA17286 speedo drive gear retainer. I appreciate any suggestions.

Rick

[spectria]

I've started working on my '28 AR again, and I could use some help with the speedo drive gears. I have the gear that goes into the screw in piece, that has 32 x 6 stamped on it. The gear that slides onto the splined shaft has 5.17 stamped on it. I cannot get the two gears to mesh correctly, and I think there must be a spacer that belongs between the bearing, and the gear, as there is about .500 end play between the gear and the snap ring groove. I do not have the correct snap ring either, hopefully, someone has a spare for sale. Neil was kind enough to offer some advice a couple years ago, but I am still baffled. Is there something missing from my set up? I was told there was no thrust washer on the early '28s. Maybe something else goes after the bearing? I evidently need AA17286 speedo drive gear retainer. I appreciate any suggestions
Rick

Did you mean a 1/2 inch of play?

[Brian T]

Hello Rick,
I remember you posting about this last year, when I had my transmission out earlier this year I noticed the same condition, the end play in the driven gear is between the driveshaft bearing and the end of the u-joint (1/4 inch or less ) when the rear axle is installed, not the snap ring.
The snap ring serves no purpose except to keep the driven gear from falling off when the axles were on the assemby line hanging with the drive shaft pointing down, on there way to the main assemby area.
Apparently it does not need a spacer, the driven gear will not be dead center on the drive gear but will make proper contact, mine worked OK before and after, I have pics to send you if you want, hope this helps.

[truknut]

Hi, Brian, please forward pics. Glad to hear someone else has seen this problem. I still don't understand why the two gears won't mesh correctly. Thanks, Rick

[Brian T]

Rick here are the pics,
In the one picture inside the torque tube shows the drive gear on the shaft is pushed back wards to the drive shaft bearing, (if the axle were installed) the gear would only move forward around a 1/4 inch where it will contact the end of the u-joint, in that case the driven gear will be centered.

The other pic shows where the position of the 2 gears would be if the drive gear were in the rearward position, they still have proper contact and will not ride off the end, (Is this what you meant by not meshing correct?).

It does make sense that there should be a spacer. however there was no problem before removal and none after, you would also think that the drive shaft bearing would have moved part way out of the race, I saw no indication that it had done so.

[truknut]

Hi, Brian, thanx for the pics. I see what you are saying about the mesh not changing no matter if the driven gear is forward or back. It appears that when I screw the other gear in, it wants to bind, and not mesh properly. It just jams, maybe I need to oil everything a bit first, to aid in meshing. The parts are lightly oiled, maybe too light? Thanks, Rick

[Brian T]

Hello Rick,
Maybe you have a mismatched set of speedo gears, post a pic of them or just the numbers from them, I assume you have the worm drive axle?, and the high - low unit, from what I understand the spacer you spoke of was not used with the above axle, its difficult to say whats been done to these trucks over the years.

[Bob C]

Like Brian said I would count the teeth on both gears and make sure they are a match.
This link has some pictures of the different gears http://forums.aa-fords.com/viewtopic.ph ... meter+gear

Bob

[truknut]

one gear has 32 x 6, and 5 1/6 1, the gear that goes on the drive shaft has 5.17. No other markings are visible.


Rick

[Brian T]

Hello Rick ----- Disregard this post, I hit the submit button before finishing and could not delete.

Well you have the correct speedo gears, the ID numbers are the same as the ones in my truck and the same as a spare set I have, the only other possibility is that the drive shaft as dropped down enough to cause a bind as the driven gear tucks under the drive gear, which is what you maybe describing as not meshing.
If the axle is not attached to the trans try raising the shaft upward, if it is installed then have someone turn both rear wheels at the same time as you install the gear.

[Brian T]

Hello Rick,
Well you have the correct speedo gears, the ID numbers are the same as the ones in my truck and the same as a spare set I have, the only other possibility is that the drive shaft as dropped down enough to cause a bind as the driven gear tucks (UNDER) the drive gear, which is what you maybe describing as not meshing.
If the axle is not attached to the trans try raising the shaft upward, if it is installed then have someone turn both rear wheels so the drive shaft turns at the same time as you install the gear.

[truknut]

MERRY CHRISTMAS, everyone!