Transmission woes...

[Talkwrench]

1. So I finally assembled the trans after smashing some teeth off the cluster, thought I'll get it right and also ordered a NOS second gear etc. So all 'seems' ok, been for a few runs. I thought to myself I have another case and about 80% of parts to build another "spare - ready to go" trans . I knew when I had the gear that the profile of it was slightly different [ see pic] but just thought it was a different manufacturer - updated perhaps. Well I had to do a reference in Macs book and theres a paragraph on the gear and its a later one and from what I read its not interchangeable as there a slight difference in angle, However there doesn't seem to be an issue , no noise, no difficulty getting in and out of gear, doesn't jump out. Anyone else done this?- do I worry ???

2. The pin on the shaft has been smashed- worn off, are these available and is there any tricks for removal and replace?

3. The Syncro hub I have slides on easy and there's the slightest of movement on the shaft, whats acceptable?

[Juergen]

Looks like the gear on the shaft is the "pointy tooth" model used in the 1950 up early style trans. Since the angle is different from the earlier matching cluster , the teeth will only make contact on only a small part of the teeth, making it weaker.

The sheared pin is not hardened and can be drilled out with a 1/8 inch drill bit and then be replaced with an 1/8 inch pin (or cut off a 1/8 inch bit to fit). It can be held in place with a dab of JB Weld.

[rotorwrench]

The diamond gears were introduced in 1951 in 259 series transmissions. I believe that the angles are different enough to affect contact pattern and likely would be noisy if they work at all. I wouldn't recommend using them with the older gears. The F1 top shift transmissions of 1951 & 52 had special gears that will only work well as a set.

The pin in the main shaft should have a little spring under it. These types lock the second gear on the shaft. Not all main shafts have this feature. Those that do require the second gear that has the hole in it so that the pin can be pushed through the hole or it won't come off.

[Kurt in NJ]

I put a later cluster in my 46 many years ago,the teeth had a different shape and there was one less on the cluster— was desperate— no noise and it survived a lot of abuse I didn’t know that it wouldn’t work.

[1952henry]

^^^^thats the wonderful thing about the internet. You know now what worked years ago doesn’t work now.

[Terry,OH]

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The pin in the shaft does not need to be glued in place since it can not come out when assembled. It is easy to drill too deeply when removing the old pin (mild steel) so use some care. If the 2nd gear fits loose on the shaft, check the shaft diameter for wear if it is within spec the bushing in the 2nd gear is most likely worn and needs replacement. The bushing was not offered by Ford NOS so a replacement is needed. Charlie Schwindler can do this or contact Mac VanPelt.

[Mac VP]

There’s an honest effort to provide some help here in this thread so I don’t want to criticize. Perhaps a bit of clarification will be helpful on a couple points.

1) The early mainshafts (32-38) did use a small pin, along with a tiny spring, to help secure a sliding lock key under the early 2nd gear. His particular gear set is a 39-45 type. On those mainshafts Ford placed a 1/8” diameter pin in a matching hole, just ahead of the splines for the low/reverse gear. I’ve personally encountered hardened and non-hardened pins here. The non hardened pins are fairly easily drilled out. The hardened ones can only be drilled out with a special tungsten bit. Use a drill press and a press vice with a rag or thin pieces of wood to clamp the shaft in the jaws of the vice. Use cutting oil and gentle pressure and plenty of patience to drill out the pin. It helps to create a center divot in the pin. We have the factory replacement pins but you can make them yourself easily.

2) The shape of the 7102 second gear did not change in 1951 so the “diamond tip” reference really doesn’t apply here. What changed was the overall diameter. The 81A-7102 gear (used from 1939-50) was roughly 3.03” in diameter. The 1A-7102 gear (used from 1951-55 and newer) was roughly 3.13” diameter. Although they look and measure nearly identical, they are not interchangeable.

[Talkwrench]

Thanks Mac I was hoping you'd see the post.

2. So we're talking .010 difference.. geezzzz.. Umm well guess thats why I couldn't tell just a different "shape of the teeth"
Now saying that they're not interchangeable is the problem as the gear is in and Ive been driving it with no problems - noises etc.. I just dont know if I'm panicking over nothing or could it tear the box apart without me knowing...?

[Talkwrench]

Thanks Mac I was hoping you'd see the post.

2. So we're talking .010 difference.. geezzzz.. Umm well guess thats why I couldn't tell just a different "shape of the teeth"
Now saying that they're not interchangeable is the problem as the gear is in and Ive been driving it with no problems - noises etc.. I just dont know if I'm panicking over nothing or could it tear the box apart without me knowing...?

[Zeke3]

Mac said the difference in diameter was 0.10”, which would be huge in a transmission gear set. You must have something else.

[Talkwrench]

Originally Posted by Zeke3

Mac said the difference in diameter was 0.10”, which would be huge in a transmission gear set. You must have something else.

Take a look at the picture, Its the two different types. 81A and 1A . Pretty sure there's no other...