My guess is that I need to replace this part, but thought I would ask anyway.

'74 New Process (NP-435) Manual Transmission.

About to rebuild the transmission, as I removed the top cover to examine the gears, found that the end of one gear tooth on the Input Shaft Gear is broken off. Should this part be replaced?

I don't see the chip as being a problem other than a possible clickety-click noise in all gears. I'd be more worried about the missing piece getting jammed between gear teeth.

I've seen what seemed like perfectly working transmissions have a flaw similar to that.

You could also ask yourself if you are just going to drive it until it breaks, which may be never or if someone was rebuilding this for me, would I expect to not see this stuff inside my rebuild.

Thanks John and Magnum. Appreciate the replies.

It does disturb me that it's the input shaft and will therefore affect everything else, all the time. If it were just a chip on say, third gear only, the thought of it wouldn't bother me nearly so much.

This trans is out of my '74 Dodge W200 pickup that I bought last November. Haven't driven it much (around 20-miles), as I have been restoring it, piece-by-piece.

All cleaned up on the outside, I'm now ready to disassemble and rebuild the trans. Figure I will find the broken-off piece in the bottom of the case (unless someone else rebuilt it before reusing the damaged gear). Will be inspecting for more damage, but so far, I haven't seen any other chipped gears.

The reason I am rebuilding it, was due to bearing/gear Noises. I think the previous owner may have run the trans low on lubricant (due to significant seal leaks) and burned out the bearings.

I was considering a replacement input shaft, if I can locate one. They look to be around $100. Just didn't want to go to the expense and trouble of locating the part, if that damage was considered as not all that harmful.

Sometimes (on other transmissions or differentials) a chipped tooth seems to not have caused any observable problems.

In contrast, I also read articles that suggest stress, caused by a broken/missing tooth, has caused driven gears to fail as well. Also, that it is good practice to replace gears in pairs, as in both the driver and driven gear.

I rebuilt the trans in my Jeep in 2005, replacing a broken 2nd and related broken cluster gear as well.

Since you are going to tear it down I would dress that down and run it ...

When you come apart with that, pay very close attention to how the second gear synchronizer is assembled. IIRC there is more than one version of that assembly and the FSM is cloudy on reassembly.

Its a helical gear and the next tooth engages before this one disengages. You likely won't hear any noise at all from it. Dress it and run it.

Thank You for all the great New replies.

When I get it apart, maybe I will just dress it out and re-use the input shaft. Worst case, I would need to pull the trans again and replace with a New input if it makes noise.

I have the Dodge Factory manual and there are fairly good instructions included with the Novak rebuild kit I bought (was $294). Looks to be good, quality parts, complete with syncros and instructions.

I would very carefully inspect the tooth and mating gear on the cluster for any signs of fracturing especially if you find the missing chunk in the case. If all looks good run it, if you want to be 100% sure replace it and possibly the cluster as well. Further inspection will guide you which way to go

I'd look for cracks at the root of the tooth. Dye penetrant testing would probably work.

NP435s are everywhere, although Dodge versions are not as plentiful as Ford. You shouldn't have any trouble finding an entire replacement transmission for not too much money.

R.

Good to know. Thanks for the replies.