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Transmission Question

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donnercm

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All,

I have 1 tooth broken off of my third gear on my BN4 4 speed sideshift.

Can i still run with 1 tooth broken or is this an immediate replacement issue? I drove the car before it ran smooth and didn't notice any problems, just curious.

Does anyone know where to get a third gear?

Thanks,

Chad
 
That is a hard one to predict. The problem is that the next tooth in line is being hammered each time the gear revolves.
I would source a replacement from Healey Surgeons or British Car specialities ASAP.--Fwiw--Keoke
 
I can't help with finding a new gear, but just one comment: gear sets are usually designed to minimize wear. One technique is to prevent the same two teeth from mating on each revolution. If done properly, two given teeth will not mate again until one of the teeth has mated with all the others first. It's called a "hunting tooth" gearset: https://www.azimainc.com/vibman/huntingtoothgearsets.htm

I don't know if that's true of the BN4 gears, but I would bet it is. So, that would extend the remaining life of the other gear teeth, but if you know the tooth is broken you should change the gear ASAP to avoid damage to the mating gear.
 
The issue is the secondary damage that MAY occur ; meaning it could be fine for 100,000 miles ,or you could destroy everything inside the gearbox during the next trip to the store. That kind of thinking could make your decision easier ! We run a 30 yr old Chev 3/4 ton service van in the summer maybe putting 1,000 mi. on it a yr. ,its had a broken tooth on the ring gear in the rear axle for at least 15 yrs now ( found during routine maint.) It doesn't sound any different now than it ever did and who knows how long it has been broken off. Your choice but I wonder how it got broke.
 
BJ8Healeys said:
One technique is to prevent the same two teeth from mating on each revolution. If done properly, two given teeth will not mate again until one of the teeth has mated with all the others first.
Click to expand...

Reminds me of Sunday nights with Marlin Perkins on "Wild Kingdom" discussing the mating habits of the wildebeest. :jester:
 
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