Countershaft Low Gear

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Countershaft Low Gear

Postby JerrryR » Sun Dec 15, 2019 8:03 pm

Hi All Again,
Another question concerning transmission gears 52 to 69. I'm trying to determine how to distinguish the countershaft Low Gear PN 35759-54 from the 35760-54. Both have 17 teeth. The difference in them appears to the Countershaft Speedometer Drive Gear that attaches to the low gear. It is curious that the same speedometer gear was used for the 52 & 53 Ks and then from 57 on. A different speedometer gear was used for the 54 through 56 Ks. Following are images from the PB showing the applications and a picture of one of the gears, which i'm not sure. Any help in identifying them would be greatly appreciated. Pictures showing the difference would be even better.
Thanks,
JerryR

Countershaft Speedometer Drive Gear.jpg
Countershaft Speedometer Drive Gear.jpg (27.65 KiB) Viewed 10459 times


35760-52, 2.1.jpg
35760-52, 2.1.jpg (20.72 KiB) Viewed 10459 times
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Re: Countershaft Low Gear

Postby EKHKHK56 » Mon Dec 16, 2019 2:02 am

I think, can't remember for sure, early Low C Shaft Gear has a larger ID where it rides over the larger early Bearing and Support. Therefore the ID of Speedo Gear is also larger. The new 54 Bearing had a smaller overall dimension, ID and OD so the Case Bearing Support was smaller. This was followed with matching smaller ID on Low Gear? Than I believe by 57 the shaft bearing Support part of case was enlarged for strength, like it was on earlier. Early gear had a little different shaped dogs. 54 and up were a bit stronger. One Gear is recessed in more also looks like...The difference in Bearing OD between 1952/54 is .125" Ok going out to shed to get some samples and verfy!! Got a stack, I will thaw them out and clean them up, check back. I maybe all wrong :shock: ..Erik
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Re: Countershaft Low Gear

Postby EKHKHK56 » Mon Dec 16, 2019 4:49 pm

Ok I woke up this morning, got coffee, found gears thawed out. Called Noot! :P Ok one gear has 17 teeth the other 18. Also Dogs have been re-worked, and possibly metal update like other 54 gears. Speedo drive gears are similar but slightly different pitch/ratio. They interchange but make noise if not matched. Hmm possible binding issue that could lead to failure and case blow out if miss matched? Theories on different IDs were just my one eyed look at dirty frozen gears with a yardstick. Junk science, couch theory debunked. So the 52-53 PB should show the early gear and teeth number. Erik Thanks Noot!
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Re: Countershaft Low Gear

Postby EKHKHK56 » Mon Dec 16, 2019 4:59 pm

17 tooth on left, 18 on right.
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IMG_20191216_120254_resized.jpg
K XL Low Gear C shaft
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Re: Countershaft Low Gear

Postby JerrryR » Mon Dec 16, 2019 6:10 pm

Hi Erik,
I'm still a little confused. I get that the 52-53 CSL Gear has 18 teeth. The challenge for identifying the 54 through 56 CSL Gear from the 57 and on is that they both appear to have 17 teeth. Are there any pronounced features that differentiate one from another?
Thanks again,
JerryR

37538-56, 3.jpg
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Re: Countershaft Low Gear

Postby EKHKHK56 » Tue Dec 17, 2019 2:49 am

Only thing I really see different is style of cut on engaging dogs, and different number of teeth. Its probable that either gear would work per choice, and run against same Main gear. H-D thing, seems strange, but they would change the gear root enough to get good contact. The different speedo gears would compensate for different ratio.
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Re: Countershaft Low Gear

Postby EKHKHK56 » Sat Jan 25, 2020 5:47 pm

Jerry, I see now there are 3 low gears at least ;) 1952 1954 1957 35760-52 35759-54 35760-54 My -56 book didn't show the last one because it's 57 Sportster. This is interesting. All 3 use same bushing. #1& #3 use same # teeth and same speedo gear. #2 is KH KHK only with its own speedo gear and I thought 18 teeth, a little taller for the stroker motor. How do we get 18 teeth for 52-53 & 57, seems backwards. I have an early trans photo looks like 17 style dogs 52-53. Is it listed in early Parts Book or where? I can't recall. Working on this mystery of 52 & 57 difference. So H-D definitely used ratio changes with just one gear change, not both drive and driven ones. C/S and M/S. Erik
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20200123_234532_resized.jpg
Describes gear changes singly, not as set
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