VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Prop Shaft Identification

Developed a grinding sound in my superior rear end and suspected it was the Babbitt thrust bearings having disintegrated. When I tore the rear down yesterday I found that the prop shat was in too deep and it destroyed the ring and pinon gears and ground off about half of the pinion gear nut and about 1/2" off the end of shaft. I am suspecting that someone used a prop shaft for the straight cut gears which allowed the pinion gear and shaft to extend too far into the differential housing. Below are two photos of the different shafts. can someone identify which one is correct for the spiral cut gears?

The first photo is like what I currently have in my car with spiral cut gears however the second photo is supposedly for the spiral cut gears. My combined parts list lists the prop shaft for straight cut shaft as having a 15/16 inch taper but doesn't give the taper length for the spiral cut prop shaft. Any insight or help greatly appreciated. Thanks! Tom

The first photo is the correct shaft for spiral cut gears, if used with the original pinion gear with a shoulder for the ball bearing (part # 24762 in the Combined Parts List Four Ninety and Superior Models, effective on and after February 1st, 1924) and the special woodruff key with a low profile (24049).
The taper length is approximately 51,5 mm.
The second photo has a rear end taper that fits the original pinion gear with straight cut gears (H 94?), but it can also be fitted with an aftermarket pinion gear with spiral cut gears. A couple of vendors offered a conversion set, including ring and pinion gears and the "Differential Ball Thrust Bearing" (part # H 1022). I am quite certain that these conversion sets also fitted Ford Model T. I have seen parts or descriptions of sets with both 9:33 and 9:34 gear ratios.
For both shafts the pinion rear nut must be of the low-profile kind, part # H 669.
I am sorry to hear that your ring and pinion gears are "destroyed". If so, maybe you can have some help from my thread on drive shaft,ring and pinion gears and rear axle.

Swedechev,
Many thanks for your informative response, greatly appreciated! Your post and your website has helped me immensely! Fortunately about 6 years ago while looking for a replacement leaf spring I found a complete ring and pinion set, with new bearings and differential carrier that was sealed in cosmoline. After a good cleaning they look so nice I hate to hide them inside the rear axle. I found a replacement propeller shaft (first picture) and the only thing remaining is to find 2 axles. Both of them are extremely worn on the bearing lands. As a side note, your tip about the Ford thrust bearings was also a blessing. They fit perfectly!
I will post a series of photos shortly showing the damage to the old rear.
Thanks again, Tom