View Full Version : Speedo/Tach/Gauges How to identify speedometer driven pinion gears? Who's got 'em?

07-24-2012, 02:42 PM
I've never paid much attention to the speedometer cables, as it usually stayed with the car. Now, I'm finding five different variations in a sample of three.

There are three speedo cables and two have 1" diameter bullets on the tranny end and the third maybe from a '64 T10, has an .875" bullet with an O-ring.

One, maybe from a C-cab truck, has a larger diameter cable housing than the two believed to be from cars.

I've got two Studebaker speedometer cable pinions. Both have 16 teeth. Both are the same length. One is larger in the gear diameter than the other. Looking at the side of the gear, the larger diameter (.8375") gear teeth slant up and to the right. The smaller diameter (.7790") gear teeth slant up and to the left.

The the two could have come from any one of four V8 trannies - T85, T86, T10 or T98.

1. Which is most likely the gear for the T85/T89?

2. As near as I can tell from part numbers, the T85/T89, T10 and T86 speedo pinons are interchangeable. Can anyone confirm this?

3. This will be going in a truck with a T89 3-speed overdrive, 4.11 rear axle ratio and 215/85-16 tires which turn 681 rev per mile. This is about the same as the old 7.00x16" and 21.2 MPH/1000 RPMs in 1:1 high gear.

As near as I can tell from my old parts book this would need a 682015 speedometer driven pinion. Would this be a 17-tooth pinion? If so, does anyone have one for sale?

Any speedometer experts care to calculate what speedo pinion this combination would need?

jack vines

07-24-2012, 03:05 PM
If I remember right, some tailshaft housings have the speedo pinion placed above the worm, and others below, hence the LH vs RH pinions. I know I put the wrong one in a '54 Champion once, and it didn't last very long!

If you grab a speedo worm from your parts stash, it should be easy to figure out the handedness thing. I also seem to remember that the OD governor worm is a larger diameter than the speedo worm.

07-24-2012, 04:10 PM
I would suspect that one is for an automatic and the other is for a manual transmission.

07-24-2012, 04:48 PM
Anything is possible, but I was 99% sure both gears came from manual transmissions. However with all the parts and transmissions, one could have snuck in somehow.

jack vines

07-24-2012, 07:01 PM
Jack, read the Studebaker stock no. imprinted on the side of the pinion shaft, then look them up in section 1716. Dan

07-25-2012, 11:36 AM
Dan, you are, of course, correct. Since the shafts are the same, I assumed incorrectly any number would be on the gear. After wiping off the old grease and getting them in bright sunlight, there are very faint, very tiny numbers stamped around the shaft.

Would appreciate it if Dan and the other Parts Manual experts would check me out on the Parts Manual interpretation on this.

Smaller gear - SW 448130 520088 - for 16G6 cars with 6.40 tires and 4.1 axle or 56G with 6.70 tires and 4.27 axle. Both would be Champion 6-cyl with T96, correct? This appears to indicate the T96 uses a different 16-tooth gear than the T86/T85/T10 as there are two different p/n.
If this is so, I can't imagine where I got this gear, as I haven't had a Champion on the place in the past forty-five years.

Larger gear - SW 448885 1556040 - can't find this one in either my truck or my car parts manual. Any one with sharper eyes?

jack vines

07-25-2012, 02:26 PM
Jack, I no longer have my '47-50 parts manual, so can't do you any good on the 520088. But the Stude part no. 1556040 (Stewart Warner No. 448885), is from a late model four speed with a 3.07 rear end! I've got that odd combo in my 64 R1 Super Hawk. Dan

07-25-2012, 03:47 PM
Thanks, Dan. It must have come from a totally rusted '64 GT I parted out. Out of a junk yard in Gulf Shores, AL, it was a 225hp 4-speed, red with the white vinyl half roof. I've still got the shifter, trans tunnel cover, clutch and brake mechanism, side trim and some misc gauges.

jack vines

08-02-2012, 11:33 PM
520088 fits several:
47-50 Champion 4.1 ratio
And 50 Commander 4.55 ratio