Transmission / Overdrive: Speedometer Gear for '55 E7

[radioadman1]

My '55 E7 pickup has the Borg Warner R10 overdrive transmission. Although I'm not 100% sure, I'm fairly confident that the rear end gear ratio is 4.55 (factory application with this transmission/OD setup). Would anyone know what the proper speedometer gear would be, and if so, the actual Studebaker part number? When I purchased the truck it was missing. I've ordered the CD rom with the shop/body/chassis numbers, but won't have it for a few days. Many thanks in advance.

[StudeRich]

You WILL have to know for SURE what your Ratio is, many were 4.27 and more, you can't guess.
Can't you just READ the Tag on the Diff. Cover?

[StudeRich]

The 2R to 2 E Truck Parts Catalog does say for Tires and Wheels from 7.10 X 15 UP TO 7.50X16 in a year Code "E", Model 7 (V8) 1/2 Ton with 3 Speed O.D. and a 4.55 or 4.56 Rear, use a: 677744 Pinion (Driven) Gear.

If a 4.27 Rear, use a: 520087

If your truck was built as a Standard 3 Speed, and later was changed to an O.D. Trans. that Changes everything.

[StudeRich]

SORRY, I can't add this to Post #2 !!!!

[radioadman1]

The 2R to 2 E Truck Parts Catalog does say for Tires and Wheels from 7.10 X 15 UP TO 7.50X16 in a year Code "E", Model 7 (V8) 1/2 Ton with 3 Speed O.D. and a 4.55 or 4.56 Rear, use a: 677744 Pinion (Driven) Gear.

If a 4.27 Rear, use a: 520087

If your truck was built as a Standard 3 Speed, and later was changed to an O.D. Trans. that Changes everything.

Thanks Rich, I appreciate it greatly!

[radioadman1]

The 2R to 2 E Truck Parts Catalog does say for Tires and Wheels from 7.10 X 15 UP TO 7.50X16 in a year Code "E", Model 7 (V8) 1/2 Ton with 3 Speed O.D. and a 4.55 or 4.56 Rear, use a: 677744 Pinion (Driven) Gear.

If a 4.27 Rear, use a: 520087

If your truck was built as a Standard 3 Speed, and later was changed to an O.D. Trans. that Changes everything.

Hi Rich, the tag has says 45 with a line under it, and under the line is the number 11. Would this mean the 4.55 ratio upgraded to 4.11? Please see the picture.

[radioadman1]

I calculated the numbers. I believe that this is a 4.09 gear ratio. If you don't mind, please confirm if you would. Thanks!

[StudeRich]

Yes 45 divided by 11 = 4.09, a 45 toothed Ring Gear with a 11 Toothed Pinion Gear, a Very Standard Dana Spicer for Studebaker Ratio.
It means the Truck HAS a 4.09 Ratio Dana, either ordered that way, or changed.

Trucks were built for their use and the rear Axle for that and their ORIGINAL Transmission.

However 4.09 Was Standard in most years on Trucks with a DIRECT 3 Speed without Overdrive depending on which Engine was installed.

[StudeRich]

I guess we need to remember that a "E" Year Truck: ('55) would have the Low Torque, Short Stroke 224 V8 !

[StudeRich]

OK, I checked the Catalog again, the same 520087 Pinion was used for 4.09 as for 4.27 Ratio.

[radioadman1]

Awesome, Rich, many sincere thanks!