Speedometer Drive For 1974 Cj5

I have a 1974 CJ5 which is stock with the 258 engine, 3 speed, and factory transfer case. 31" tires have been added. What speedo drive should I use? How many teeth? And where is good place to source. Thanks!

 

The first step would be to verify how many teeth your driven gear currently has.
You remove the speedometer cable from the threaded adapter at the transfer case.
Unscrew that adapter, then you can remove the driven gear.
Record the SW number stamped into the shaft of the gear; record the number of teeth as well.
Hypothetically, let's say your speedometer is reading too slow and you have a 16 tooth driven gear.
You would look for a 15 tooth gear which would speed the gear up to go faster.
On the other hand, if it's reading too fast, you would look for a 17 tooth gear to slow it down.
Keep in mind 1 tooth equals about 5-6 mph in reading on the gauge.
Caution: you must stay within the SW number series that will be stamped into the driven gear.
You can not deviate from that series, or just install any driven gear or damage will occur.
An example of the number would be: SW 448137
Also, the gears could be hard to find, although some off shore repro stuff is starting to appear.

 

Have you tried your existing speedo drive yet Limeport?

When I rebuilt mine it was spot on accurate with 31" rubber according to the GPS compared to the speedo reading.