Full Size Jeep Network

Alrighty, I got my 727 rebuilt and while it's out I am also doing a NP229 to NP208 swap. Since its on the ground right now I figure it would be an opportune time to swap the speedo gear in the case to match my gearing and tires. Currently I am assuming the gear is for a 29 inch tire and 2.72 gearing. I have 4.10 gearing and 36 inch tires. Anyone have a chart or something telling which speedo gear I should swap to to make my Speedometer a little more accurate once it is moving again?

You can probably use Derfs calculator to get the percentage change.

http://www.grimmjeeper.com/gears.html


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I would physically measure your 36's.
IIRC you have the military take-off, none of the ones I had ever came close to 36" most were around 34.5"
I always just calculated the percent and then did the math in my head for the most part.
When I went to 37's w/4.10's (these actually measure 37") I was so close I just ignore it now.
Stock for me would have been around 2,634 rpms @ 65 mph, now its 2,557 rpms, 77 rpm difference, so about 3% now or 2mph off.

I found a website that has a guide for chevy speedo gears, but I can't remember what it was or where it was....... Sorry and good luck.

http://www.transmissioncenter.net/speed ... ____va.htm

Basic info, has a chart that might help several pages down.

They have a Jeep Only section right below the title once you find out what gear ratio you are looking for.