Speedo Adjustment

[motormayhem]

My m1009 has been off by about 20MPH for the last 4 years which I don't really mind other than the odometer artificially skyrocketing. I'm running 4.10 gears and 36in tires. I've heard there is a converter box on the M1009 that changes the speedo ratio as well as the gears in the T case. Do I need to swap the converter/gears in there or the drive/driven in the Tcase? My truck is currently 15 hrs away so I would appreciate it if someone could give me some insight on what I need to plan to change / order swap it out when am home for a few days over the holiday.

 

[doghead]

You need to look under it and see if there is a "converter box".

Once that is known, you need to use a calculator and determine what gear you need.

TCI has both the gears and the calculator.

 

[motormayhem]

Thanks, do you happen to know what the stock drive and driven gear colors are? I can't look at the truck as it is 15 hours away and I want to be able to just throw the parts in when I'm back for a few days over the holiday.

 

[motormayhem]

Pulled the converter box out and it's about 3-5 mph slow which is close enought. That's with 4.10's and 36's