correct speedo gear ?

[jp0863]

i did the search on here and didn't come up with anything that i needed. im running an 89 np241 in my 85. when i swapped from the 3.08 gears to the 4.10 gears the speedometer is waaay off. anyone know which speedometer gear i need to replace mine with? there's also a small "box" looking thing on the cable after it comes out of the t-case, what is this for? what all would i need to do to correct the speedo? im running 4.10 gears with 35's..thanks.

 

[Cowboy_80]

The best option is to go the route I went on my '64. Bring your rig to a speedo shop and they'll build a little gear box for you that will match everything up perfectly. They hook their calibration thingy up to your tranny and your speedo, drive it a few feet, figure out what they need to know, and presto, you're fixed. Took about 15 minutes and $100.

*Edit... I finished reading your post. The box looking thing on you t-case is what I'm talking about. Heck, just remove it and see what you get.

 

[jp0863]

ok, ill try that.