Changing the Speedometer

[Dhardt]

Looks like its aprox 3.25

 

[JOLENE_THE_RANGER]

could be 3.27 or 3.45. not sure what rear end you have but im not sure the 3.27 was offered in the 7.5 axle so if you do have a 7.5 axle one you can assume its 3.45

 

[RonD]

29" tires are within speedometer gears available, 235/75r15 = 29" diameter

BW1350 transfer case should have 7 tooth worm gear/drive gear

Look here to get axle ratio: https://therangerstation.com/tech_library/axle_codes.shtml

Easiest is if its on the drivers door label


EDIT:
If it is 3.27 ratio then yes you would need 16 tooth driven gear
If you could find an 8 tooth worm gear for the BW1350 then you could use an 18 tooth driven gear

If ratio is 3.45 then 17 tooth is closest to correct

 

[Dhardt]

In that case it would have to be 3.27 because I have a 17 tooth and when the speedometer says 62 my phone says 70.

 

[JOLENE_THE_RANGER]

16 tooth should get you real close. or you can change the gear on the output shaft as ron d said

 

[adsm08]

In that case it would have to be 3.27 because I have a 17 tooth and when the speedometer says 62 my phone says 70.

That' doesn't make a lot of sense. 3.27 was only offered in a 4.0.

 

[Dhardt]

Honestly they guy I got the truck from did a lot of work on it. I'm not sure what all he changed on it.

 

[Shran]

What rear axle is in the truck? Is it a 7.5 (would have been from the factory) or has something else been swapped in? 8.8 perhaps?

 

[RonD]

This site makes the ratio adapters that would just screw on to the transfer case and then you screw on the speedo cable to the adpater

https://transmissioncenter.net/shop/54ra2-gm-dodge-ford-ratio-adapter/

And they have a selection for an 11% increase

 

[Dhardt]

Cool I'll have to look into that thank you.