Speedometer re-calibration for bigger tires

[The War Wagon]

Do you just tape ye old 10mph increment differential chart/post-it note to your dash?

OR...

Do you do the OFFICIAL re-calibration?


And IF so, HOW so?  Anyone ever try one of these?

http://www.jegs.com/i/Superlift+Suspension+Systems/426/33002/10002/-1

Anyone use something ELSE?

[workgoats]

I didn't think that would work on anything older than 1989.  Up to that time (more or less) the Dodge trucks used a mechanical speedo.

I have always changed out the drive gear for the speedometer.  There are a lot of different tooth numbers and I have always been able to find one in my pile of speedo and transmission misc. stuff the will work.  Virtually all of the old Chrysler transmissions and NP transfer cases use interchangable gears.

[crazzywolfie]

it is not worth $150 for it. you could buy a new speedo gear for less

[The War Wagon]

it is not worth $150 for it. you could buy a new speedo gear for less

Cool.  Now where do I get one of THOSE?   

[crazzywolfie]

could try calling transmission shops but you will need to know what gears/tires you have to figure out what gear you will need.
this place has them for $39
http://www.transmissioncenter.org/speedometer_gears_for_dodge_and_jeep.htm

[The War Wagon]

could try calling transmission shops but you will need to know what gears/tires you have to figure out what gear you will need.
this place has them for $39
http://www.transmissioncenter.org/speedometer_gears_for_dodge_and_jeep.htm

Thanks for the link - that's definitely bookmarked.

My man at Gibbs actually chimed into this question (I cross-posted it at Pittsburgh offroad.com), and mentioned that since I've re-geared it, it might be pretty close to accurate now.  That, and the po' boy's way to check it, would be with a GPS unit!  I don't have one, but suppose I could bum one first, and check it out!

[workgoats]

Here are a couple of charts that were put together some years back by DodgeBoys.

As for the GPS, if you have a smart phone there are some apps for $1 or less that can do the job.

[ProjectM880]

Here are a couple of charts that were put together some years back by DodgeBoys.

As for the GPS, if you have a smart phone there are some apps for $1 or less that can do the job.

Ron are these for teh gear in the T-case or in the actual speedo?

[workgoats]

The 2x 727 or 903 and the NP transfer cases use the same gears.  They are either in the transmission tail housing or the transfer case.  I think the long gears go from the beginning until 1989 or 1990.  Some time after that the probably go to a shorter gear.

The 1988 has TBI but uses the mechanical speedo.  Either in 89 or 90 they did away with the mechanical speedo.

Pretty much all mechanical speedos are calibrated the same.  I used a 50's Willys speedo with a drum out of a thunderbird and fed it from a Ford transfer case, later from a Dodge transfer case and it always read the same.

[workgoats]

Before you guys spend a lot of money buying a gear, determine how many teeth you need.  I have several and other guys probably have some too.  I bet that with the junk sitting behind Brutal Off Road that James has a bunch...

I've seen prices from $24 for used to $120+ for new.  They aren't worth that much...(unless you don't have one)

[SixGun]

Yellow 30 teeth short tail if you got one.

  33's 3.55 & electronic speedo on the 91.

[workgoats]

Yellow 30 teeth short tail if you got one.

  33's 3.55 & electronic speedo on the 91.

Every single one that I have is older (long gears)

[SixGun]

Shucks