Swapped my speedo gear

[hi_c]

Well, I finally got around to swapping out my speedometer gear in the tail housing of my t-case. It was much easier than I thought. I should've done it eons ago. I bought the 35 tooth gear from a guy in my Jeepclub for $5 about 3 months ago. My original gear was a 41 tooth (for 4.10s with 27" tires). So you can imagine how far off my speedo and odometer were. The charts I've read say I need everything from 34 to 36, so I figured 35 is what my buddy has, and 35 is right smack in the middle. So now I realize how slow 45mph is. Before, when the speedo said 45, I was really doing about 52. It was a 16% difference. Which also means that I only racked up 84% of the miles that I actually travelled.... hmmm, this could be a way to fraud vehicular miles. I guess... technically I already have. :twisted: Good thing I'll be the last owner of this Jeep.

Moral: if you haven't done this mod yet.... do it. It's cake.

corey

 

[Bounty__Hunter]

I did this with the same size speedo gears, piece of cake. Mine was a '95. I found my parts XJ had the 35 tooth gear (4.0L auto 3.55 gears) so cost was minimal Otherwise I think they're only about $12 at the stealership.

 

[Bounty__Hunter]

I highly recommend somebody do this swap if they're running a computer controlled auto transmission like the AW4 in XJ's and MJ's, the TCM that is the brains of the transmission uses the speedo gear input in it's normal operation and it's important that the signal be accurate after a tire change.

 

[jeepmaster]

i went up like .6" on my tires. im gonna wait til i go bigger

 

[Bounty__Hunter]

Good idea, I don't think they make a speedo gear for .02% +- change in tire height.

 

[LGR]

yeah, changed mine during my SYE install, was cake, took two minutes. I spent more time looking at the two gears togather after i pulled the old one out then it took to change it

 

[laneiac]

Where do you find out which tooth gear you need? I need one for 32/33s with 3.07s and one for 35's with 4.56s

 

[LGR]

http://www.raingler.com/jeepReference/speedoChart.html

that should help.

 

[LGR]

found another, this one looks like it has alot more options and info.

http://www.go.jeep-xj.info/HowtoSpeedoGears.htm

 

[laneiac]

Thank you good sir.

 

[Tombredone]

What about a speedo gear for a 79CJ5,,, where can I locate the one i need for that?????

 

[hi_c]

tombredone,
you'd have to find one out of another vehicle with the same transfer case as yours and a different axle gear ratio. Use the calculator link above and find out how many teeth you need for your gear. Then go t-case hunting. Good luck.

corey

 

[Enzo16]

how do I figure out for my jeep wrangler 1991 yj with 35" tires?

 

[LGR]

I posted some links above, all the info yo need should be there.