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Discussion Starter #1
I called both local Jeep dealers looking for a new speedo gear for my '95 ZJ. From the tech article on JeepsUnlimited.com, it looks like I need a 32 tooth gear (3:55 axle ratio and 31" tires). However, both Jeep dealers told me that Jeep does not make a 32 tooth gear. What gives? Anybody else run into this problem?
 

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Discussion Starter #2
After poking around a little more (a couple of more websites), I found the following part number - 52067632, but the dealer told me this part number does not fit/correspond with a ZJ. Anybody out there change their speedo gear after putting 31's on their 4.0L ZJ? Is this the right part number? Does it fit the ZJ?
 

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Check here:
http://www.jeepsunlimited.com/zj/techtip/speedocal.htm

You're going to need to figure out your gear ratio in the back. With the 4.0, you probably have 3.55. 3.73 was an option on them though. With 31's you're going to need either a SG32 or SG33. You should be able to just go to the dealer and tell them the tooth count you need. Heck! They have that nice computer in there for a reason! :D

Hank
 

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Discussion Starter #4
That's the website where I started; in fact, that site had/has an update from November of 1999 that now lists the Mopar part numbers for the specific speedo gears.(In fact, that's where I got the idea to change the speedo gear and that I need a 32 tooth gear.) I also have already determined through the dealer, using my VIN, that I have a 3:55 axle ratio. I guess what I am really wondering is why the dealer told me that part 52067632 (the 32 tooth speedo gear) is not for use in the ZJ. From what I can tell on http://www.jeepsunlimited.com and http://www.imajeep.com, this is the right part number for a 32 tooth speedo gear for a ZJ. Wondering if anyone else bought this particular part and whether or not it works.
 

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That looks like the right PN. I've done it, and it works. Its actually a pretty easy install, just make sure you note the position of the sensor when you take it out and put it in the same way. The speedo gear just snaps into place. The dealer will probably have to order it for you, but I don't see why they say that's the wrong number.
Hank
 

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Discussion Starter #7
Update - 2 days ago, when I pulled the stock SG from my ZJ, I found out that it was a 36 gear, not a 34 like all the charts all over the web say it should have been. When I put the 32 tooth gear in, I went from reading 5 MPH under to 5 MPH over. I called the dealer and he told me that nearly all 4.0L ZJ's with 3:55 gears were equipped with 36 tooth stock SG's, not 34's, and that the 34 tooth SG is the one to use when going to 31 inch tires with the 3:55 gears. (Which would make perfect sense, as the 36 tooth was low and the 34 tooth was high.) So, the long and the short of it is don't trust everything posted on these sites!
 

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I to am having the same problem. The part number that I got of the net is rong. I am showing about 10 MPH over actual speed. Does any one know the right part number for a 94 4.0 3.73?
 

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Why are you going everywhere else to find your information when it is right here on our very own Grand Tech page
:bang:

Forget about what the dealer says about that gear # not showing up in their computer for a Grand. Grands don't come with 31"+ tires so that gear won't show up in thier books. Just get the gear and install it. Follow the provided instructions in the write up, here on the site. Good luck
 

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Discussion Starter #10
If you read my prior posts, that's exactly what I did. The gearing/tire size chart on the NACGA tech page is the EXACT same one I found on other web pages and, from my experience, IT IS WRONG. The directions that are with the chart are fine - I had no problem changing out the gear. The part numbers are also correct. The problem is that the gear/tire size chart itself appears to be incorrect. With 3:55 gears and 28" stock tires, my ZJ came with a stock 36 tooth speedo gear, not a 34 like these charts state. Furthermore, when I put in the 32 tooth gear, per the chart, I went from reading 5 MPH under to 5 MPH over. So, I just want to warn others that before they change their speedo gear NOT to rely on this mass-copied incorrect chart!
 

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What speedo gear do i need with a 97 grand with a v-8,3.73 gears and 31`s? Someone told me the chart on this site is incorrect.
 

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Discussion Starter #12
Update - Put the 34 tooth speedo gear in this weekend - now my speedo is right on the money!
 
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