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Discussion Starter · #1 ·
I have a 92 and had no reason to suspect that my gear ratio had been changed from stock. The drive shaft spins just over 2 revolutions for every revolution of the wheel so I spun it around 35 times for an exact number of 17 revolutions of the wheel which calculates out to 2.06:1. Seems a bit low. Did jeep sell a 2.06 diff? I searched on it and didn't find anything.
 

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I am signing up here...... I do not know what is wrong....but it IS something....
 

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if you turned one tire only you divide the revolutions by 2. sounds like you have a 4.10 gear ratio. best way to be sure is pull the cover and read the numbers on the ring gear.
there are a bunch of vids on youtube to show you how.
 

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I would pull the diff cover off and count the teeth on the ring and compare it to the pinion teeth. There's a way you can calculate the ratio by doing that. That seems way too high. Doing the spin test you did is also accurate, but just to make sure take a peak inside to see if it was actually changed out.
 

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Did you change tire sizes?
 

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Discussion Starter · #6 ·
I bought the jeep the way that it is so I don't know what may have been done different than stock. I did spin one side and the other side was stationary. I didn't know that would have an effect on the ratio. Tire diameter is 31inches. I currently have the transfer case in pieces because I am doing a slip joint eliminator. Had to order a complete rebuild kit when I found what I found inside. Oil appeared to be contaminated and it looked like it hadn't been completely rebuilt since it was new. When it was running,, the speedometer was indicating about 5mph too slow at highway speeds. So, I figured I would do a gear change in the speedometer pickup to correct the odometer. The odometer gear change requires gear ratio of the rear end and tire size to figure out what gear for the sender.
 

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Yeah. 31's are going to affect your speedo by quite a bit. They were originally 28's. I'm at about a 38 tooth now on my 2.5 after installing 31's.
 

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Discussion Starter · #8 ·
I was working on it tonight and got the following numbers off of the differential: Dana 43225, 282 1, Rev. E, 3/16/91
The differential has a 10 bolt pattern. Another curious thing is that the fill hole on the cover has no apparent way of opening. It looks like it is sealed with silicone sealant. Shouldn't there be a fill and drain hole on the cover? Or is that on the casting side?
 

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The D35 came stock with a rubber plug in the fill hole, You pry it out with a flat blade screw driver.

None of the YJ rears have a drain plug. The only way to get the fluid out is to remove the cover.
 

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Discussion Starter · #10 ·
OK, after reading some more, because my differential is an open type, then two revolutions of the wheel produces slightly more than 4 revolutions of the drive shaft that would mean 4.1 gear ratio?
 

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Discussion Starter · #11 ·
OK on the rubber plug. That is what it looked like. Now I know how to check the level. Thanks.
 

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Yes, if it is a stock 2.5L motor, then the gear ratio stock would be 4.10.

If you pull the cover to change the gear oil, it will be stamped into the face of the ring gear.
 
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