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Tires And Transmissions?


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I've just spit on the thing before, and then rub it with my thumb until I could read the numbers. WD40 is just a more ... civilized method? 

lol, i thought of that, or just water but either way, under my truck is a mud pit :D

 

Redwolf

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102 posts and still do not know the answer to the ratio question.........

 

I live in Winnipeg Manitoba Canada (goggle it).....I could have driven down to Virginia Beach......rebuilt your diff new to spec....(told you the ratio)

 

....and driven home in less time    . :MJ 1: .

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102 posts and still do not know the answer to the ratio question.........

 

I live in Winnipeg Manitoba Canada (goggle it).....I could have driven down to Virginia Beach......rebuilt your diff new to spec....(told you the ratio)

 

....and driven home in less time    . :MJ 1: .

yeah yeah i know, i keep puttin off crawlin under my MJ

 

Redwolf

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ok, i crawled under my truck, got the numbers on that tag and i can tell that the diff cover has been taken off before i got my truck cause i see where it bolts on with the diff bolts, but anyhow, the tag reads:

54 60529-2

8953003697

 

Redwolf

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AXLE ASSEMBLY, Without Locking Differential . 3.54 Ratio, Tagged 8953003697

Used in 84-86 Jeep XJ, MJ

wow, wish i had known that's all yall needed from the get go for the ear ratio, how'd ya decode it?

 

Redwolf

Parts manual.

where do ya get a parts manual from, i've been lookin for one ever since i've heard of em,

 

Redwolf

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Most people looking for more power start at the engine. Usually optimizing gear ratio and tire size ( which alters final gear ratio) for the engine you have is a way better place to start. The factory gear ratios were a compromise between getting enough performance to get someone to buy the vehicle and achieving higher MPG figures for advertising & regulation purposes. The balance can be achieved. Look at the Yoder 4-bangers which were lucky to put 80 horsepower to the ground yet they do fine due to careful attention to gearing. A shorter tire effectively raises the gear ratio numerically ( even though they are called "lower gears") while a taller tire obviously moves the gear ratio into a lower numerical number for "higher" gearing.

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I have found that the factory average ratios (stock tires with 3.07 and 5 speed or auto and 3.55) seem to be about perfect. The Renix motors (which most MJs are) have the same cam as early HO, but it's timed different. HO timing gear moves the cam retarded about 5-10 degrees, which makes the power at higher RPM (also increasing the HP and torque peak, but to a higher RPM point than Renix)

   It was done that way to decrease NOx and ping (getting rid of the Knock sensor in the process) Jeep modded the trans as well. The O/D ratio changed as well. 5th gear and auto O/D became .75 instead of .70 to make up for the lack of lower RPM grunt.

   My rig (in my profile pic) has 3.73 gears, which were perfect with the BA 10/5 the truck came with and 33" tires. (20 mpg) Originally I tried the 3.07 axle and it SUCKED freeway driving. 5th was flatland or downhill only. Now that I've converted to auto, it really should have 4.10s with the 33", but only with bigger loads.

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