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-   -   Not your average gear ratio question... (http://www.wranglerforum.com/f210/not-your-average-gear-ratio-question-55334.html)

pakman55 07-14-2010 05:15 PM

Not your average gear ratio question...
 
Alright folks I know that the gear ratio questions are dead horses. I have been reading about this. I spent an hour and a half on google reading every link on the first page reguarding my question. So here it is. On a 4 cyl, automatic '01 with 33" tires, should I go with 4.56 or 4.88 for a gear ratio. I was hoping to go with the option that gives better MPG's but still alright performace wise.(I'm already saving every penny to get the gears done) Which one do you recommend? (I'm looking at you Jerry) :D

wasurfer86 07-14-2010 05:26 PM

4.88's

pakman55 07-14-2010 05:27 PM

cool just wanted somebody to hold my hand through the decision. :rofl:

30-284 07-14-2010 06:32 PM

You already have 4.10 ratio so 4.56 wouldn't be a whole lot better, I think I would go at least 4.88 if not more.

Donn

pakman55 07-14-2010 07:11 PM

Quote:

Originally Posted by 30-284 (Post 688246)
You already have 4.10 ratio so 4.56 wouldn't be a whole lot better, I think I would go at least 4.88 if not more.

Donn

i am fairly certain i have 3.73's...its an automatic.

Jerry Bransford 07-14-2010 07:23 PM

With your 3-speed 30RH automatic and 2.5L four-banger, you want to run 4.56 gearing for 33" tires. 4.88 is appropriate for the 2.5L and 33" tires only when the transmission is the 5-speed manual. :)

pakman55 07-14-2010 07:30 PM

Strait from the experts mouth....4.56's it is.

yjkid95 07-14-2010 07:40 PM

not to hijack a thread i just have a question for you jerry would i have the same 3 speed auto tranny in my 2.5 yj? its a 1995 i need to figure out which input gear i have on my t-case for the adapting plate i need

Jerry Bransford 07-14-2010 07:56 PM

Quote:

Originally Posted by yjkid95 (Post 688351)
not to hijack a thread i just have a question for you jerry would i have the same 3 speed auto tranny in my 2.5 yj? its a 1995 i need to figure out which input gear i have on my t-case for the adapting plate i need

Yes, your '95 YJ has the same 30RH transmission. If the t-case in question was set up for the 5-speed which means it has a short input shaft, you'll very likely need an extended output shaft seal for the 30RH. At least that is how it works with the 32RH 3-speed automatic that is used with the 4.0L engine. When I bolted up my old 231 t-case made for the original 5-speed to the new 32RH automatic I converted to, the 32RH gushed ATF out of its output shaft area. I had to install the extended output shaft seal into the 32RH which fixed it. :)

yjkid95 07-14-2010 08:22 PM

Well im putting mine on the back of a 700r4 now i just need to figure out how many splines the input gear has im praying its 23 splines then novak will warranty the output shaft that comes with the adapting kit.

Jerry Bransford 07-14-2010 09:11 PM

You're installing a 700r4 onto your 2.5L engine? I have read a number of times, which I guess qualifies as rumors, that the GM 700r4 takes so much power to turn that you may be sorely disappointed with your power afterwards. The 700r4 was designed for V8 engines so good luck with your 4-banger. I hope the rumors are false but I do know it was designed to be pushed by some pretty healthy V8 engines.

Here's a little info on the 700r4 with a handy schematic wiring diagram for its lockup torque converter. http://www.smokemup.com/tech/700r4.php

wasurfer86 07-15-2010 12:35 AM

Quote:

Originally Posted by Jerry Bransford (Post 688321)
With your 3-speed 30RH automatic and 2.5L four-banger, you want to run 4.56 gearing for 33" tires. 4.88 is appropriate for the 2.5L and 33" tires only when the transmission is the 5-speed manual. :)

i forgot that 4.88s are for the manual. good catch:)


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