Changing gears on 31's

[Jerry Bransford]

Was it hard to convert it to an auto? Was it expensive? What year did you take the Auto from? Manual is fun an all, but since I drive downtown daily it gets annoying sometimes

It wasn't technically hard but there was a lot of work to it which took the better part of a weekend... and oddly enough everything worked fine after a friend & I were done. But that was on my previous '97 TJ and there'd be a little more to doing that kind of swap to your '06 where the 42RLE transmission used for that is computer controlled where my '97's was not. I paid roughly $1100 for everything once I was done but I did get a smoking deal on a complete 32RH package which is the automatic transmission used on 2002 and older TJs with the 4.0L engine.

There's another better transmission you could convert to called the AW-4 (also a 4-speed but with a much better Overdrive ratio than the 42RLE) which came in older Cherokees but I don't have a clue on if that is easier or harder once you get up to newer TJs like yours.

 

[Kevin E]

Sorry guys I totally forgot to mention I have 4.0L 5 spd manual. That might help lol. I'm at work so my brain is a little scattered!
I got that quote from suburban driveline which is a shop that specializes in this stuff. I am going to call around.

4.0 liter 5 speed 1998 Sport and have 3.07 gears with 33" tires and have no problems cruising at 70 mph in 4th gear at around 2300 rpm's. 5th gear is useless. I saw in previous post you said no power in 4th and even 3rd. Thought that was strange. What kind of rpm's are you getting on the highway in 4th at say 65mph or so? You should be able to cruise around in at least 4 gears with 31 inch tires. Driving around town I am usually no more than 3rd gear. I wonder if gears are the problem? Engine sounds good?

 

[billiebob]

S
I have 31's on my stock TJ and I got quoted $2500 to change the axle gear. My jeep is sluggish in 4th gear especially up hills and highway driving. I can't pass people because the jeep is ridiculously slow. 3rd gear isn't any better either.

I had 3.07s in my '87 for 10+ years with 33s. So 4th gear won't pull.... DOWNSHIFT !!!! nothing wrong with 3rd.. or 2nd.. All that counts is rpm.... you want to accelerate ?????? pick the gear that keeps you over 3000rpm.

There are places you might NEED a deeper ratio than 3.07 but a DD on the highway.... Why spend $2500.00 ???? If 3rd gear is no better than 4th, you have issues a gear change will not help.

Note, I never used 5th in 2HI/4HI but that 3.07 made my YJ a sports car in 4LO on forestry roads or the beach.
4LO, 5th gear, 4000rpm, is 60mph... with 3.07s

Everyone is bending over to the current trend for ultraslow gearing, Rubicon boxes and CRAWLING. 15 years ago only the fringe of four wheelers went there. A bit of speed is way more fun.

 

[Stinger]

IHHO.

 

[Chris]

I think we can all agree that gearing ultimately does come down to personal preference.

 

[mrblaine]

I think we can all agree that gearing ultimately does come down to personal preference.

Not in the least. Take a bone stock auto in the 03 and up and toss 35" tires on it. Your personal preference will quickly tell you something is horribly wrong. Put 4.88's and 33's with the auto in a 97-02 and you will quickly understand that again, something is not right.

 

[billiebob]

In this thread the OP has 31s, a 4.0L and 5speed.