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what gearing would be best for highway driveing?


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ive been tossing ideas around in my head and ive decided I'm going to put my 2.5 in my resto mj . the rear exeel it has init now has 3.07 gears i think so with a 2.5 that would pretty much suck. the other axels ive got are from a 4cyl 4 speed, and a 4cyl 5 speed. ive also got an xj axel that was 4cyl auto. I'm just wondering what one i shoud put in for the 2.5?

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What size tires will you be using?

 

For general street use with stock size tires, I think the 2.5L works well with the 4.10 geas that the factory used behind the 5-speeds. The early 4-cylinder 4-speeds came with 3.55 gears. That's not bad with no overdrive, but 5th gear would be pretty useless with that ratio behind a 2.5L.

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What size tires will you be using?

 

For general street use with stock size tires, I think the 2.5L works well with the 4.10 geas that the factory used behind the 5-speeds. The early 4-cylinder 4-speeds came with 3.55 gears. That's not bad with no overdrive, but 5th gear would be pretty useless with that ratio behind a 2.5L.

the tires thats are on it right now are p 205 /75/15s. they will probably get replaced with 225s once they wear out but thats what it running now.

so ill swap the axel with 4.10s into it.

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Just highway driving? No haulin taters outta the field?

 

 

Off topic, but Jim, drop one set of image brackets: "[ img ] [ /img ]" off of your sig picture, and it will show up.

 

what you have now:

[/img]

 

 

with one set of "img" brackets dropped:

 

 

 

:agree: with the 4.10 recomendation, but either way, the 2.5L is going to be less than great on the highway (atleast around here, with steep hills all over the place).

 

If I wanted a 2.5L highway cruiser MJ, I'd do what I could to tweak a little more out of the 4, keep the truck as light as I possibly could, @ the stock height with a light weight wheel combo (205/75's on aluminum wheels would be ideal).

 

For max economy tho,

my guess would be a similarly equipt 3.07 geared 5spd 4.0L would pull down better MPG on the highway than a 4.10 geared 5spd 2.5L :dunno: (even though the ratings say differently)

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:agree: with the 4.10 recomendation, but either way, the 2.5L is going to be less than great on the highway (atleast around here, with steep hills all over the place).

 

If I wanted a 2.5L highway cruiser MJ, I'd do what I could to tweak a little more out of the 4, keep the truck as light as I possibly could, @ the stock height with a light weight wheel combo (205/75's on aluminum wheels would be ideal).

 

For max economy tho,

my guess would be a similarly equipt 3.07 geared 5spd 4.0L would pull down better MPG on the highway than a 4.10 geared 5spd 2.5L :dunno: (even though the ratings say differently)

 

From the factory, I think the Comanche's highest economy ratings were with the "fuel miser" package, which was - if I remember right - the 2.5, 4sp, 3.31 gears, and then dropping extra weight like the tailgate, spare tire, etc. That sounds like it'd be a dog to drive though, IMO.

 

I currently have the 2.5, 4sp, and 3.55. I generally get mid-low 20's mpg. Mixed highway driving and I have a light foot. It's okay - generally peppy enough around town, and I like the grunt in 2nd & 3rd gears for passing/merging. Where it really struggles it at highway speeds and on hills in 4th. Not enough power to maintain speeds of 55-65mph at grade, and running to many rpms to drop it down into 3rd.

 

I really want to switch mine over to the 5spd and 4.10's. Based on all the advice I've gotten here, definitely sounds like the way to go. I'm willing to sacrifice a few mpg's so I won't have to be stuck in the far right lane with the big rigs, creeping up hills. Now I'm just waiting for one of my driveline parts to fail, so I'll have a legitimate excuse to spend the $$ :D

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What size tires will you be using?

 

For general street use with stock size tires, I think the 2.5L works well with the 4.10 geas that the factory used behind the 5-speeds. The early 4-cylinder 4-speeds came with 3.55 gears. That's not bad with no overdrive, but 5th gear would be pretty useless with that ratio behind a 2.5L.

 

AX-5 with 3.55 on 205/75/R15s isn't that bad..

 

With MPFI..

 

And level highway at 70mph.

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