Changing gears on 31's

Amanda

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So I asked this question on Facebook and got blocked! So please don't dismiss me here. Thank you!
I have 31's on my stock TJ and I got quoted $2500 to change the axle gear. Does anyone think this is reasonable price? Should I even do it? 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.
 
So I asked this question on Facebook and got blocked! So please don't dismiss me here. Thank you!
I have 31's on my stock TJ and I got quoted $2500 to change the axle gear. Does anyone think this is reasonable price? Should I even do it? 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.
Not possible to give you an accurate answer without knowing more. What gears do you have now? As far as the price, that is a regional thing. In this area, I pay around 300 bucks and end for the labor and anywhere from 2-400 for the parts per end not including the carrier.

If you stay below the carrier break, you won't need new differentials so the cost would only include gears, set up kits and labor. Make sure they do front seals at the same time and to either acquire them separately or get the install kit that includes them.

As far as the sluggish goes, what RPM are you keeping the engine at? It is common for folks to under rev these motors because they think it is bad for them. If you want power, you need RPM.
 
You don't mention the year or type axle you have now. However, cost is also relative to the part of the country in which the job is done. West coast for both axles, replacing both ring and pin ions would be about half that- parts and labor.
 
I have an 01 tj I think with Dana 30
Front and Dana 44 rear with 3.07 gear. My jeep is completely stock except for the tires. I just bought it in July and I already want all these mods lol. I was told increasing power would break my axle without upgrading to 3.73 but I don't have 2500 dollars. I live 60 miles north of Chicago just by Wisconsin Illinois border. They quoted me based on labor and parts for both front and rear. I think parts alone was $800. I'm not trying to add a shit ton of horsepower so I don't see how the axles would break.
 
I would find a different shop! Their explanation doesnt make sense to me
Guessing you have a 4 cylinder. Changing gears would give you more ump but probably at a cost of deceased mpg .
If the 6 cyl, well actually the same comment. However going to a larger tire without rehearing will be a big disappointment if you are unhappy now.
Depending on how you drive it simply changing different ratios should not have any impact on axles.
If you are going to do a bunch of off road in and wheel spinning then yes lower gears add a torque multiplyer that probably will raise hell with the stock axles, particularly the Dana 30.
 
3.07 is a horrific ratio, it is the work of the devil. $2500 is way excessive just to change your axle gear ratio unless you also asked them to add other upgrades like Detroit Truetrac limited slip differentials too. $1300-1600 seems pretty typical just to replace the gears from shops that do a lot of regearing.

4x4 stores will be more reasonably priced at doing that job than an axle shop or general purpose garage will since they do so many and they're done for a typically more astute customer. Shop around and push back on the price first quoted, they normally ask for full-price hoping you'll just accept the first price quoted but most will discount it if you push them to.
 
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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.
 
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A shop called "Suburban Driveline" is exactly the type of shop I would expect to quote a high price like that. Look for a 4x4 shop that works on Jeeps and other 4x4 vehicles. :)
 
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A shop called "Suburban Driveline" is exactly the type of shop I would expect to quote a high price like that. Look for a 4x4 shop that works on Jeeps and other 4x4 vehicles. :)

Not to steal the thread or anything but I just had a question… I have a 4.0L, 6 Speed, Dana 44 Rear, with 3.73 gears. I have 31"s Does my Jeep need any thing or is it fine how it is. I don't want to blow up a rear diff, driveline, etc. I don't do much off roading and its my daily driver so I didn't want to cause any damage to it. I had the new tires on it for 6 months now. It seems ok. fuel economy plummeted but oh well lol… Mud tires will do that :p
 
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$2500 is WAYYYYYY too much!

I paid $600 for gears and then $600 for labor ($300 per axle). If you find a good Jeep mechanic (someone who knows their shit), that is about the going rate.

Look around, call around and if you have any local Jeep clubs ask them (because I can almost guarantee that they will know a good go-to guy who is local).
 
It's fine as it is, especially since you have the lower ratio 6-speed transmission. :)

I feel like the RPM should be running at a little lower when I'm on the highway. I usually cruse at around 110kph so about 68mph and it runs at about 2500. It seems a bit high compered to my friends mustang which runs at 1500 at the same speed. I know they are different cars but even my honda would only be at 2000 at 110.
 
I feel like the RPM should be running at a little lower when I'm on the highway. I usually cruse at around 110kph so about 68mph and it runs at about 2500. It seems a bit high compered to my friends mustang which runs at 1500 at the same speed. I know they are different cars but even my honda would only be at 2000 at 110.
Those RPMs are right where they should be for a Jeep running 31" tires. Lighter weight cars or cars with V8 engines don't require as high of an RPM. Your TJ's engine RPMs were higher than that when it left the factory with the smaller size factory tires. :)
 
Those RPMs are right where they should be for a Jeep running 31" tires. Lighter weight cars or cars with V8 engines don't require as high of an RPM. Your TJ's engine RPMs were higher than that when it left the factory with the smaller size factory tires. :)

Ok thx I was just a little worried that I was running it hard or something. Oh one more thing. I change gears at around 2 grand. Is that too low? too high?
 
...Oh one more thing. I change gears at around 2 grand. Is that too low? too high?
I typically shifted at a higher RPM than that when I had my 5-speed. Keep in mind that babying the engine by never revving it hard to high RPMs can cause a buildup of carbon in the combustion chambers. That will eventually degrade engine performance which can also make the engine start pinging from premature ignition caused by the carbon deposits. Your engine will thank you if you do the occasional full throttle acceleration to high engine RPMs to help blow the accumulated carbon deposits out when it is safe to do so. :)

Carbon buildup is actually a common problem in cars driven too conservatively... especially high performance engines where the owner is afraid to drive them as hard as they need to be occasionally. Corvette mechanics spend a lot of time repeatedly revving engines to high RPMs to clean out the carbon deposits to fix customer complaints of their engines not running right.
 
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I typically shifted at a higher RPM than that when I had my 5-speed. Keep in mind that babying the engine by never revving it hard to high RPMs can cause a buildup of carbon in the combustion chambers. That will eventually degrade engine performance which can also make the engine start pinging from premature ignition caused by the carbon deposits. Your engine will thank you if you do the occasional full throttle acceleration to high engine RPMs to help blow the accumulated carbon deposits out when it is safe to do so. :)

Carbon buildup is actually a common problem in cars driven too conservatively... especially high performance engines where the owner is afraid to drive them as hard as they need to be occasionally. Corvette mechanics spend a lot of time repeatedly revving engines to high RPMs to clean out the carbon deposits to fix customer complaints of their engines not running right.

What RPM do u shift at?
 
It's been probably 8 years since I converted my TJ from its 5-speed to an automatic so I don't recall exactly... but probably pretty close to the mid-high 2's to 3k around town, up to 4k or so when accelerating/merging onto a freeway.

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 :p