3.6L with 6 speed MT has uneven power band

David F.

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Have a 2018 with about 8K on it. Have been having issues with an uneven power band while accelerating. I can feel it most when getting into 2nd from a turn around a corner. What I feel is that I turn with the clutch in and no gas. While letting the clutch out and giving the JL gas, I basically have no power. After about 1-2 seconds, then I can feel the power kick in and I am able to accelerate. Also, while accelerating getting onto the freeway, I can feel sluggishness.

Took it to the dealer yesterday and of course the response was that the tech could find nothing wrong with my JL.

Just really makes it not so much fun to drive.

Wondering if anyone else is experiencing something similar.
I get the same sometimes, I am just not used to all the city driving I do so I miss my "RPM window" sometimes. It took me 4K miles (don't laugh, it was years between my manual vehicles) to really get used to this but now I feel confident and this doesn't happen much. I threw on a cold air intake and a throttle body spacer that makes it sound mean at 2500 RPMS too so that also helps. I rev until I hear the growl then I know I am where she wants me to be... make sense?

Be a little more aggressive, sometimes they like that...



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WildCatguy

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I have this same issue, I have a 3.6 MT w/35's. I figured it was due to my 35's and need to regear.

My 6th gear is non existent on the highway, I can use 5th gear over 70 MPH, 60-70 MPH 4th gear.

If I regear should it solve the issue?
 

Rogues Gambit

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I have this same issue, I have a 3.6 MT w/35's. I figured it was due to my 35's and need to regear.

My 6th gear is non existent on the highway, I can use 5th gear over 70 MPH, 60-70 MPH 4th gear.

If I regear should it solve the issue?
Yes
 

Dave26

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So just to clear it up, will regearing solve the uneven power band issue (no power below about 1800 rpm) or just let you use 5th and 6th more on the freeway. I have 37’s on my Jeep and was going to have it regeared in hopes of solving the loss of power below 1800 rpm or so.
 

offset_98

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So just to clear it up, will regearing solve the uneven power band issue (no power below about 1800 rpm) or just let you use 5th and 6th more on the freeway. I have 37’s on my Jeep and was going to have it regeared in hopes of solving the loss of power below 1800 rpm or so.
No power under 1800 is a function of the engine, not the gearing or transmission.
 

Rufus

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Way I dive mine is -
If the rpm is below 2000 rpm
I downshift
In any condition expect maybe flat highway
6sp rubi 35 toyo mt's
I agree, it tends to lug under 2k. 6 spd Sport, stock.
 

8flat

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JLUR 3.6 MT 6-speed. So frustrated at this no-torque engine, when I go to pass someone on the highway I shift from sixth straight to THIRD gear, and floor it.

Then it finally, finally makes power. haha

6th to 3rd to 6th
 

alphalife9

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I agree there's not much torque down low but that doesn't address the uneven power delivery. I feel that too and am pretty sure it's "normal" unfortunately. I think it's the variable valve timing / intake adjusting for changes in loads throughout the powerband. It seems like it "steps" its changes and does so in a delayed fashion which leads to the weird inconsistent power delivery.
 

8flat

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I agree there's not much torque down low but that doesn't address the uneven power delivery. I feel that too and am pretty sure it's "normal" unfortunately. I think it's the variable valve timing / intake adjusting for changes in loads throughout the powerband. It seems like it "steps" its changes and does so in a delayed fashion which leads to the weird inconsistent power delivery.
Yeah it seems like there may be something wrong there. Mine is pretty smooth, albeit slow. haha. I'll try it again and pay really close attention, but from what I recall the only issue I've had with uneven power delivery is when the engine is lugging, it will surge a little bit, but that's almost normal for any small engine that's getting lugged at low RPM. And obviously it's not smart to lug an engine anyway, so I don't really do it much at all. Sometimes when starting out in 2nd from a rolling stop through an intersection, that's about it.
 

callerys

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The diablosport pcm and programmer made a huge difference. While not a lot of power below 2k the acceleration and highway driving is a world of difference.

Mine is a 6 speed rubicon on factory tires but i also live at 6300ft and the altitude kills power.
 

signals34

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i have the 3.6 manual., rubicon....i keep it in the 3-4000 range, no issues at all...no sluggish feeling at all....my hummer h-3 , 5 sp is also the same...have to keep it in the 3-4ooo rpm range, and it feels great....on the rubicon, if i do go up a shift to early, 1500-2000 range, it will drag.....
 

vavaroutsos

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I have a new 2019 with the 3.6 and manual. I don't expect a 3.6 engine to have much torque at 1500 to 2000 rpm's. I have ridden motorcycles all my life and smaller engines in heavy vehicles need a few more rpm's. I am used to the engine power band and gears after 1500 miles. I took one hwy trip for a couple of hundred miles and agree a little that hills present a challenge depending on posted/actual speed. But, 5th gear handled almost anything in the midwest::) It is geared for EPA mileage, which I got a little over 25 at 72 mph on my short trip. I'll take it.

I also had a rental for some dealer items and had the 8 speed for a couple days. Nice trans, but I watched the rpm's and it down shifts alot on the hwy. A little easier to drive because you don't need to be engaged, but the engine still needs rpm's to move the JLU at the slightest incline. I still prefer my manual because I feel a connection to the vehicle.
Totally agree with this. I had a rental 3.6L with 8-speed auto and was surprised at how often it down shifted and how high it let the engine rev. You need to drive the manual the same way. The engine is happy to rev and fuel economy doesn't drop much unless you put the pedal to the floor. I'm averaging over 22 MPG mixed with my manual and I drive back and forth over an 1800 ft elevation change every day.
 

urr2slo

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The new JL clutch is a twin disc dual mass flywheel design. Poor choice and design by Jeep engineers. I worked with Centerforce to prototype and develop an upgrade as I’m adding a supercharger and I wanted to make sure I had a clutch that would hold the additional power. The new clutch is a single disc design with a heavier flywheel, the additional weight and the fact that it’s Not a dual mass flywheel allows the power to be applied smoothly due to improved inertia. Since installing the new clutch it’s eliminated the flat spots in the power band, has greatly improved clutch feel, a huge improvement in traffic and city driving and much improved crawling. It has made it so much nicer to drive.
To address a few other concerns, it’s still gutless below 2500 rpm, and with 35 or 37” tires 6th gear is still useless. I will be installing and regearing as well as installing the supercharger in the very near future.
 

HeavyUser

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Power kicks in around 2k rpm with the 3.6, this is normal and to be expected. Start shifting higher up in the rev band, this is what I do and I have no problems.
 








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