3.8 vs 3.6

[TRLJNKY]

Run what I brung. The 3.8 is what I have and Ill make it work for as long as I can. Is it underpowered? Sure. I just slow roll and say f it. I still need to step up gears from 4.10's but Im not complaining. Would I prefer the 3.6? Without a doubt. Still love my Jeep

aka cavfighter

 

[Reso]

Traded my baby, 07 six speed, for a 2015 six speed. The interior and engine changes are 100% worth it. I would not hesitate to buy an 07-11 with the six speed at all, but the 3.6 is amazing!

 

[Maineiac]

I'm loving my 2 door 3.8 with 6 speed.. all stock Sahara. It moves along fine. I'm sure as I upgrade things I'll still be fine with gear changes to accommodate bigger tires and weight.

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[KSCRUDE]

My 11 3.8 which is a 2 door auto has more pep then I hardly ever need. But I put 4.88 gears in it shorty after I bought it new. It’s a Sahara on 32 inch rubber. The 4 speed auto is so high geared it is a dog even with 4.10 and stock rubber. I can cruse at 80 at around 2,900 rpm. Does well going through the Rockies on I 70. I usually drive in the 70 to 85 range. It is light with light tires. Would love a new 2 door JL but I built one on the Jeep site, and 52.5 K list price is crazy. With only 30 K on the Jeep I will just keep it as we have 7 vehicles, and most of them just sit, most the time. I’ll Waite for the new bronco and see what it looks like and pricing. You can’t even get the 4 banger turbo or the diesel in the 2 door yet. Would prefer the turbo, but not big on the hybrid crap. And if they ever do put the diesel in the 2 door it would be a $60K vehicle.[emoji79]


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[TomDabb]

My ‘13 3.6 pulls surprisingly fast. All stock and ‘33’s. My sons ‘08 3.8 does stand up in acceleration but at the end of the day, I’d rather drive the 3.8 if it has heat - head casting sand is killing my winter drive motivations. I feel I’ve almost done it all to fix it - heat isn’t an option last time I checked Chrysler.


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[spinned]

The 3.6 is a nice engine. I have a 2012 JK 2 door 6 speed with 48k and never a problem or even a warranty issue. I'm running 315/70r17 Duratracs (34s) with 4.56 gears. My JK has plenty of power in lower gears and cruises on the freeway still in the green zone. I think either engine would be fine... just get the nicest one you can find for the money. Not many bargains on jeeps in my neck of the woods.

If I were to do it again and buy a used JK, I might choose the rubi over an engine size... just for the front 44 and lockers, but that's only if I wanted a better snow/rock crawling setup. I'd bet most rubi owners in my town are more impressed with having a hood sticker than engaging the locker button. No disrespect intended. It's just that I see some of us that don't have them would like to use them, and those that have them don't. Ha.

 

[jsukey]

I love seeing all of the positive reviews across the spectrum! That just goes to show how true the love runs in all of us for our Jeeps! My '07 Sahara was ordered with the 6 speed manual and 4.10's. I ran them for a couple of years after I upgraded to 35" Nitto Trail Grapplers. I didn't feel it was a dog, but definitely left something to be desired. While some will disagree with my choice due to the smaller pinion, I picked up a pair of beefed up Rubi 44's with 5.38 gears. I was leaning towards 4.88's or 5.13's originally, but the price I paid for the pair of axles was simply too good to turn down. The front was sleeved, trussed, and gusseted...with LCA skids and RCV shafts. The rear had chromoly shafts. Both axles were low mileage with factory Rubi lockers, and had Yukon 5.38's with Riddler diff covers. Yes, that is a tall gear set for only having 35's! It doesn't bother me, as it isn't my everyday driver. I drive it to and from Barnwell Mountain, Hidden Falls, Bridgeport, and K2 and I yield around 13 mpg running 75-80 mph in my fully loaded 2 door. I never have to hunt for gears on the highway, and it performs great for me on the trail. If anything, I have found myself to be breaking less these days as my 1st and 2nd gear ratio are so low that I don't get too throttle happy or induce too much wheel spin, and/or hop. I was fortunate enough to happen across a 3.8 that didn't suffer from the dreaded oil blow by, so I have no real complaints. I would absolutely love to have the upgraded interior though! For now, I'm fit as a fiddle! A fiddle yearning for more! 37's are coming after the wedding ring is paid for! Happy Holidays to everyone!

 

[DanW]

My old 2008 3.8 has been a sweet engine. Sure, it's no powerhouse, but it has been adequate. I've got a 6 speed with 4.10 gears (Rubicon) and I run 33" pizza cutter KM2's. It does fine on the highway and off-road. Funny thing about that 3.8. It started using oil at about 40k, drinking up to 1 quart per 1,000 miles. It now has 120k miles and has decided to stop using oil. I noticed reduced consumption around 116,000 miles, going to 1/4 quart, then maybe 1/8. Yesterday, I checked it after another 1,000 miles and it had used zero oil! I don't get it, but this might be the first self-healing engine I've ever owned! Anyway, I drove a 2017 JK for a week that had 35's and a 4" lift with 3.73 gears and an auto. The 3.6 most certainly makes more power. I'm sure with a similar set up to my old JK, the difference would be night and day. I still love my old 3.8, though. I have a new JL Rubicon coming in January (hopefully), but I'm keeping the old JK. It is just too good to let go and I have the lifetime powertrain warranty. The Jeep runs and looks like new.

 

[DanW]

You need to rev the piss out the 3.6 to get the power.

No you don't. That's a common belief because the peak is at or over 400rpm. However, It gets over 90% of its torque at only 2000rpm. It has an incredibly flat torque curve. It pulls well and in a linear manner all the way through its power band. Torque peak doesn't tell the story. You have to look at the torque curve.

 

[RedRocker]

I have a 2007 JKU that started out life with the 3.8l auto trans. I then added a Sprintex supercharger and eventually swapped in an LS3 at about 120k miles. I have driven from Michigan to Utah 13 or 14 times now and even with the Sprintex the 3.8l really struggled to make it over the Rockies - I'm talking not even being able to hold 50mph and I thought I'd blow the engine. The only thing slower than me on the climbs were semi trucks. (37in BFGs which are really 35s and 4.88 gears).

My wife has a 2012 JKU Rubi with 3.6l and 4.10 gears, 33in KO2s. We took it to Utah this summer and it had no problem at all holding speed going over the Rockies fully loaded with 4 passengers.

 

[jsukey]

I had a similar experience as well. Burning a quart of oil every 1000-1500 miles. I decided to try swapping out the PCV valve, and that turned out to be the culprit. Sitting at 122k miles now, and it doesn't burn a drop between oil changes! I'm not mad though...I believe that's why I got the raging deal on a custom ordered Sahara with 4.10's, LSD in the rear, and factory half doors! It had never been modded or off-roaded when I bought it.

My old 2008 3.8 has been a sweet engine. Sure, it's no powerhouse, but it has been adequate. I've got a 6 speed with 4.10 gears (Rubicon) and I run 33" pizza cutter KM2's. It does fine on the highway and off-road. Funny thing about that 3.8. It started using oil at about 40k, drinking up to 1 quart per 1,000 miles. It now has 120k miles and has decided to stop using oil. I noticed reduced consumption around 116,000 miles, going to 1/4 quart, then maybe 1/8. Yesterday, I checked it after another 1,000 miles and it had used zero oil! I don't get it, but this might be the first self-healing engine I've ever owned! Anyway, I drove a 2017 JK for a week that had 35's and a 4" lift with 3.73 gears and an auto. The 3.6 most certainly makes more power. I'm sure with a similar set up to my old JK, the difference would be night and day. I still love my old 3.8, though. I have a new JL Rubicon coming in January (hopefully), but I'm keeping the old JK. It is just too good to let go and I have the lifetime powertrain warranty. The Jeep runs and looks like new.

 

[Reso]

No you don't. That's a common belief because the peak is at or over 400rpm. However, It gets over 90% of its torque at only 2000rpm. It has an incredibly flat torque curve. It pulls well and in a linear manner all the way through its power band. Torque peak doesn't tell the story. You have to look at the torque curve.

X2 I’ve had both and the 3.6 has a much better powerband all around.


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[Reso]

I had a similar experience as well. Burning a quart of oil every 1000-1500 miles. I decided to try swapping out the PCV valve, and that turned out to be the culprit. Sitting at 122k miles now, and it doesn't burn a drop between oil changes! I'm not mad though...I believe that's why I got the raging deal on a custom ordered Sahara with 4.10's, LSD in the rear, and factory half doors! It had never been modded or off-roaded when I bought it.

I changed the PCV twice on my 07 and still burned almost 2 quarts every 1000 miles.


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[jsukey]

Sounds like you were victim to the 3.8 with poorly installed piston rings from the factory. Happened to a lot of folks. I figured that was my issue as well, but decided it wouldn't hurt to change it just to see. Glad I did! Too bad the previous owner didn't think to try that!

I changed the PCV twice on my 07 and still burned almost 2 quarts every 1000 miles.


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