Yes.
Engine: Upgrade 3.8 to 3.6?
- Thread starter Dzine07
- Start date
Yes.
HAFICON
Adventurer
2012 JKU 4.88s, Auto, 34.some thing tires. It has lots of power and little MPG. That is not really a concern to me but just passing the word. I am in Ma. And RPM IS fine went ba k to Alabama and RPM was way way high... Lots of people say the 3.8 is fine, lots say it is not I personally have no say in it as I have not owned one.
The way I look at this is, the Jeep is not a race car, can you keep 50 mph up a big hill your good. sit back and enjoy the scenery. Run 4.10 gears with 35's and you will be fine. Nevermind what the gearing chart says. I am on 33's with 3.73s and its just fine. No, I wont win races, but I will get there, and have a huge friggin smile on my face when we jump out.....and in for that matter. I have 2" lift on mine now, and I am planing a 3.5" lift and 35. I will goto 4.10s then. Just for a little pop compared to keeping the 3.73s. Keep the milage as close to stock. I tow a 10ft pop up, and I get wherever I want to with it and my Jeep. I think American are now POWER OBSESSED. Everything these days is HP this and HP that. Same with motorcycles too. The adventure bikes with 150 plus HP, my versys does just fine with 60hp. Hauls My wife, and I with our gear around at well above legal speeds.
We are happy with our rig.
We are happy with our rig.
Cole
Expedition Leader
This was fine in 1950 when everything was this slow and the speed limit wasn't 75 mph. Today it is a pathetic excuse of an underpowered vehicle. Excuses for cheaping out on the engine and transmission like "it's not a race car" are flat out silly. Especially when every modern SUV drastically out performs it on road. No reason other then being cheap and lazy for this lack of performance.
My 2008 JKUR would not hold the 60MPH speed limit on many of our mountain roads here without banging the rev limiter all day long between the pathetic gear spread of the auto. Which would then return a whopping 5mpg!!! My 550HP SUV pulled the same roads in total relaxing comfort and gets 18mpg doing it.
Having more power isn't about "wining races". It's about driving in modern conditions safely and comfortably. It's about not being "that guy" holding everyone else up because YOU think 50mph in a 75 is "fine".
It's also about being able to do things a Jeep *should* be able to do! My 1980s Porsche has a higher tow rating than a 4 door Jeep(seriously). That is laughable! A Jeep should have the power to pull a real trailer!
Cole
Expedition Leader
Fwiw, here is a video a shot of my JKUR trying to maintain the speed limit of 60 mph on I70 between Silverthorn, Co and the tunnel.
I realize most people here think their Jeep is fine because they live in the low elevation flat lands. It may be *fine* there. I found it unacceptable for freeway travel here in the Rockies. (35s and 5:13s)
I know the video is a bit long, so here is the spoiler alert. Basically running against the rev limiter for 8 minutes in second gear to almost maintain the speed limit. (Traffic goes faster than the limit and if I had to slow down for any reason then I would be even more in the way) But, I do kinda narrate what is going on if you want to suffer through 8 minutes of it:coffeedrink:
I realize most people here think their Jeep is fine because they live in the low elevation flat lands. It may be *fine* there. I found it unacceptable for freeway travel here in the Rockies. (35s and 5:13s)
I know the video is a bit long, so here is the spoiler alert. Basically running against the rev limiter for 8 minutes in second gear to almost maintain the speed limit. (Traffic goes faster than the limit and if I had to slow down for any reason then I would be even more in the way) But, I do kinda narrate what is going on if you want to suffer through 8 minutes of it:coffeedrink:
Last edited:
toxicity_27
Adventurer
Yes, it was a huge leap. I couldn't stand the 2011, it was so slow it seemed like it couldn't even get out of it's way. I did get it on the highway, at speeds of 60+. It doesn't feel near as slow as the 3.8.
I owned an 07 that was really under geared (6spd). Was manageable, but frustrating. Bought a 2012 JKUR, and haven't looked back. The power and driveability is very noticeable.
However... if you're content with your current setup and just want to adjust to go to 35s, do a re-gear. Prices in the States seem to be pretty reasonable (from what I hear - around $1200). Not cheap, but will make a massive difference to the JK. The engine will still be the dog that it is... but if you're content with what you have now, it shouldn't be that much different after a regear and 35s.
My roommate has 4.10s and 35s on his 08 JKUR (auto) and needs to regear - it's just a lot more expensive up here (2k+).
brianjwilson
Some sort of lost...
I agree 100%. Some people don't get it. When you're driving up a pass at 8000'+ and you're nearly getting run over by truck/trailer combos it is unsafe. Or simply holding up lines of traffic on any significant hill. "It's a jeep not a race car" is a poor excuse. It is a modern vehicle and shouldn't be a hazard on the road. I didnt have complaints with the 3.6 rubicon six speed. Anything but fast compared to every other truck/SUV I've owned, but at least it maintained speed on the highway. I've always returned better mpg with vehicles that have excess power, because you don't have to rev the piss out of the engine to pull up a mountain pass or maintain speed. And it is far more relaxing to drive.
Zeep
Adventurer
Keep your warranty up to date with these new 6,7,8,9 speed tranny's. I bet they're remove and replace, because nobody will be able to diagnose or repair them properly!
Cole
Expedition Leader
What makes you think they are any less reliable than a 4 speed?
These companies don't just reinvent the wheel. They take a century of transmission manufacturing knowledge and build stuff that should have fewer flaws.
If you want 40 year old transmissions maybe you should stick with 40 year old cars.