Newbie, lessons learned on a road trip with the 3.8 with 6-speed manual and soft top

[72c10]

Just completed a 300 mile (each way trip) with my '07 JKU X with the 3.8l, 6 speed and soft top. Here are the lessons learned if you were like me and studied the Wranglers before you bought or just bought yours.

Bought my JKU with 118,500 mi used as a 3rd vehicle to putt around on weekends. We went to St. George, Utah a few weeks ago and thought "damn, the jeep would've been fun to bring down", due to the availability of fun trails, sand, etc. that you can just take the jeep to in a matter of 5-10 minutes around there (Sand Hollow, desert, Top of the World and other damn good trails). So, we did... As listed above, my specs listed were my concern - the 3.8 matched with a manual transmission with 32" tires (255/75r17) BFG KMs with the 3.21 rear end/gears and a damn SOFT TOP. Before we get to the end, I'll tell you right now that the loud ass noise at 70-80mph was worth taking it down, as well as the struggles to find the right gears when climbing 2000 plus feet of elevation a few times in the trip and only being able to go 70 to 80 mph.

1. Soft top is loud as hell, but I could still hear the stock stereo (bluetooth adapter) and could barely hear my 2.5yo twins whining

2. When going up hills and trying to maintain at least 70 - 75mph, I had to gear down to 4th gear sometimes... keeping the RPMs at about 2,900 to 3,000. Question: that's not bad is it? I figured I was wayyyyy away from the redline. 5th gear was sufficient if you gassed it when in 6th gear, before going up the hill.

3. 3.21 gears SUCK, but I could always regear or just get 265/70r17 tires next time and it may help, without spending $1200 - 1500 to regear. Or I can just regear... or buy a jeep with at least 3.73 gears. At the end of the day, still love this jeep.

4. I didn't burn oil... freaking love it.

5. Remember to air down when hitting the trail... I forgot, but quickly got out of deep sand when I aired down to about 20psi on the BFG KMs.

6. Cruise control: try to get cruise control. Mine X doesn't have it, so if you don't... have a good foot massage therapist at the end of your trip

Questions:

1. Would a hard top help with the wind noise? My friend has an '18 American Fastbacks Jeep JKU and he said that his was loud on the same trip. Would a factory one be quieter?

2. It won't harm the engine if I'm rocking 3,000 rpm for a mile or two on an incline, will it? I didn't burn oil, my temp stayed below half, I felt good torque.


This is an FYI and my learning process (the questions). At the end of the trip - I like my jeep even more. It's fortunate I have a badass wife that doesn't mind the noise or utilitarian road trip (we take our comfy car usually).

 

[BLACKJKU]

The drive by wire on these makes acceleration really slow, I have a Pedal Commander on my Jk and it really improves the throttle response. Not sure if that would help with the hills or not, I pretty much live in the flat lands.

As long as your not getting the engine temp to hot then running at those RPM's then it should be ok.

 

[Eulalio]

Just completed a 300 mile (each way trip) with my '07 JKU X with the 3.8l, 6 speed and soft top. Here are the lessons learned if you were like me and studied the Wranglers before you bought or just bought yours.

Bought my JKU with 118,500 mi used as a 3rd vehicle to putt around on weekends. We went to St. George, Utah a few weeks ago and thought "damn, the jeep would've been fun to bring down", due to the availability of fun trails, sand, etc. that you can just take the jeep to in a matter of 5-10 minutes around there (Sand Hollow, desert, Top of the World and other damn good trails). So, we did... As listed above, my specs listed were my concern - the 3.8 matched with a manual transmission with 32" tires (255/75r17) BFG KMs with the 3.21 rear end/gears and a damn SOFT TOP. Before we get to the end, I'll tell you right now that the loud ass noise at 70-80mph was worth taking it down, as well as the struggles to find the right gears when climbing 2000 plus feet of elevation a few times in the trip and only being able to go 70 to 80 mph.

1. Soft top is loud as hell, but I could still hear the stock stereo (bluetooth adapter) and could barely hear my 2.5yo twins whining

2. When going up hills and trying to maintain at least 70 - 75mph, I had to gear down to 4th gear sometimes... keeping the RPMs at about 2,900 to 3,000. Question: that's not bad is it? I figured I was wayyyyy away from the redline. 5th gear was sufficient if you gassed it when in 6th gear, before going up the hill.

3. 3.21 gears SUCK, but I could always regear or just get 265/70r17 tires next time and it may help, without spending $1200 - 1500 to regear. Or I can just regear... or buy a jeep with at least 3.73 gears. At the end of the day, still love this jeep.

4. I didn't burn oil... freaking love it.

5. Remember to air down when hitting the trail... I forgot, but quickly got out of deep sand when I aired down to about 20psi on the BFG KMs.

6. Cruise control: try to get cruise control. Mine X doesn't have it, so if you don't... have a good foot massage therapist at the end of your trip

Questions:

1. Would a hard top help with the wind noise? My friend has an '18 American Fastbacks Jeep JKU and he said that his was loud on the same trip. Would a factory one be quieter?

2. It won't harm the engine if I'm rocking 3,000 rpm for a mile or two on an incline, will it? I didn't burn oil, my temp stayed below half, I felt good torque.


This is an FYI and my learning process (the questions). At the end of the trip - I like my jeep even more. It's fortunate I have a badass wife that doesn't mind the noise or utilitarian road trip (we take our comfy car usually).

View attachment 117126

1st: You are just a whiner.
2nd: I like your wife better than you!
Why do you want 80 mph from a Wrangler anyway?
3rd: Suck it up and enjoy having a Wrangler. It's a love and hate relationship. Can't live with it and cannot live without it.

 

[Mr. Bi-Polar]

Congrads on not burning oil as our last 3.8L wrangler did on a very long trip. As for the gears, Yes 3.73 is going to be way better for you. We run 3.73 from the factory with 17x8.5 wheels and (285/75/17) 34'' x 11.6 Nitto tires. 85 mph up hill is nothing to this jeep. Not that I like those types of speeds, But It can shit and kick it when I need it too. As for the hard top, I've tried to support you questions in another area. the hard top will significantly reduce the wind noise, but it will also add weight to the jeep. So re-gearing is going to be critical.

As part of the awareness, I'd flush the coolant make sure you burp the system afterwards, Prop the jeep up hill when you do the flush. Check the control arms, drag link, tie rod and track bars as these are going to create issue for you if not kept in check. Check what we're having to deal with now and something we'll be correcting within the next 2 weeks.

Jeep Wrangler JK Suspension Performance Diagnostic Guide

Suspension problems are some of the most difficult to pinpoint because they can appear as many different issues and emanate from virtually anywhere under your hood or under your Jeep itself. From an annoying squeaking sound to a vibration or the infamous death wobble, the suspension in your Jeep...

wranglerjkforum.net

 

[72c10]

The drive by wire on these makes acceleration really slow, I have a Pedal Commander on my Jk and it really improves the throttle response. Not sure if that would help with the hills or not, I pretty much live in the flat lands.

As long as your not getting the engine temp to hot then running at those RPM's then it should be ok.

I actually thought of the Pedal Commander on the way home. It would considerably help to get the momentum before you downshift and get up the hill. There are some cheaper ones out there, but I think I'd stick with something more reputable.

 

[72c10]

1st: You are just a whiner.
2nd: I like your wife better than you!
Why do you want 80 mph from a Wrangler anyway?
3rd: Suck it up and enjoy having a Wrangler. It's a love and hate relationship. Can't live with it and cannot live without it.

1. Screw you! . I am whining, but I DID SAY - I like my Jeep more after the trip.

2. My wife is better looking than me, so I agree with you. 80mph is a norm here in Utah on the interstate, I still got passed by.... Everyone. But, who cares - my trip is way more fun than theirs - except for the effing OTHER JEEPS passing me .

3. I've had this jeep for 3 months and I love this thing. I'm getting the whole "love/hate" things now.

4. I love that Jeep owners are so helpful with their experiences that is therapeutic for my OCD ass.... "Rattle", pshhhh, it's a Jeep thing - OK, I sleep better at night!

 

[72c10]

Congrads on not burning oil as our last 3.8L wrangler did on a very long trip. As for the gears, Yes 3.73 is going to be way better for you. We run 3.73 from the factory with 17x8.5 wheels and (285/75/17) 34'' x 11.6 Nitto tires. 85 mph up hill is nothing to this jeep. Not that I like those types of speeds, But It can shit and kick it when I need it too. As for the hard top, I've tried to support you questions in another area. the hard top will significantly reduce the wind noise, but it will also add weight to the jeep. So re-gearing is going to be critical.

As part of the awareness, I'd flush the coolant make sure you burp the system afterwards, Prop the jeep up hill when you do the flush. Check the control arms, drag link, tie rod and track bars as these are going to create issue for you if not kept in check. Check what we're having to deal with now and something we'll be correcting within the next 2 weeks.

Jeep Wrangler JK Suspension Performance Diagnostic Guide

Suspension problems are some of the most difficult to pinpoint because they can appear as many different issues and emanate from virtually anywhere under your hood or under your Jeep itself. From an annoying squeaking sound to a vibration or the infamous death wobble, the suspension in your Jeep...

wranglerjkforum.net

on the tips. Thank you. I'll be sure to do a once over on it. When I purchased it and got the rims/tires/suspension installed, I had those guys check to make sure of the front end, due to death wobble stories. He said that the PO actually installed a beefier stabilizer bar and shock. I'll make sure I periodically check it.

 

[Eulalio]

Maybe you need a good tune-up as well.
Hard top is very inconvenient if you like to take the top down on good weathers.

 

[Mr. Bi-Polar]

Good to hear @72c10 I was hoping that the factory setup would last but didn't after 2 years of driving. Then I was hoping the Moog setup would hold but it didn't either. This time, I'm not messing around and I'll be going full bore with the Metalcloak 1 ton setup.

As for the gearing. We made sure when we special ordered the jeep it has the regears. I was juts a bit concerned with the tires and I'm still concerned with the actual width of the tires. otherwise you just need to pick the jeep over with a fine tooth comb as one does not know what the previous owner did to it.

Edit:

One thing I meant to say yesterday, was about the factory mud terrain tires. we've had a set on our last jeep and hated them cause they didn't last 28K miles. The reason for this is jeep mounted soft mud all terrain tires on their jeep to look "cool" but these tires are not ideal for the road and will wear out sooner then later. because the tires are a softer compound the will flex even if they're not aired down. even rotating them religiously didn't help the tire longevity. So upgrading the tires will also help with your fuel economy. Even having a second set just for the road would help. We've driven the jeep for almost 4 years now and have yet to encounter snow. So we're hoping to have the steering completed before the snow and will give our thoughts about the Nitto tires there after.

 

[JerryD]

When I finally broke down & bought a hardtop (factory) for my '08, noise was drastically down. No idea on aftermarket ones. On my current ('16) I have Mopar headliners which help even more. I do not have the underhood sound insulation material. I have soft & hard tops (and a bikini too) and swap them out seasonally. Much more comfortable in Michigan Winters with the hardtop.

Revving at 3k isn't a big deal especially for a shorter duration.

Glad you're enjoying it

 

[Chris]

1) A factory hard top makes a tremendous difference with wind noise. I also wear ear plugs when I drive mine with no top, which makes a huge difference as well.

2) No, that won't harm the engine at all. In fact, that's where you should be keeping the engine the majority of the time. It's not good to lug the engine at 2K RPMs and lower.

 

[Whitesandstitan]

Congrats on the Jeep!

I am surprised that I didn't read it in here yet, so I will mention it.

Re-gearing your Jeep will in no way give you more highway speed. If you go 35's and regear appropriately you may still hit 80 if your lucky.

You will have to dump the 3.8 and tranny to do better unfortunately. This is what you get with the 3.8 drive train with over 100k

 

[JerryD]

Regearing won't give you more speed, it'll just put the powerband where you want it, whether it's off the line or at top end - to a point

 

[72c10]

Congrats on the Jeep!

I am surprised that I didn't read it in here yet, so I will mention it.

Re-gearing your Jeep will in no way give you more highway speed. If you go 35's and regear appropriately you may still hit 80 if your lucky.

You will have to dump the 3.8 and tranny to do better unfortunately. This is what you get with the 3.8 drive train with over 100k

Great to know, thank you! But, I will keep it regardless (unless it's for a newer one). This JKU proved itself to me... it's starting to feel like a great wife: may have its quirks, but damn- I'll ride it every day (if I didn't have a work car!)

 

[Eulalio]

Topless wife is always good to ride on in my book.
Edit: Topless jeep

 

[blank]

for your top try turning on the recirculation button and watch the soft windows and once they suck in turn off the recirculation and watch the top swell with air. that will help with noise some what.

 

[72c10]

I actually thought of the Pedal Commander on the way home. It would considerably help to get the momentum before you downshift and get up the hill. There are some cheaper ones out there, but I think I'd stick with something more reputable.

@BLACKJKU - Thank you for hurrying my decision on the Pedal Commander. Got it and installed it within 30 min of deliver. NIGHT AND DAY difference. The City setting alone should’ve been what came from the factory. Up hills, merging into traffic, starts from stop lights and every which way just makes me LOVE this Jeep even more now. This PC exposes a good amount of potential these 3.8’s have in torque and hp. As of now, I do not feel the need to regear or modify the ECU to squeeze out HP/Torque.


The Bluetooth control from your phone is irreplaceable, since I did not want it exposed to thieves or weather when I have the top off.

I hope Santa brings the inventor of the PC something good for Christmas this year. Even tho I paid $250 (BF Sale), I feel like it’s worth every damn penny.

 

[BLACKJKU]

Told you it was a good investment, makes it feel like a whole new JK. Now just put on a Viper TB, long tube headers and high flow cats, with a Hypertech tune and you'll really wake it up.

I leave mine in the City most of the time unless I really feel like a gear head then kick it up a setting or 2.

 

[JerryD]

Don't mean to hijack but It's been a while since I looked at pedal commander (well, since I got a 3.6 jk). I remember people saying it really woke up the 3.8, but what was the concensus on the 3.6. IIRC (dangerous, I know), the ROI wasn't so great for the Pentastar - or am I mistaken? Anyone know?

 

[72c10]

Don't mean to hijack but It's been a while since I looked at pedal commander (well, since I got a 3.6 jk). I remember people saying it really woke up the 3.8, but what was the concensus on the 3.6. IIRC (dangerous, I know), the ROI wasn't so great for the Pentastar - or am I mistaken? Anyone know?

I don’t have the 3.6, but I can tell you from reviews from multiple sites... believe me - I looked before dropping the cash on one, 99% love it. A lot of them also used the PC on their Chargers, Durangos, Rams, GCs and other ones that have the 3.6.

I’ve only seen a couple that complain about going into Limp Mode. I believe they tried to use cruise control in ECO mode, which states in the instructions NOT to do. I also read of some people’s accelerator not working, but they could’ve reset it themselves. I wonder if it’s because they did not let the car stay off for 5 minutes to allow the electrical system to fully shut down and/or leave the key fob at least 35 away during install.
Overall, I’ve seen way more positive reviews (mostly 4 or 5 stars). If/when I get a newer one - I’d install it in any model Wrangler. - just because now I know what it can do. I’ll update if something goes wrong.

@BLACKJKU - have you had any issues? How long have you had yours?