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2500 RPM OK for 8 hours?

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6.1K views 44 replies 34 participants last post by  95cherokeeSE  
#1 ·
Going on a long summer road trip and was wondering if a 1999 4.0 TJ was OK to cruise at a 2500 RPM all day? That is about 70 MPH in my Jeep with 3.73 diffs on 31x10.5 tires. I was curious if 2500 RPM was too high for 8 hours of driving over 4 days?
 
#2 ·
Hell yeah, I've driven 13 hours at that speed with no problems. You're golden! I know they're intended as off-road machines, but a Jeep is still a perfectly good highway vehicle. :thumbsup:
 
#3 ·
I drove my Rubicon with 4:10 gears and 31s back from WA to ND (2000+/- miles) at Interstate speeds (80+/-mph) with no concerns. I had also taken many trips with my 99 TJ (3:73 gears with 30's) at interstate speeds with no issues. I'm sure you'll be fine. Jeep built them to drive on the highway as well as off road.
 
#10 ·
I dunno, what's the redline on a 4.0 again?
 
#14 ·
The engine's no louder then any other car, it's just that there's nothing in there to dampen the sound. You're getting raw, unadulterated engine noise there. :D

Although that explains your apprehension. Don't worry if it gets loud, that's just how a TJ rolls. Just keep it below the redline and you're golden. :thumbsup:

EDIT: But make sure you've got the hard top if you want to drive that far. I did a 2 hour trip at about 120 KPH, and the soft top damn near made my ears explode. When I got up to 140 KPH to pass a truck, it felt like I was inside the kick drum at a death metal concert, it was so loud.
 
#15 ·
2500 rpm is optimal. You are perfectly geared for driving that speed and should get maximum highway mpg with that combo of gear, tire size and rpm plus have some passing/climbing power.

Someone else said that the Wrangler is a perfectly good highway vehicle. Not really. I drove about 2000 highway miles in my TJ last month and it sucked. With speed limits of 75 and 80 mph and traffic moving at 85mph, it felt like I had exactly the wrong vehicle for that kind of driving. We had the stereo on the highest setting and could still barely hear it over the road noise. We drove through a couple of thunderstorms and the wind felt like it was going to rip the soft top off or push us off the road. Driveline vibes at various speeds. Poor gas mileage. If I could pick any vehicle to drive 2000 miles on the highway an Jeep Wrangler would be one of my last choices. I love my Jeep but for thousand-mile-interstate-highway-drives it is much less than ideal.
 
#19 ·
...Someone else said that the Wrangler is a perfectly good highway vehicle. Not really. I drove about 2000 highway miles in my TJ last month and it sucked. With speed limits of 75 and 80 mph and traffic moving at 85mph, it felt like I had exactly the wrong vehicle for that kind of driving...
This is a matter of perception. I rode Harleys for over 30 years and put in numerous multiple thousand mile cross country trips, too many to even begin to try and count. Compared to that, the TJ is pure luxury. Good grief, it has a windshield, heater, A/C, massive storage, cruise control, spare tire, radio, top/doors (well they are available even if not used all the time), no requirement to wear a helmet, no bugs in the teeth, no need to worry about the horses in the the trailer ahead of you deciding to urinate,... What more could you ask for in a cross county vehicle?
 
#16 ·
With your stock drive train and 31" tires, any RPM that gives you a legal speed in 5th gear is perfectly fine. The engine you are running has been around for decades and is a good one for both highway and off-road use. Enjoy the trip. Quit over-thinking things (this will make the "enjoy the trip" a lot easier).
 
#17 ·
Well, to be fair, I mean that it's perfectly safe to drive at highway speeds, as opposed to other offroad-oriented vehicles, like Unimogs or something. It's not terribly comfortable (Although I honestly enjoy my TJ more on highway trips then my parent's old Crown Victoria, because the TJ keep you awake and on your toes.)
 
#18 ·
As long as the tach isn't redlined you can run it all day as long as your not over heating.

I drove mine from Michigan to Wyoming in 22 hours last month only stopping for gas and bathroom breaks. It took it like a champ.

Just check all of your fluids before the road trip, you'll be fine. Good time to check your tire pressure to.
 
#23 ·
MDM, I could have written that one too, but you forgot 1 major thing. You don't have to put your foot down when you stop. OP, I ran 32's for a short time after i regeared from 3.73 to 4.56, 70 to 80 was fine. Like several have said just keep it under the redline, which would be much faster than you would ever want to go in a jeep anyway.
 
#25 ·
The Jeep TJ is not the most comfortable vehicle for long driving purposes. That said, it is certainly capable of prolonged distances.
A buddy (owns 2005 Rubicon) and I (2000 TJ) drove from Toronto to Moab and back during a 3 week vacation. A road trip to Moab requires that you to drive your Jeep.
 
#26 ·
That's about the same as our trip. We drove from Houston to Big Water, Utah where we finally got offroad in the canyons of Glen Canyon National Rec Area and Grand Staircase. The 2000 miles of highway blew but the 500 trail miles made it all worthwhile. We're going back next year and I wish we could figure out a way to get my Jeep there without having to drive it half way across the United States. Only other options I can figure is to pull it behind an RV or fly out there and rent a 4WD Jeep. I wouldn't be real comfortable wheeling an unfamililar rig though plus it costs a fortune.
 
#29 ·
I frequent 5 hour trips to and from school. With 3.07's and 30.5 tires, rpms are above 2k all the time (doing 70-75) The jeep never has had any problems with heat in the summer, just the Soft top used to be loud as hell! When the old one tore, I got a Bestop Replaceatop with sailcloth, Best thing ever invented! I can now not go deaf after driving on the highway for extended periods and even hear my radio!
 
#31 ·
I hate people that drive 85 in a 70, it's inconsiderate to blow the speed limit by 15+. That being said, I routinely take 5 hour non-stop trips in my Jeep to reach my camping grounds, and I'm turning 2800 RPM at 70 (4.56 on 33's). Even with a winch blocking the radiator, I don't go above 210

JeffB: great name :D I hear ya, the Jeep isn't the best hwy vehicle. That being said, full doors, a sailcloth top, and keeping your speed between 60 and 70 go a loooooong way towards making the vehicle more tolerable on long trips. Even I start hating my jeep when I make a rare attempt to join the inconsiderate testosterone over-dosed crowd at higher speeds.
 
#32 ·
thread surprises me, I drove a 95 YJ almost 100,000 miles with a soft top in Wisconsin many trips to MPLS - Madison. Never cold, not too loud. That Jeep was a manual, 4.0 with 31's My current Wrangler is a 2001 4.0 manual, 3.73 with 31's with 175,000 miles and that jeep has driven cross country many times even drove from Tucson to Acapulco. More than one trip from Nogales AZ to MPLS MN. One long trip I drove was Nogales AZ to Jacsonville FL. I am currently rebuilding this jeep and going to up in tire size, I would guess that as you go up in tire size and the required mods to run bigger tires the long cross country trips would be more tasking. But a "for the most part stock" jeep running 31's it should be easy to drive anyplace paved you want.