Reality Check Needed

[Lionel Hutz]

I'm looking for some opinions on the numbers from a recent roadtrip and the conditions I was driving in. Went on a 700 mile roadtrip through lower northern Michigan and temps were in the mid-teens and winds were high. At times I could barely keep the Jeep in my lane on the freeway because the gusts were so strong. I'd have the top center of the wheel at 10 or 2, depending on the wind direction, to keep it in the lane.

I'm running the 3.6L (no etorque) on 37s with 4.56s. During the the freeway stretches the Jeep was constantly between shifting between 7 and 8th gear with the occasional dip to 6 if there was more of a grade on 75. The headwind was some of the worse I've driven in. Average mileage for the entire trip was in the low to mid 16s. I'm less concerned with the mileage as I am with the constant shifting of the transmission. Given the weather conditions, is this normal behavior on the 8speed auto, or is it at all worth considering 4.88s?

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[blnewt]

Driving essentially a railroad boxcar down the road in heavy wind is a beast w/ these things, even worse if you had a 2dr. It's perfectly normal. I've been blown into the oncoming lane here in New Mexico when winds get up to 70 mph, it's white knuckle time for sure. If your caster isn't at least 6 I'd address that, other than that just hang on!!

Transmission behavior is normal, just be glad you have such a great AT, I wouldn't worry about that.
Your 4.56 gearset should be just fine, just need to realize those rare conditions when the overall drive is going to suck

 

[Lionel Hutz]

Driving essentially a railroad boxcar down the road in heavy wind is a beast w/ these things, even worse if you had a 2dr. It's perfectly normal. I've been blown into the oncoming lane here in New Mexico when winds get up to 70 mph, it's white knuckle time for sure. If your caster isn't at least 6 I'd address that, other than that just hang on!!

Thanks for the feedback. On the rare instance I can find a smooth stretch of road in Michigan the Jeep tracks straight as can be. It was definitely white knuckle at times.

 

[JEEP4U]

Past experience dictates, if you would like to continue to utilize 37" tires 5.13 gear set is best. This will allow the use of all 8 forward gears. Some will say 4.88 is good enough with an Auto. This has just not been my experience, with head winds and elevation.

But, 70 mph winds......will give you quite the ride

 

[blnewt]

Thanks for the feedback. On the rare instance I can find a smooth stretch of road in Michigan the Jeep tracks straight as can be. It was definitely white knuckle at times.

Did you get the newer cast iron steering gear box? I had mine changed out and it did help, but my steering was fine until it got really hot, so that's not the case w/ you. But I would still consider having that looked into if you still have the aluminum box. This doesn't really apply to any wind related issues, but mainly just a bump up in better steering behavior.

 

[Lionel Hutz]

Did you get the newer cast iron steering gear box? I had mine changed out and it did help, but my steering was fine until it got really hot, so that's not the case w/ you. But I would still consider having that looked into if you still have the aluminum box.

I do have the new steering box.

 

[OBD]

From the way my new bone stock Willys drives, I would say, with your mods, your experience is about what I would expect.

 

[Lionel Hutz]

Past experience dictates, if you would like to continue to utilize 37" tires 5.13 gear set is best. This will allow the use of all 8 forward gears. Some will say 4.88 is good enough with an Auto. This has just not been my experience, with head winds and elevation.

But, 70 mph winds......will give you quite the ride

The winds weren't quite that high, but steady in the high 20s and gusts to 40-50mph. On the trip home it was a partial headwind.

 

[John VonJeep]

That all seems perfectly normal for a JL on 37s with 4.56 gears.

 

[JEEP4U]

High 20mph winds, should not give too many issues. Assuming your suspension/steering are sound. I would look at the front end alignment and /or tires.

 

[blnewt]

The winds weren't quite that high, but steady in the high 20s and gusts to 40-50mph. On the trip home it was a partial headwind.

Ours is a 2dr w/ a Rubicon lift and 295/70s (33.5" high), so having those tall bad-ass 37s and more lift will turn your boxcar into a double decker bus compared to our short 2dr. I'd imagine that was not a fun time at all

There's times we decide to leave our Jeep at home when the wind warnings get way up there. It's getting to be windy season here so we always check the weather before planning any extended drives, just not worth it to be miserable for 6+ hrs on the road

I love the hell out of our little mountain goat, but that wind can be a huge buzzkill

 

[zouch]

i might have missed it, but i didn't see any mention of what kinds of speeds you're talking about, or what kind of MPG you usually get.
the MPG on these things just falls off a cliff as you get up near and above 70MPH.
considering a final drive ratio like yours, a vehicle with all the aerodynamics of a barn door, and high winds, and i expect you're doing OK. the transmission? just doing its job.

I'm looking for some opinions on the numbers from a recent roadtrip and the conditions I was driving in. Went on a 700 mile roadtrip through lower northern Michigan and temps were in the mid-teens and winds were high. At times I could barely keep the Jeep in my lane on the freeway because the gusts were so strong. I'd have the top center of the wheel at 10 or 2, depending on the wind direction, to keep it in the lane.

I'm running the 3.6L (no etorque) on 37s with 4.56s. During the the freeway stretches the Jeep was constantly between shifting between 7 and 8th gear with the occasional dip to 6 if there was more of a grade on 75. The headwind was some of the worse I've driven in. Average mileage for the entire trip was in the low to mid 16s. I'm less concerned with the mileage as I am with the constant shifting of the transmission. Given the weather conditions, is this normal behavior on the 8speed auto, or is it at all worth considering 4.88s?

 

[Yogi]

Other than fuel consumption and extra tire wear, it's not a steady wind that bothers you. It's the gusts and then the lulls when you drive past a wood lot, or large building, etc. Turns an every day drive into a sporting event ... LOL

 

[Lionel Hutz]

i might have missed it, but i didn't see any mention of what kinds of speeds you're talking about, or what kind of MPG you usually get.
the MPG on these things just falls off a cliff as you get up near and above 70MPH.
considering a final drive ratio like yours, a vehicle with all the aerodynamics of a barn door, and high winds, and i expect you're doing OK. the transmission? just doing its job.

I kept it right around 70-73. Any faster and it didn't feel safe. The stretch of 75 has speed limit of 75, but it didn't feel like I could comfortably keep up with traffic. Winter mileage is usually in the 16s and during the summer I can get closer to 18 with easy driving.

My first thought about the transmission is that it can't be good for it to keep shifting between 7 and 8 so often.

 

[blnewt]

My first thought about the transmission is that it can't be good for it to keep shifting between 7 and 8 so often.

They're designed for shifting often, if you want to just keep a steady gear switch to manual mode and go down to 7 or even 6 and run a bit higher rpm. The ZF8 transmissions are extremely high quality units, I wouldn't worry about gear hunting, it's doing what it's engineered to do.

FWIW there's debate on the ATF being a lifetime fill. My 2cents is getting it serviced at regular intervals will make that lifetime much longer, and I want to keep this well past the FCA warranty "lifetime" for sure! A 50k mile service is my plan

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