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Discussion Starter · #1 ·
Hey guys and gals,

So my '08 JKU Automatic is having trouble downshifting into 1st gear on steep hill climbs while I'm in Low Range and in Drive. I have to manually shift into 1st on super steep ascents or the engine starts bogging down and lugging hard.
After asking around, I was told that you should always drive "manual style" whenever driving a JK automatic in low range.
Does anyone else do this?
My mechanic says that it's probably because the electronics in the tranny isn't communicating the downshift and that he has seen this before.
The fluid is fairly clean and at the right level.
 

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Absolutely use manual shift offroad with an automatic!

Also are you properly geared for your tire size - this helps immensely as well. Especially with that 3.8 engine it needs all the help it can get.
 
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I suppose many people change to tires outside their gear range and create this problem for their Jeeps knowingly. Then when they get offroad it happens.
 
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If you are crawling in 4L definitely shift manually.
 
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Yes, manually keep it in 1st when offroad on steep hill climbs. When the trans tries to shift to second, you lose momentum. I have seen MULTIPLE times where this caused a jeep to need to get winched up a hill instead of driving right up! Same reason i love my manual, i control the shifting, not a computer.
 

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Absolutely. Use 1st gear for all crawling, up or down... I find the benefits just as important when descending an obstacle.
 

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Yes, manual shifting when wheeling is a good thing. 1st gear in decent's helps the engine brake the Jeep.
 

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Discussion Starter · #8 ·
Yes, manual shifting when wheeling is a good thing. 1st gear in decent's helps the engine brake the Jeep.
I hear ya on descending in 1st... Of course.
I come down from the summits of high passes that have 4,600 ft of elevation change in just 7 miles!
If I rode my brakes down rather than engine braking, the brakes would last less than one day.

Thanks guys and gals.
 

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Some later model JK automatics (dont think 2008 had it?) also have a hill descent feature. In 4 lo on sufficient downhill grade, it will lock your speed based on gear (1st = 1 mph, etc). Sort of like a reverse cruise control. You can always override with brakes/gas just like cruise control. It uses transmission, engine, gears and brakes to control speed by computer more precisely than most drivers can. For folks not geared low enough to really crawl, this is a benefit. But it will only engage in 4lo, and only if the computer nanny senses the grade is steep enough.
 
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