2008 Jk issue
 

I have a 2008 jeep wrangler i have taken it off road and its troubleshooting. Its 6 speed when ever i try to crawl something in two wheel drive or 4 wheel drive hi, it dosent crawl it has no power it just shakes and turns off. 4wd lo works awesome. On the road car drives awsome only when off roading this happens. Anyone help me!!!

Sound like you need to hit the go peddle, gearing in high rang needs a little help.

I tried everything car just shakes like crazy and shuts off.

4HI is virtually useless when crawling in these things with stock gearing and it really isn't much better with deep gearing on the 3.8. Put that baby in 4LO and roll. :beer:

^^^^ what he said. I only use 4 hi on icy or snowy roads.

So my car is normal then i been told alot to not to use 4wd-lo unless really needed. I was going to take it to a mechanic to check it????? My jeep wasnt like this before i use to be able to do most of my offroading on 4wd-hi. I have change all my oils i change spark pluggs and cables. I dont know what else to check???

Who ever told you that has no idea what they are doing! If you going slow and crawling obstacles use 4lo. If your running high speed desert or moderate speed fire roads then 4hi or 2hi is fine as long as you are under control.

I don't think there is anything wrong with your jeep.

Northridge 4x4

This is stolen from a popular mechanics article "When do I engage 4wd?"
 

2H is used for normal road driving. Two wheels are driven, usually the rear, in high-range, the normal gear ratio used for everyday driving. Some vehicles may be constant 4WD or all-wheel drive, in which case they won't have the 2H option.
4H is used for normal-speed driving, but for when you need extra traction. These situations might include dirt roads, ice- or snow-covered roads, or hard-packed sand. Both front and rear wheels are engaged in high-range, using the same gear ratio as 2H for normal driving speeds. The front wheels aid in traction, making the vehicle more stable on loose surfaces.
4L is for when you need maximum traction and maximum power: sharp inclines and declines; heavily rutted tracks; deep mud and snow; soft, loamy sand; and extremely rocky surfaces. Both front and rear wheels are driven in low-range, which uses a lower gear ratio. The wheels turn much more slowly per revolution than they would in high-range, resulting in slower road speed but higher torque, which assists with traction and steep ascents. The lower gearing gives the vehicle better engine braking, making it easier to control on the descent.
If your 4WD vehicle has manual locking hubs, located in the center hub of the front two wheels, you'll have to engage them when you're using either 4H or 4L. These lock the hub and wheel to the front differential output shafts. Even with 4H or 4L engaged, the front axles won't drive unless the hub is in the lock position. Automatic locking hubs don't require this step, but you may have to reverse the vehicle after you disengage 4WD to unlock the hubs.

Alright thanks for the info!!!!