In 4HI mode you have permanent traction on both axes front and rear (50-50)
In 4LO mode, as in 4HI, but in addiction you've a shorter transmission ratio for your drive, it let you to climb steeper slopes ;-)
Depends on what exactly you have. If you have a push botton, you can just push the 4HI botton and you will be in 4-wheel drive in high gear. If you want 4LO you have to put the tranny in Nuetral and then push the 4LO button. On some models you have to be in 4HI before you can put it in 4LO. If you have a standard shift transfer, you have to put the tranny in Neutral before you can shift the transfer into 4HI or 4LO. If you have manual lock-outs on your front hubs, then you must put BOTH the tranny and transfer in Neutral, then lock in your front hubs, then put your transfer in 4HI or 4LO.
you can switch it anytime, but it is better if you stop and do it while in nuetral if it has a two setting 4x4 drive, i.e. 4Hi and 4Lo, then you can simply switch into 4hi whenever you want. you should only switch into 4lo when you are in neutral though.
vacuum modulater located under yhe battery box
Both 4hi and 4lo blink 6 times, stop and repeat? If you cant control the 4 hi-lo shifting the shift motor may need replacing. Easy 6 bolt (10 mm ) job. NO oil, no gaskets.
2hi | | 4lo | | | | 4hi------| if it is the same as a 1990 4x4
If you have a 2wd position on you shifter, then no. If it is a full time system with only 4hi and 4lo, then yes.
No, they are traditional 4 wheel drive with manual locking hubs and a 3 speed transfer case (2hi, 4hi, 4lo)
well first you need to determine if it's actually 4wd. if it is there are 2 things: there might be 4x4 buttons on the dash or you may have a stick shifter to do that. whatever the case, 4wd high is the best one to use. now, how to get there - if you have 3 buttons that say 2HI, 4HI, or 4LO then just press the 4HI or 4LO button, whatever you prefer. almost the same with the shifter, but with the shifter you need to stop the blazer completely and shift from 2wd to the 4wd gear of your choice.
The 4WD version of the Trailblazer has a rotary switch to the right of the steering wheel. The positions are 2hi, AWD, 4hi, 4lo. There is a N light for neutral. Rotate the switch clockwise from 2hi to AWD to let the computer select when to provide power to the front wheels. Rotate from AWD to 4HI to have 4 wheel drive. Remember to refer to the Owners manual for the maximum speed that you can travel in 4HI and 4Lo, and also how fast you can be going when you switch between modes. To go back, just rotate the switch counter clockwise.
4HI if you have to. 4LO should only be for very bad conditions where you could be stuck. If you can get by using only 2wd then do that. The least you use the 4WD the better, but it sure is very helpful when you need it.
The one with the 4hi, 4lo, 2hi and auto 4wd buttons takes GM auto-trak II transfer case fluid.
you could have a siezed front u joint replace it and the noise should go away.