proper activation of pushbutton 4x4??

[stackz]

hey guys,

finally got the freeze plugs swapped out in my 91 4x4 that I bought recently so I'm checking things out on it.

It didn't come with the owners manuals so I wanted to be sure on the do's/don'ts of the push button 4x4 features.

When/how is the proper way to turn it on, when isn't, etc, etc.

Do you need to be in park? can you be crawling along in D or in 1 like on grand cherokees? dont run it on the highway? etc etc

There's variations in diff 4x4 systems and since I dont have the factory reading material I'm sort of in the dark.

 

[MrShorty]

Your 4WD system is a basic part time 4WD system with three positions: 2H, 4H, and 4L.

As with any simple part time system, only use 4H or 4L under low traction conditions (snow, mud, ice, sand, etc.)

By the book, you can shift from 2H to 4H on demand up to about 50 mph. I wouldn't recommend it unless you know the hubs are locked (IMO, one advantage of manual hubs over the stock auto hubs). That's quite a shock to the system when the t-case locks in and the hubs suddenly engage.

To shift from 4H to 4L you must:
1) have your foot on the brake.
2) be going slower than 3mph (at this point, if you have your foot on the brake, you'll be stopped before it shifts anyway).
3) transmission must be in N (P isn't good enough for the t-case shift module).

Any other questions (shift motor cleaning, auto hub replacement), try the search feature and see what you come up with.

 

[Charlie's_93EB]

to get out of 4H, unlock the hubs, and back up 10-15 feet.


in 4H or 4L, if you make a sharp turn, it will feel like you are running over your own tire, it normal.

 

[DeRocha]

By the book, you can shift from 2H to 4H on demand up to about 50 mph. I wouldn't recommend it unless you know the hubs are locked (IMO, one advantage of manual hubs over the stock auto hubs). That's quite a shock to the system when the t-case locks in and the hubs suddenly engage

The magnetic clutch within the T-Case will slowly bring the front shaft up to speed, but like MrShorty I wouldn't engage it with the hubs unlocked at over 35mph. Also when engaging 4x4 I always do so with Zero load (ie foot off the gas). This allows the system to shift into 4x4 with the least amount of jolt. Once or twice a month I will engage 4x4 (while its raining) to give front end components a little work out (no sharp turns). This helps keep everything lubed and ready to go. The electronic shift motor is notorious from freezing up due to lack of use. It really bites the big one when you need 4x4 and it fails to engage.