Engaging 4x4 in 84 High Sierra

[19gmc84]

Anybody know how to engage 4 wheel drive...I have a 84 GMC Sierra.

Lock hubs...
2wd drive to 4hi...I can transfer in Drive while shifting up once ?

4hi to 4lo ...I have to put in Nuetral and shift up one more time?

4lo to 4hi ...back in Nuetral...shift down once.

4hi to 2wd...in Drive...shift down once.

Then do I back up a few feet before unlocking hubs?

Just got truck and not really sure how I go from 2 to 4x4...plus do I shift straight up and down...or does it go up and to the side...or straight down to 4hi and then down and to the side for 4lo? Help!

 

[MrMarty51]

I do`nt know about side stepping the shifter. My 93 K1500 does`nt have a side step built into it, just straight back for HI 4X4.
I do know that if You have been running in 4-WD and when You try to shift from four to two wheel drive and if there is "ANY RESISTANCE" to the lever, then, try backing up about ten to fifteen feet, then try to shift the lever to two again.
It seems that when running in low range on solid surfaces is worse for binding the drive train than when running in high range.
Then unlock the hubs.
I have overhauled T-Cases that whoomever had been operating that unit, and running in 4X4 and there was a bind in the drive train that they must have had to use their foot and kick them T-Cases to neutral or wherever they were headed with the lever, strips the edges off of the gears real bad, amongst other things.

 

[MrMarty51]

You might also check on top of the sunvisor, if they are vinyl, GM used to print the instructions on the top sides of them.

 

[RetroC10Sport]

http://www.gmsquarebody.com/forum/showpost.php?p=144004&postcount=5

 

[19gmc84]

http://www.gmsquarebody.com/forum/showpost.php?p=144004&postcount=5

Thanks for the link !!!

 

[Stoichiometric]

I have been reading some of the posts here and people mention activating their 4x4 at low speeds. I was always taught to come to a complete stop, put the truck in N, and then shift into 4x4. Then inch ahead slowly until the T-case activates the vehicle treat.

Is it hard on the T-case to shift into 4x4 while the truck is in motion (ie. under load)? If not, what is the highest speed you can put it into 4x4? What about the push button 4x4, is the mode of action any different than the floor shifter?

 

[AuroraGirl]

I have been reading some of the posts here and people mention activating their 4x4 at low speeds. I was always taught to come to a complete stop, put the truck in N, and then shift into 4x4. Then inch ahead slowly until the T-case activates.

Is it hard on the T-case to shift into 4x4 while the truck is in motion (ie. under load)? If not, what is the highest speed you can put it into 4x4? What about the push button 4x4, is the mode of action any different than the floor shifter?

it depends on the t case, the year, the fluid probably, and also the selection.
my NP208 is shift on the fly up to.. oh **** its like 25 or maybe it was 40... Im gonna say 25 to be safe. if your hubs are locked and you are driving in 2hi and you are "25"mph or whatever it is, you can shift down into 4hi safely and I believe its because synchronized. But if you wanted to shift into 4lo you need to stop, period, no reasonably getting around that. then neutral in auto but manual you would just want to be clutching. then over, down past neutral, and then into 4lo. then of course carefully engage appropiate forward or rear gear but this isnt the case on all cases all years.

I dont think np205 cases were all able to do that, only later ones i believe.
the np203 can go between its settings except the Lock ones I think. i could be wrong.

I would say if you can be stopped, its not a bad idea no matter how you cut it.


no idea on pushbuttons I dont own space age tech

 

[Ellie Niner]

it depends on the t case, the year, the fluid probably, and also the selection.
my NP208 is shift on the fly up to.. oh **** its like 25 or maybe it was 40... Im gonna say 25 to be safe. if your hubs are locked and you are driving in 2hi and you are "25"mph or whatever it is, you can shift down into 4hi safely and I believe its because synchronized. But if you wanted to shift into 4lo you need to stop, period, no reasonably getting around that. then neutral in auto but manual you would just want to be clutching. then over, down past neutral, and then into 4lo. then of course carefully engage appropiate forward or rear gear but this isnt the case on all cases all years.

I dont think np205 cases were all able to do that, only later ones i believe.
the np203 can go between its settings except the Lock ones I think. i could be wrong.

I would say if you can be stopped, its not a bad idea no matter how you cut it.


no idea on pushbuttons I dont own space age tech

The 208 can be shifted into 4H at up to 25mph with automatic hubs, though mine is happier if I shift it at lower speeds (I usually shoot for about 5mph if possible, as it's sometimes easier when you're rolling slightly than stopped completely). Of course once your hubs are locked in, you can shift in and out at whatever speed, as long as you're not standing on the accelerator and spinning tires.

As far as the pushbutton stuff goes, it probably will only complete the shift if you're moving at whatever predetermined speed is stated in the owner's manual.