98 Blazer 4x4 issue

[scrappy15728]

I just changed my transfer case motor for my 4x4 and
everything seemed to be working fine. It would shift 2hi to
4hi and back. Only problem is now is that my front drive
shaft is not disengaging from 4hi even though my button says
2hi. I cannot shift into 4lo and my 4hi SEEMS to be acting like my 4lo. I have no idea what to even do about this, not sure
how to search the problem online. All I know is that my
motor was bad, I put a used one in and works, just something
isn't working right.

I am just getting very irritated with this as it is just one problem after another. ANY ideas about what to do will be appreciated. Thank You!

[old_master]

Make sure all of the tires are the same size and equally inflated. Do not operate 4WD on dry pavement.

The vacuum actuator under the battery tray must receive and hold vacuum in 4WD HI & LO. When vacuum is applied to the actuator, it must pull the cable toward the actuator 1/2" to 3/4". It must release vacuum immediately, and the cable must be released, when shifting to 2WD.

If the vehicle is stopped and all wheels are on the ground, you will not be able to turn either driveshaft.
Anytime the vehicle is in motion the front driveshaft turns. In 2WD it is driven by the left front axle. In 4WD it is powered by the transfer case.

Post your results.

[scrappy15728]

i did see alot about the actuator so i think i will give that a try...is there any way of testing it or checking to see if its bad?? how would i go about checking it...thanks

[old_master]

You really need to remove the battery and the tray to get a good look at it. Pull the vacuum line off and stick a piece of vacuum line on actuator fitting. If you have a vacuum pump, apply 16" of vacuum to it and you should see the cable pull in. If you don't have a vacuum pump... suck on the line You won't be able to apply 16" of vacuum by sucking on it, but you should see the cable start to move, and the diaphragm must hold vacuum.