Hey guys im brand new here, but hoping you guys can help...
My o4 blazer hs 4 wheel low and it engages the axles and gears but nothing in 4 wheel high. Any help

 

Are you sure that the front axle is locking in in 4LO? How have you tested it?

 

yes i have tested it. we have put it on the lift in 4 lo and they were engaged. the wheels had power to them. i have also had to use it to get through some mud that two wheel just wasnt getting me through. i think we found the problem yesterday evening. i just have to get it in hte air and make for sure they are engaging but it felt like they were when i drove it. the vacumn line going to the acuator was unplugged.

 

If the vacuum line to the actuator was unplugged, you wouldn't have had 4LO because that is how the front axle engages. You could have a vacuum leak causing the 4WD to disengage under load.

IMO if you have 4LO and 2HI, it is probably the encoder motor located on the case

 

I will check that. It appears to be working right now but i havent had a load on it. When you select four high you hear the click of it engaging adn i get power to the wheels. I thought it was the acuator but when i went to replace it i saw that the line was off. It could have came off while i was removing the accuator i guess. We traced the hoses while blowing air in them to see if i could hear or feel any leaks. When i put everything back together it seemed to be working. Before nothing happened when i hit the 4 hi button now it clicks and the light comes on. What is the best way to check the encoder motor or do you just replace it and go from there?

 

If you have 4Hi, it is not the encoder, unless it is going out slowly. Hopefully you have the problem solved

 

I hope it is fixed like i said i havent had under a load but the light hadnt came on before and now it is on and you can hear the click of ( what i think ) is the axles engaging. It has been a good truck and i dont use 4x4 much when i need it i need it. Hopefully its fixed and thank you guys for all the advice. I will let you know monday if it is truly engaging or not.

 

2000 blazer driving in 4wheel just fine.
When I needed it. Drove the cad some more
And needed it the light comes on but I can
See that the frunt tires are not moving
That the fxxk. I can hear it click in
Push the 4 wheel and check drive shaft
Locks in put it seems to have to much back
Lash in the drive shaft