99 Blazer 4X4 issues

[Howie21]

Hi, I have a 99 Blazer LT with 4x4 issues. When I first start the car up I am able to push 4hi and it will engauge with no problems, but after I drive down the road about a mile or above 15mph the 4 wheel drive will not respond at all. At that point I can pull over on the road and turn the car off and start it back up and BAM the 4 wheel drive will work again. At least untill I go about 100 feet or 15mph. Can someone please tell me you have had this issue and tell me how to fix it....

[MT-2500]

Originally Posted by Howie21

Hi, I have a 99 Blazer LT with 4x4 issues. When I first start the car up I am able to push 4hi and it will engauge with no problems, but after I drive down the road about a mile or above 15mph the 4 wheel drive will not respond at all. At that point I can pull over on the road and turn the car off and start it back up and BAM the 4 wheel drive will work again. At least untill I go about 100 feet or 15mph. Can someone please tell me you have had this issue and tell me how to fix it....

What transfer case?
Have you checked for codes?
Any 4W lights or blinking shift buttons or transfer case lights?
Any check engine lights?

[Howie21]

It has the 4 button selector with the auto option, I believe that is the 233. There is no 4x4 light on. No check engine light.

[MT-2500]

Originally Posted by Howie21

It has the 4 button selector with the auto option, I believe that is the 233. There is no 4x4 light on. No check engine light.

If it has the Auto4W button you have a 236 transfer case.
Did you not check the back of transfer case for transfer case ID?
Have you check fluid level.
Also that transfer case needs to be serviced with the GM blue transfer case fluid.

To get to the problem.
It needs to be put on a transmission/transfer case scanner to get codes and check out and test transfer case shifting.

If any codes post back codes.

Will 4W stay in in auto mode?

If transfer case is kicking out of gear on road or after a certain speed some of the speed sensors may be acting up.

Other things to check is the shift button panel for bad circuit board.
And all power feeds and wiring.

You will need a good repair manual with wiring and flow chart test.