88 chev 4x4 won't engage into 4wheeldrive

When in two wheeldrive the driveshaft going too the front turns. When I put in 4wheel it doesn't move, so the tranfer case should be ok right? Is there
away to check the front axle, or something else I should check. There was no loud bang or again thing it just won't engage into 4wheeldrive. I looked over the wiring and everything looks ok. Any help would be greatly appreciated. Kev
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Unscrew the actuator on the front axle and have a friend turn the key on and put in it 4wd. If the actuator doesn't extend, replace it with a NEW one. Used ones are just waiting to leave you stranded...go with new! It is WELL worth the money!!!
If the actuator extends, then it should be in 4WD as long as the T-case is engaging!

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Before taking the actuator out, you can do this simple test. Put the transfer case into 4WD lo or hi with the key on. Leave it like this for a 30 seconds or so. Check the front drive shaft as you already talked about. It should be locked with the transfer case. Then switch the transfer case back into 2WD and check the front drive shaft again. If it is still locked, it must be locked with the front deferential. If it is not, the front deferential center axle disconnect must not be engaging.
The next step would be to put the transfer case back into 4WD and verify that you are getting 12 VDC to the front axle actuator. If you are not, then there is a problem with the transfer case switch or the wiring. If you do have 12 volts, then the actuator has likely lost the gas inside of it and longer is pushing the spline together.
My suggestions: If you do need to replace the actuator, get a vacuum operated one or a manual one. Then you will actually get 4WD instantaneously instead of having to wait for the gas to heat up. In MN in the winter, this can take some time.
"Shades" <shades_1970(at)netins(dot)net> wrote in message

was
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wrote:

get the 98up electromechanical actuator and harness. there is no vacuum system for a full size truck. the manual 4x4 posi-lok setup seems a bit african engineered to me. the 98up actuator works instantaneously.. I know, I've had one in my '88 K2500 for about 3 years now.
-Bret
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It was the switch in the tranfer case problem fixed thank for the help. Kev
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