I have a 99 Silverado that I bought a few months ago. The 4WD would not engage, and I of course have to wait till the ground is covered with snow to figure out the problem. Well, the front axle will not engage in 4WD. When I push the button it sounds like it engages. When I have it on a lift the front driveshaft is turning, so I decided to buy the motor on the front axle assuming it wasnt working. I pulled the old motor out tonight, and it was moving back and forth. I did not put the new motor in as I assumed it would not fix the problem, and installed the old motor again. Does anyone know why it would not work?

 

Maybe the front diff is toast? Front diff carrier retainer failures are very common...

 

yep, mine failed the other way. I was getting ready to go up a gravel hill and pushed the 4wd button and BAM it locked the front up because the retainer went half way and jammed thus breaking and binding the setup.

 

Oh man, just what I didn't want to hear. Lol looks like I have a 2WD until after the holidays. I can't complain though, I got a good deal on the truck. Thanks for the help.

 

If its autotrac case its prob time for a rebuild...
The clutches in the case are prob worn out if thats the case you have..

 

might even be the transfercase motor mine took a **** last winter if it is that there not to bad to relpace i got a gm ac delco for around 250 shipped on ebay

 

If it's the xfer case motor i doubt the front driveline would spin.

I have a diff but I have to make sure my current one is good before I get rid of the spare. The clutches are burned up in my xfer case on the autotrac.

Prob cheaper tho to find one locally as it's prob heavy

 

Andrew is right, if the front spins but doesn't work once on ground, may be clutches. Drop the fluid and see what it looks like. Should be a nice smurf blue color.

I have TWO autotracs I'd be willing to sell...one is a local rebuilt with less than a 1000 miles the other is a remanufactured one with zero miles. I am just not sure how shipping would work. You can do the research on shipping and I'll take it (them) to where ever you tell me local (local to 20876) to drop off. Meaning shipping prepaid by you.

$300 for the 1000 mile one.
$450 for the 0 mile one.

Just shoot me a PM if interested.

 

I will take the cover off and see what's up with it. Thanks everyone.

 

Well if anyone was wondering I got it fixed. I actually didn't even know there wasn't a cover until I looked at it. I dropped it out, and could not get the actuator to engage the piece that connects the axle together. I took everything apart, found a bad bearing, replaced it, cleaned everything and installed it. It works now with no problems. I never even put the new motor in that engages the 4wd. I guess I just got lucky.