00' blazer 4WD problems

Hello everyone, i have a 2000 blazer and im having some problems with my 4wd system. It has a 4.3l v6, and electronic 4WD (3 push button). I had a problem awhile ago with the transfercase solenoid not engaging, which i fixed, but then i started to hear a loud roaring noise coming from the front. (its not the tires i switched them with my GMC jimmy and it still made the noise) So i started to trouble shoot the problem. I checked the gear oil and changed it, then checked the CV outputs on the case. I noticed the drivers side one was kinda loose, i checked my jimmy and there wasnt near the ammount of play on it. I then noticed that the drive shaft was engaged, so i checked the vacum diaphram, and found that it was engaged. I unhooked the vacum hose and it disengaged again, but when i hooked it back up and started the engine it reengaged. On my jimmy it did not do this, it stayed disengaged until i went into 4WD.

So I need to a) replace the bearings? and b) figure out why there is too much vacum?

Im looking for some advice on how to go about this, as i want to have some experienced opinions before i go through the trouble of tearing the whole axle out.

thanks
-Verto

Looks like everyone missed you- sorry.
99up have an additional vac switch on the firewall that the dash switch activates so pull the vac line there to see if the front actuator releases then hook it back up and disconnect the electrical plug connector and see it that solves it (bad vac switch) or it could be the dash selector switch, the TCCM or computer for 4wd behind the pass kick panel. Are you getting a solid light and not flashing on the dash switch?

If the 2000's have the same vacuum swith on top of the transfer case as the older models, it is a well known VERY common problem for them to go bad. The part is about $15.00 and pretty easy to replace. It is on top of the transfer case towards the drivers side and has a bundle of three vacuum lines going to it, they just pull off. If you take it out and look at it, it has a ball on the bottom that should push in and spring back out. They stick in, causing the vacuum to be applied all the time.

my light is working and the transfercase itself engages with the button... so i guess its the vacum actuator on top of the transfercase :frown: it has about 80k miles on it and i rarley use the 4wd except in winter... so it prolly froze like 83T said... i had a look under there to try and get it out but its way at the top... was wondering if there is any secret to getting the thing out that doesnt involve ripping out the whole transfercase assembly?

thanks for the help :)

I can normally get them out without much of a problem. Put the vehicle up on a hoist or jack stands. There is enough room to get a wrench in there, if I remember right it's 7/8? I usually just use jacks stands and lay on my back so I can get my arms far enough up in there to get to it. Shouldn't have to remove anything else. When reconnecting the vacuum lines, there is a pin on one side that goes into a hole on the connector, all three lines come off and go on as one unit.

i can get under it without jackstands, but good to know i dont need to drop the whole transfercase...

i also have another problem, i think the bearings in the front diff have gone bad, where the CV shaft goes in the housing... is this a common problem? because i never has this on my jimmy... and do you know where i can get replacment bearings?

I've never had to get into a front dif, can't tell you anything about that.

woot problems are fixed :D thanks for the help got that vacum switch out and sure enough it was frozen... also fixed my humming noise by replacing my hubs and CV axles... i discovered my hubs were missing bearings and had some crushed bearings... and inner CV joints were missing bearings aswell...

thanks again for the advice :D