Last night my front axle started popping and the 4wd light would go out and come back on when i let of the throttle. Then i can ease back in to it and it seems fine then the light will flash then start popping in and out again. the transfer case shifter is in 4wd and is not slipping out. could it be the acturator or something else?????

 

Is it actually coming out of 4x4 or is it just the light flashing . If it's only the light it could be a bad connection at the switch .

 

it is actually coming out and trying to go back in and grinding really bad.

 

Could be a vacuum issue. Put a vac gauge one the line to the actuator and put in 4wd while trucks running, see if it fluctuates. I belive the line on the passenger side should have vaccum when in 4wd, the drivers side when in 2wd. If no/fluctuating vacuum, repeat at the vac. switch, trace back the line to the switch and try it there too, the steel lines to the actuator have a tendency to rot. Then try near the pump if the main vac line to the switch on transfer case has none or fluctuating vacuum.

Could also be a stripped slide collar behind the actuator, or a bent fork on the actuator...try vac tests first.

 

Mine was doing this this morning on the way to work. When I first started out I could feel it coming out of 4WD then going back in. No grinding, but it was doing it. Then after a bit the light was going on and off, but I don't think it was coming out of 4WD.

I am pretty sure that mine has a dirty connector for the light, but wonder if it being cold could have any effect on the vacuum right at first? It takes about 5-10 seconds for the ABS light to go off on cold starts.

If yours is grinding when going back in I wonder if it's a t-case deal?

 

I've had the same problem with mine. I think I'm going to order a "Positive Axle Engagement System". I installed one on a friend's GMC several years ago and it works really well. Basically all there is to it is a cable to take the place of the vacuum system or in the case of the GMC the thermal switch. The advantages are that you know the axle coupler is engaged and you can put the transfer case in the low range without having the front axle engaged. - Steve

 

thanks for all replies, to add some more info the 4wd works fine in reverse but when i go forward it starts jumping in and out again the noise sounds like the front axle.( the axle u joint are fine) and if i put in 4wd and shut the truck off and let it sit a second or two then start it it works fine until i put it in 2wd and then go back to 4wd it does it all over again.

 

Mine would flash as well.Check above the skid plate for the transmission ,there are 2 vaccum lines there,One fell off and that was the prob.

 

It doesn't sound like a t-case issue to me. On my old 12v I put the posi lock cable in mine and loved it. I knew when it was in 4x4, and thats a great feeling! I was having a lot of issues with the 4x4 before I put the posi cable in and after I put it in I had no problems. That vaccum crap can do some weird stuff.