For the last few weeks my truck has felt like it was in 4wd when turning on pavement but it was not. Now when I use 4wd I hear a loud clunk coming from the front axle but 4wd does not engage. I put a new front actuator on a year ago. Planning to pull the front diff cover off wondering what to expect?

 

U joint maybe? Need a little more info

 

When I hear the clunk I can feel the 4wd engage only momentarily. When I turn on pavement witht in 2wd I can feel the front tires binding

 

my guess would be either diff. or hub but i really can't say for sure.

 

Probably a u-joint on the axle end...

 

I would pull the vacuum actuator, see if it broken and partially trying to engage the lock collar.

 

May be the infamous snap ring on the output shaft of the transfer case. When it breaks, it allows the output shaft to move in and out and thus engage the front drive when ever it wants to.

You do tend to see (feel) it happen when turning. Simple fix, just need to pop the rear output housing off and slide on a new snap ring.

Jeff

 

Thanks I have somewhere to start now. Will post findings when I get her checked out. Thank goodness it is not my daily driver

 

Finally got her pulled apart! Crunch time need it to go hunting in 2 weeks.
Pulled the cad unit off it does not work. Put new stainless vacuum lines from the cad to the transfer case. Still does not work. Should I be able to feel the vacuum with my finger? Heat setting will not change and I feel no vacuum with my finger off the vacuum pump.
Out of both driveshafts found three u joints starting to go.
Drained rear axle lube found milky oil. Removed axle shafts and crowm gear checked bearings all good.
In the front axle passenger side axle shaft moves by eye .020 at the cad unit. Isvthis normal? Is there a bearing there? I have a leak there at the u joint how hard is it to change seal? I can get to the part where the shaft is out easily, so from that point.
Checked the circlip in the transfer case all good there.

 

Yes you should be able to feel it, but since your heater control also doesn't move the door, it tells me that your Vacuum pump line is disconnected at the pump, the cowl, or the line is broken in between. Fix that and see where you are at.

 

I checked the only line coming off the vacuum pump I can see for vacuum but I feel nothing. New pump is $650. Hoping it has just stopped working from sitting to long. Going to get it back together and hope it works.
Ordered bearing bushing and seal for intermediate and axle shaft. Maybe that slop was causing the vibration?
Hope to have it back on the road tomorrow will see how it is from there

 

Movement of intermediate shaft was more like .060 once I used a prybar

 

for vacum pump try http://www.fixinrams.com/ you can fix for way way less than 650 or can buy a rebuilt one for 350ish (again could fix yours for even less than that). Pete Gould is easy going and knowledgable guy. He can fix you up with what you need.

Vacum at the cad should be - 2wd setting approx 10 inches and in 4wd between 10 and 20 inches. I just looked it up in the manual and checked mine the other day (manual is for an 01 but I think the setup is the same as yours). I cant remember which hose at the cad is which but there are two just check them both one will have vac the other not then shift transfer case and it will be the reverse of which hose has vac.

Also does your 4wd indicator light come on mine didnt which is why I was checking the vac and it turnd out to be the indicator light sensor was unplugged (duh from when I changed out my ac compressor two months ago).

On the u joints while you may have some bad ones in the drive line check the outer axle ujoints as well. I am in the process of changing mine now. Original ones got changed at 186k when I did the ball joints and now 106k later they are bad and making some noise so getting done again. If they are bad and depending on the condition you might change your ball joints at same time as all that stuff has to come off to do them anyway. Also great time to redo the axle seals as you have to pull the axles as well.

 

Balljoints were just changed. Tires turn fine while turned in both directions so u joints are fine at the axle. Passenger side front axle seal will definetly be changed since I got the intermediate shaft out. Rear axle is all back together now with new axle seals.
I have not put a gauge on the vacuum lines but I feel no vacuum so I am going to assume at this point that is the case. Will take it for a drive and see what happens

 

Anyone ever heard of a intermediate shaft bushing? Seams the dealer is trying to sell me a bushing instead of the original bearing. Going to the local driveline guy to see if he can source a bearing