Hey everyone I'm back yet again with another problem with my 4x4. 2005 f150 4x4 with the 4.6. So now when I'm in 4x4 and I give it a moderate amount of gas at once there is a hellacious and violent clunk from the front end. Can also hear what sounds like a hissing noise when I'm in 2wd on the highway and there's load on the engine like if I'm going up a hill. The noise comes from the front sounds like drivers side. I recently replaced my IWE actuators on both sides with OEM ford parts and funny thing is all this started after I did the drivers side. I took it all apart today and everything appeared to be normal. I'm taking it back to the shop Friday but was hoping maybe someone else has experienced this

 

Get a hand vacuum pump, hook it up to the IWE, and pull vacuum, and see if it leaks. Those little brake bleeder setups have a hand vacuum pump if you don’t already have one.

 

think my issue Is deeper. Took to the shop this morning and there's a lot of play in the front driveshaft. I think my differential kicked the bucket

 

I hope not for your sake! I did a front diff on my dads truck when the seals went too long leaking and started grinding. It's an Explorer Sport Trac, and it wasn't super heavy. Thankfully ebay had a good used pull for a reasonable price.

 

i don't see any other reason the driveshaft would have that much play in it. Also when I made my original post I don't think it's understood how loud and violent that so called clunk was. I'm 38 yrs old and have seen a lot in my day and when it made that noise it genuinely scared me. I thought my wheel was about to fall off. Was the equivalent of someone smacking my front diff with a sledge hammer

 

Oh, I get that. I had a loose pinion nut destroy a rear diff on my old Chevy Blazer. Two teeth entirely sheared off, and the noise it made was horrendous!

 

Updating for anyone interested. So I went out this morning and just for ****s and giggles tried to use the 4x4. Went into 4hi just fine and moved back and forth with no clunk, I was moving very slow. Tried in 4low with the same results. Even climbed a hill in my yard that 2wd wouldn't allow you to climb, no clunk. The last time I tried to use 4x4 when I heard the loud clunk I was briskly accelerating from a dead stop, not quite stomping the gas but pretty close. I'm starting to think about my cv axles, u joints and slip yoke now....if I find out anything definite I will update again

 

I've learned never to put my truck in 4wd at a dead stop because it makes a horrendous clunking noise when the IWE's finally mesh with the hubs. I always do it while rolling and wait a few seconds before trying to accelerate.

 

when I'm at a dead stop and put it in 4hi it's absolutely silent. Now when I switch to neutral and go to 4low there's a slight clunk, not bad at all. The sound I was describing in my original issue only happened after I actively pushed the gas pedal from a dead stop after being in 4wd and to add to that I pushed the gas very hard, almost stomping it

 

I must have misunderstood your post then. Maybe don't stomp on it anymore in 4wd lol.