knocking noise under truck, need help!

Ok so it's been a while since the noise started, here's what I have done to my truck since:
4 new Monroe sensatrack shocks
reman rack and pinion
2 new cv axles
brake job (4 wheels)
new left upper control arm
2 new hub assemblies
2 new torsion bar adjusters
reman transfer case
removed front shaft (need to get a new or reman one)

Over 3k spent on repairs and noise just won't go away, am I missing something? dealer told me to change the torsion bar adjusters, which I had already done with no results at all,what is there left to do??? with all of that money I could just have bought another truck

When do you hear the knocking noise? Over bumps? Under acceleration, under braking?

most of the time

That's why I haven't been able to find the problem, but you can hear it during regular driving, don't need to do anything for it to happen, it just does and sometimes it will last thru the entire lenght of the trip, sometimes it will just do it randomly.

First shop I took the truck to told me it couln't be the CV axles as my truck didn't have any (not doing bussines with them as the don't seem to know that 4x4's DO have those) next shop I went to told me that CV axles were not the cause of the noise, but that I needed to replace them as one was already about to break, that's when we found out the upper arm was done, so I took it to a 4x4 shop, to a suspension and to a transmision shop and nobody knows the reasson
I really don't have any more money to spend on things that I might not need

Have you though it might be something silly like a piece of trim flapping in the breeze? Seems like you have really covered most of the major problem areas of 2nd gen explorers and then some.

Yes

First thing I thought was the spare tire, a co-worker had a similar noise and he found out that the spare tire was loose so I took it out, no luck, looked under the truck when they lifted the truck to install the shocks to see if something was loose and couldn't find anything that could be loose and swing during driving to make the noise so, I'm really frustrated

Have you checked the common things like lower ball joints and sway bar bushings and endlinks?
The sway bar bushings seem to be really common. Sometimes you can tighten the crap out of the endlinks and it will get rid of the noise, other times they need replaced. Often, they won't feel loose when you try to move them by hand.

What kind of sound is it? Does it sound like metal on metal... metal on plastic... random intervals?

Mine was clunking over bumps and driving me nuts. I changed the sway bar end links even though they looked good. They were shot when I got em off but I just couldn't see it while they were on the truck. Clunk is all gone. How's you universal joints on the rear drive shaft? Oh, rear drive shaft slip yoke might need to be lubricated as well.

What kind of noise are you talking about? Is it a rubbing sound, a clunk, a whinning sound what does it sound like? Did you ever think maybe the tires can be causing it. Rotate them. Just an idea. It seems you changed more things then probably needed to.

have you checked the transmission mount?

Provokr What kind of sound is it? Does it sound like metal on metal... metal on plastic... random intervals?
Sounds to me like metal on metal and it's almost as if someone was knocking at the door

Vinniety What kind of noise are you talking about? Is it a rubbing sound, a clunk, a whinning sound what does it sound like? Did you ever think maybe the tires can be causing it. Rotate them. Just an idea. It seems you changed more things then probably needed to.
I got new AT tires after the noise started(not because of the noise, I needed new tires), didn't do anything

jtsmith have you checked the transmission mount?
Transmission died at ~200K (yeah I know it's been on the road a lot) had a reman one installed in a pro shop so I would think that it was checked, don't know, just hoping

Joe & Brian don't know how to check those, I'll search here to see what I find about it

Thanks all of you for your replies, I'll keep you posted

Little update

So most of the time nobody rides in the back seat, today a fried of mine told me that she felt the knocking thru the floorpan but she felt it harder when I turned left, she was seating in the left side, so she switched to the right side and didn't feel it, so based on this new info, any ideas?

transfer case banging on truck because of the transmission mount being broke or loose
Don't assume they replaced it. Even if it was replaced it could be broken again, Stuff happens

update

Ok so I had an appointment cancelled today so I had nothing to do for a while and decided to check on the truck, took my haynes manual and went outside to check on the sway bar end links, the one on the drivers side was soo loose! I could have unscrewed it with my hand so I tightened it but the bushing is al torn up, I'll be heading to autozone tomorrow and buying a new set, I'll pick up the bushings for the sway bar as well, hopefully this will solve the problem, I'll let you know, as always thanks so much for your help

My 01 sport has been rattling for some quite sometime when i am always on idle or at a red light it rattles my explorer I dunno if I got loose ball joints or my flowmasters loose or what.

It sounds annoying after awhile cause when i am with my gf she keeps on telling me it sounds bad.

Haha tune to a radio station she likes and crank the volume

Sams01XplrSprt said:

My 01 sport has been rattling for some quite sometime when i am always on idle or at a red light it rattles my explorer I dunno if I got loose ball joints or my flowmasters loose or what.

Click to expand...

Follow your exhaust pipe all the way back. Make sure it's not touching anything. When you take the muffler (I see you have a new one) off, the rear pipe will spin because of the bend on the end. If you don't twist it back up before you clamp the new muffler on, it will rest against the shock! I left while my neighbor welded mine up and he didn't twist it! Wasn't fun grinding a full weld off, but it rattled just you say yours does. Also check all the heat shields along the pipe. They like to rust and rattle.

Update

Today I took off the front sway bar, noise is still there, I'll get new bushings as I already have it removed I might as well do it now along with the end links, so now we know this isn't the source, next thing to check will be the transmission mount, I have no idea how to check it as I went under the truck and didn't know what to look for, so I'll have it checked by a shop