help finding clunk under dr seat!

[Four0Sport]

On new years day some friends and I did some wheelin in the snow, which quickly turned to mud, which meant I had to 'get on it' a little more than normal in some areas. I noticed towards the end of the ride I had a noticeable clunk when flexing hard or hitting big bumpes and dips. It sounds like its coming from under my dr seat, or right behind the dr seat. First thinkgs I check are the RA bushings. took off the bolt, took the bushinges off, no splits, holes in bracket are solid. front driveshaft u-joints are good, rear leaf springs are good, mounts are good, rear driveshaft u-joints seem fine. So I'm stumped...

My dr front ball joint does need replaced but I'm not getting the noise or feeling under the seat unless I'm cutting hard to the right and the rear of the truck flexes or I hit a bump or dip. Any idea what this could be? tranny mount? ball joint? idk..

I'm taking the truck on a benefit run this sunday, mild trails but still would like to get a look at something tomorrow and would like some pointers since i'll be working outside in 20 degree weather.

 

[zukman]

Welcome to the "Twilight Zone" you have picked up a nasty little gremlin that wields a hammer and waits for just the right moment to bang around.


Sorry couldn't resist as I have one too! lol

 

[Four0Sport]

lol.. its ok. it happened as i pulled kinda hard into the gas station earlier, so i quickly parked and crawled under the truck trying to see a rub spot or anything. found NOTHING. gonna try to get it on a rack and poke around.


i wonder what the people at Go-Mart thought when they saw me roll under my truck, i woulda laughed.

 

[jobjumper]

This sounds simular to mine. Stomp around on the step rail if you got them. Thats been my problem and you can duplicate this sound if it's loose. As far as checking in 20 degree weather, it's quick and will at least eliminate a loose step rail as a problem.

 

[mckenzieslayer]

Trans cross member?

 

[davidhicks16]

I had the same problem. all it was for me was the holes on my seat where they bolt to the floor had become egg shaped. My seat was not flopping enough to feel it but i could hear it. I put in new seats and my clunk went away.

 

[rhauf]

what year? if it's a TTB model check you're radius arm bushings. (if they were bad it would probably clunk on hard breaking in 2 wheel drive, on the street)

 

[Four0Sport]

First thinkgs I check are the RA bushings. took off the bolt, took the bushinges off, no splits, holes in bracket are solid.

seats bolted down fine.. I do need to check the trans mount. took it out today and didnt hear the noise as much, seemed to only hear it when working the front suspension, i know you can feel a bad ball joint in the cab but ive never had a ball joint feel like this. IDK, stumped still.

 

[black91EB]

sounds like a radius arm bushing to me, I have had a couple go, one on my ex and one on a f-150, as you describe, it sounds just like a thunk under the driver's seat. (or passenger's, if it's that side) James Duff has nice ones for around 20 bucks, so it's not all that expensive, but it can be a pain if your radius arm crossmember has never been taken out before, as it is riveted in on that side.

 

[Four0Sport]

yeah it sounds like radius arm bushings.. but like i said, i checked them and they were fine. its driving me insane! lol

 

[rhauf]

they only way to check them for sure is to replace them... my opinion anyway.

 

[Verno]

JACK, I'M GONNA GO OUT ON A LIMB HERE AND "ASSUME" THE R-A BUSHING IS GOOD ON DRIVERS SIDE....
OK couldn't resist. If bushing really does look good, then most likely you have something else loosened up that only gets stressed on hard right turns (ie. BALL JOINT) I'd say replace that then see if you're still getting the noise - could have just stressed the bad ball joint moe.
Vern

 

[Curtis]

they only way to check them for sure is to replace them... my opinion anyway.

I agree, a lot of times you wont be able to tell by looking at the bushing. My dads 91 had these replaced multiple times for the same clunking under the seat area.

 

[YBCold]

ima say it could be either, loose Catalytic converter heat shield, bad raduis arm bushing or some kind of exhaust leak maybe. or something along the frame rail is loose maybe the fuel filter? just rattling around down there.

 

[bats]

Ah, you beat me too it YBCold. I had a mysterious thump/rattle when I hit bumps or slammed my door. The catalytic converter heat shield got loose. I now use it to hold nuts and bolts.

 

[Four0Sport]

oh.. this isnt a 'thump' or 'rattle', its a 'BANG POP CLUNK'.

ran into some trouble tearing the front end down to replace the ball joints, abs sensors are rusted to the knuckle. blah!

 

[YBCold]

hm. im stumped for now.

 

[TedJ]

ran into some trouble tearing the front end down to replace the ball joints, abs sensors are rusted to the knuckle. blah!

I had the same problem, you don't have to remove them, just leave them in. In depth explanation in my how-to thread linked below...

 

[YellowSplash]

Jack, you might want to inspect the radius arm bracket, especially around the holes where the bushings rub. I had mine crack due to fatigue from the 6" lift and too much travel on the stock stubby radius arms. It would crack and make squeaking noises when i hit bumps, especially when turning. Double check the torque on the drop bracket bolts while your there too...

 

[Four0Sport]

Good idea Nick, i checked the OE bracket and the holes were still in good shape, i figured they were cracked and went ahead and picked up another bracket but it was in good shape. I do need to go around and recheck all the nuts and bolts holding the front lift on. hopefully i'll be taking it all off soon and putting it in the scrap pile. Ive got 2 D44s lined up to look at.