F350 - Loud banging from underneath

[Mark9405]

Guys,

New user that could use some help with a problem. Have searched the site as best I can and have not found anything similar.

2000 / F350 / 7.3 L turbo / 4WD / Auto – bought it new

There is a loud banging coming from under the truck mainly in the driver seat area (I think). Every once in a while it seems to be coming from the driver side front wheel also. It is intermittent and only happens when the truck is moving. At first when the banging started I could switch to 4WD High on the fly and that would quiet it but now the banging is not stopping even when I do that.

I rarely use the 4WD so I took it off road and ran it a little bit in 4WD high and 4WD Low – this did not help the situation.

I really don’t want to take the truck to my dealer – he once kept it for 30 days looking for a problem and charged me a fortune fixing things that were not broken. I did take it to my favorite mechanic who could not find anything wrong. He checked the u-joints and removed the drive shaft but the problem is still there and now getting progressively worse. He told me that he suspected a sensor was going bad and trying to tell the truck to engage the 4WD but could not verify his theory.

Has anybody got any ideas or heard of this before? Seems like kind of the opposite of a lot of other posts here – where the 4WD will not stay engaged.

Any / all help appreciated.

Thanks,

Mark

 

[JRJ04]

my guess is you have a sway bar, and the bushings have gone bad. More specifically...its probably the end links. Get under there and you'll see that right about under the driver's side floor board, there will be a long piece of steel attached to the frame on one end, and the other to the sway bar that is attached to the axle. Give that a good twist/shake...if you get any movement at all, the bushings need to be replaced. Pretty inexpensive fix.

Good luck!

 

[bigrigr]

Also check the shocks as well, if their leaking at all, they need to be replaced. Check them for tightness as well. Give the bolts a little "squeeze" with a wrench, top and bottom. The bushings tend to shrink over time and may need to be replaced. Don't forget the track bar while you're under there. It's the bar on the back side of the axle that attaches to the axle housing on one end, and the engine crossmember on the other. You never specified whether or not it made this noise when you were going over bumps, or if you were traveling on level ground. More detail might help us narrow it down. Good luck

 

[Mark9405]

Shocks look good. Track bar is a mystery to me- sorry not as proficient as I want to be. The noise/banging/now grinding starts up about 1 mile into the ride. It makes no difference: hard accel, smooth/slow excell 2WD/4WD straight/curve, smooth/bumpy - getting worsre by the day. Starting to sound like a grinding - putting her up until I can figure this out.

Thanks,

Mark

 

[Mark9405]

JRJ04,

Daggone - I took her up to my mechanic before I read this - will go up there in the morning and ask him to look per your advice. Got everybody in this end of town bumfuzzeled so far - maybe this is it.

Going on a hog hunt this weekend - wanted to take my truck instead of the wife's SUV - oh well.

Thanks,

Mark

 

[JRJ04]

does it get louder with speed?

 

[Mark9405]

Jourdan

No. Speed does not seem to have an effect. It is getting progessively worse - happens more often and sooner into the drive. Still very erratic with 2 or 3 different types of bangs/grinding/thumping noises.

Thanks,

Mark

 

[JRJ04]

Have you gotten under there and shook everything around to see if any of the end links or track bar is loose from worn bushings? lets get that eliminated first.

 

[Dogman]

Carrier bearing, U-joints, T-case, Flywheel problem all come to mind.

 

[uloadit]

Check the front of the spring near the bumper, some times the eye of the spring moves over from the rubber bushing and bangs the frame. Let me know how this works out,Should be sitting in the middle of the rubber bushing