I've got a 1996 F150 that has recently developed an odd clunk from the right front. It's mainly only when I go to start it and it's either just before or just after it fires up, sometimes it doesn't do it at all. On some occasions I notice it if I hit bump but not near as often as during the start up. I've checked my motor mounts and my suspension and i can't see a problem anywhere. This also started happening after me and my friends went messing around. Any ideas? I've also replaced the starter thinking that was it (starter was in rought shape anyway), my brother was in the passenger seat and said he felt it in the floor, and once my truck has been started it won't do it agian for another hour or more usually.

 

Is your exhaust knocking againist something? Also check any bushing on suspension compontents as they may be allowing the part to shift under certain loads.

 

mines the got the same exactl problem only mines does it when i put it in reverse and back up tap the gas a little from a stop ill feel it..no idea what it is like u mentioned iv checked it all also. im stumped.

 

I have a bad radius arm bushing on the drivers side and it makes the clunk. This only happens when I am turning the steering wheel, most often when I am backing out of my driveway.

The easy way to tell if that is your problem is watch the radius arm while someone turns the wheels. You will see it move in the bracket if the bushing is your problem.

I do not know if this is your issue, if it only happens when you are starting your truck but it is a common clunking sound that comes from the front end.

 

As best as I could tell no my exhaust wasn't hitting anything and while on the driver's side the radius arm bushing seems to have shifted, again it's coming from the passenger side, which seems fine. Also I forgot to mention that I throught it may have been the starter and replaced it for a new one and my brother was sitting in the passenger seat and said he felt it in the floor.......

 

O and one more thing, once my truck has been started it won't do it for another hour or so usually.

 

Hmm that's weird.

Mine does it all the time now. When u put it in reverse. Taking off. Stopping. I'm wondering if my tranny mount is broke what ever it is it's like it's hittin my cab.

 

i would check motor and tranny mounts

 

those where my thoughts once i realized how often it did it. thank you

 

I think I found what it might be. It might be that one of the layers of substrate in one of my cats came loose. I crawled under it while someone else started it with my hand on the cat and I felt a bit of shake from it right when it clunked. I was also lookin right at it and it seemed to have come from straight in front of me. Either way I bought a higer flow cat a while back I haven't had time to install so that'll finally get done. Does this sound like a possible concept to anyone?

 

hhmm not sure but your right there so i bet your on to something

 

Hard to say without hearing it, but on my truck I had an issue with the back cat hitting the trans crossmember when one of the exhaust hangers broke. Put a new hanger in and it seems to have fixed it. I'd look at the radius arm bushings though, if they are dry-cracked and splitting (like most ive seen) they probably need replacing anyways, but the whole bushing kit is only like 20 or 30 bucks.

 

I think I know the clunk you're talking about. I've had (and currently have again) bad trailing arm bushings and its not that. I'm suspecting motor mounts. There are 3 clunks my truck makes currently, one is the trailing arm bushings, one is an axle pivot bushing that only clunks when the suspension gets flexed out hard, and one is the mysterious startup clunk. Mine too does it sporadically. I know my exhaust isn't the issue, just went through it and the clunk was there before and after. It seems almost like the engine is shifting on the mounts, I just mean the clunk sounds like a several hundred pound chunk of metal is dropping about 1/4". I had my motor out in August, shoulda replaced the mounts then!

 

I found the problem but for the record yes my radius arm bracket is bad. The bottom of it has rusted slightly were the bushing goes so the radius arm can move around and clunk. I think this is also why the alignment has been off since I've got it (lil over a year ago). But anyway the problem was an exhaust hanger my buddy welded on for me. The weld on one of them cracked and whenever I hit a bump it would shift to another spot, taking corners would sometimes would put it back in the spot it should've been, same with starting it. I've since rewelded it and no more clunk.