I have a 2001 F-150 SuperCrew 4X4 with the 5.4L. In the last 2 weeks the engine or maybe the transmission has started making a knocking sound. The reason I am say maybe the transmission is that the sound only occurs when I first put it in gear. The following is the flow of how it occurs.

The engine starts and has the RPM's up to warm up. After about 10 sec. you put the truck into gear and soft knocking noise starts emitting and it get gradually louder until it is very noticeable. Now if you put the truck into Neutral or Park the noise stops. After that if you put it back into gear it doesn't occur agian. This only occurs after the truck is fully cooled down.

My question is has anybody else had this before? And about a month ago changed my oil to Mobil1 Synthetic 5W-30 instead of the 5W-20 that it called for. I have had several of this model and engine trucks and have never heard this before. Also I am using the Mobil1 Oil Filter so I don't think its my oil or filter.

Thanks

 

I have an 02 5.4L Supercrew and mine does exactly the same thing. I think it has done it from brand new. At 1st I thought it was a knock in the engine, but last month Ford put in a new engine due to cracked valve guides. Still does the same thing with the new engine. I also suspected the possibility of my exhaust (cat back magnaflow) as possibly being the cause. Or at least that is what the dealer will probebly tell me. I also have a superchip, but it does it with or without the chip, and did it before I got the Superchip. Keep us informed. Anyone else have this problem?

MJS

 

This morning it did it but not as loud. I listen under the truck and it sounds more like it was coming from the transmission but it was still hard to tell. MJS does your truck when you first shift into drive or reverse seem to jurk twice as if at first the transmission kicks in and then the rear axle. I know that doesn't happen that way, but that what it feel like.

Thanks