Heres the truck, 1997 f250 hd 351 w 4x4
Heres the problem, Under an engine load at about 2200 RPM's goin up a slight hill i hear what sounds like a rock or 2 bouncing around, its not constant all the time, ill hear it for a few seconds then it stops starts again. This only happens in drive, i rev it up in park or N and the truck sounds great. While driving around i hear the noise at 2200 i punch the gas, the engine down shifts and what now and i take off no problem i just lightly hear the noise once or twice thats it and then it goes back to to the 2200 rpm range under a load. Anything at all anyone can come up with would be greatly appreciated.

 

Could what you hear is pinging? Have you tried a higher grade of gas to see if that noise goes away?

 

Yes sry forgot to add that, i was running 87 mobil only 2 1/2 years, and then a buddy suggested running 91 and the noise isnt as bad but its still there. I also did the spark plugs as well and the old one had no unusuall wear on them. also the timming has NOT been checked since i got the truck not sure about before. Also i havent see the check engine light come on, and i do know that the light works.

 

Check the timing

 

I already have an appt with ford for wed morning cuz i want them to look at the entire truck i want to know what sounds bad or should be replaced or flushed cuz i got about 187,700 miles time for a check up by the pros. I told them bout the noise and ill add on the timming aswell, any other ideas ill let them know cuz i could care less about how much its gonna cost me i love my truck lol.

 

sure the "sound" is coming from the engine? could it be coming from the catalic converter or exhaust system?

 

Thats another problem i have, cant narrow it down cuz it only happens in drive, but i guess it almost sounds a bit echoed, so my first natural reaction was oh **** whats wrong with the engine.

 

i no mechanic, but without hearing it i think it is very possible the sound could be coming from your exhaust system. i don't have a 351, i have a 300. there are many smart people on this site and someone will chime it. i would think if it doesn't happen all the time its probably not the engine.

 

Well i thank you for your time and input and like i said any and all ideas i will look into.

 

My sons truck started making noises " like a half a can of marbles" in drive @ an idle. I got under it w/ a stethoscope and would have SWORN it was a main bearing. Then I noticed a loose bolt on the trans dust cover. It turned out to be loose flex plate / torque converter nuts.
Somebody had done some work (badly) before he got it.
Re-torque = no noise for 23K mi.

 

Alright i just got back from ford and the tech said he took it for a drive and couldnt hear anything, I had them check everything and everything engine and tranny wise is in perfect running condition except that they suggest a tranny flush and one of my ball joints is shot lol. The timming is perfect, no engine codes, no leaks, no cracks.

 

The noise could be either pinging or a small exhaust leak. At least thats what it sounds like to me.

Like what was just stated, loose bolts could be the culprit too. My friend has a 2001 F150 and it was constantly making this metallic vibrating sound at random times. I discovered that it was a heat shield for the exhaust had loose bolts.

Do NOT do a transmission flush. That will most likely do more bad than good.

Just remove the pan and drain the torque convertor if possible and replace the filter and refill the Dex/Merc fluid.