sleddermb

Has anyone seen this. Engine runs great, but when I put it in reverse and press on the gas, the engine pings like the timing is out. If you have a load (trailer) and the engine has to work harder, the noise gets louder. I pretty sure it is the engine, but no idea what the noise is. 2004 f150 crew w/5.4.
Any thoughts??
Thanks Greg

xJimbos

Sounds like the reverse gear in your tranny is going bad. I don't see why the engine's timing would change from forward to reverse, unless it is your PCM doing something weird and changing the engine's timing when you throw the truck into reverse.
It may sound like the ping is coming from up front but this really sounds transmission related.

Or...when you put it in reverse somehow the front differential is engaging and the sound is some grinding of the gears. Do you have good operation of 4x4?

sleddermb

I don't think it's the tranny. It's never slipped or made noise. The only issue I had with the 4x4 was the vacuum module went a few months back (causing the front drive to partially engage), but the reverse noise has always been there since I bought the truck. The previous owner had the plugs changed and they had to pull heads off, but that shouldn't have anything to do with the noise I'm hearing. It's not really loud, but it's not normal (kind of sounds like a quiet diesel)