hi everyone, i have a 93 3.9 dakota that i have just finished rebuilding. it is making a noise that i am having a hard time identifying. it only happens in park, when the engine and transmission are cold. the noise fades away when the engine is shifted into gear or neutral. it sounds similar to a exhaust pipe hitting something, but i know the exhaust isnt hitting anything. upon removing the bellhousing inspection plate i found all of the torque converter bolts were tight, and the surface of the flexplate that the crankshaft sensor reads looks like its been put on a lathe and spun a bit. the metal is shiny and has grooves in it, so its hitting somthing. the damage is uniform across the entire surface. i have inspected the crank sensor and it shows no signs of damage. as stated when the engine and tranny are hot the noise wont happen. im completely lost with this, and was hoping someone might have an idea about it. thanks.

 

anyone?

 

when you rev it up in park does the noise increase, or change in any way.

 

it goes away at around 1200 rpm.

 

If you are certain that its tranny related, then disregard this, but mine did that same thing and it was something inside the catalytic convertor. When in gear, the torque up of the drive train quieted it, and when warm, or at certain rpm it stopped. Turned out it was the inlet tube, rusted loose from the body, but when warm it would swell slightly, and get tight.

Luckily, its emissions exempt, so no more cat. problem solved....Well, ONE problem solved.

 

I wish it could be something that simple, but my cats already gone. I'll check the rest of the exhaust system though.

 

Exhaust is fine, and now it's happening in neutral as well when the engine is cold. any ideas?

 

hello?