what could this be???

[nwcatman]

yesterday was doing about 65 and took foot off gas and at about 1500rpm i got a growl almost sounded like a had an exhaust brake. began playing with it and does same thing in neutral (let off on gas, shift to neutral) so leads me to believe is a drivetrain noise. but since is intermittant its hard to pinpoint. quits at lower speeds. any thoughts are appreciated. thanks

 

[CLAYTON]

Was it a quick growl?

Did you take your foot off the go pedal fast?

Where did it sound like the noise was coming from?

 

[nwcatman]

Was it a quick growl?

Did you take your foot off the go pedal fast?

Where did it sound like the noise was coming from?

wish i knew where it was coming from. doesn't seem like from the pumpkin though. yea i took the foot off the pedal fast, then as it started to decelerate, at about 1500 rpm, until about 800rpm, the noise was there. but it sounds different at different times and doesn't always do it. my son has a 99 3500 dually w/an exhaust brake and sounds like that only much quieter.

 

[bpenrod]

I've had my u=joints make weird noises while slowing down. Went underneath and they seemed tight but then went out about a month later.

 

[nwcatman]

coming home from work today and w/in about 3 minutes was doing 65 mph and then let off on gas and sounded real bad, but never did it again all the way home. but, is also making a slight growling noise under acceleration. driving home takes 30 minutes w/approx. 6 "let offs" and like i said only did it once. and engine is idling slightly rougher than before. sure i wish i knew whats up!!!