The other day when driving in traffic I could hear a rattle that was coming from my truck that was bouncing off of the other cars. It only makes the noise in the 1.5k - 2k RPM range. My first thoughts were that it was an exhaust problem and possibly a bad CAT. When I got home I did some testing and found that the noise only occurs when the vehicle is gear. I had a friends crawl under and try to pin point it and he said it sounded like it was coming from the transmission pan or bell housing area.

We checked the fluid and it was nice and red but it was a little low. We put some more trans fluid in to bring it up to the correct level hoping this may be all that was needed. We begin to test again and it does sound better now with the correct amount of fluid but its still slightly present.

I have noticed that lately the vehicle doesn't want to shift until its in the higher RPM range when getting on it to pull into traffic and such. It also seems a little sluggish going up inclines. I recently changed the TPS thinking that it would help but doesn't seem to have made a difference. Anyone have any ideas what could be causing the noise?

 

Filter maybe loose, check the access plates also. Wouldnt hurt to check around outside for loose stuff also

 

Looks like my friend was wrong. Took it to the trans shop and they looked everything over. Told me that it was infact the CAT that what making the noise like i had thought.

 

Well thats good

 

Yup. Time to straight pipe it lol. I assume that the stock pipe is 2.5". I can get all the parts for about $12 and make money off the CAT at the scrap yard.

 

now,now. - I think you mean you are installing an aftermarket 'high-flow' catalytic converter. removing them entirely is illegal under federal regulations in both the US and Canada and moderators understandably take a dim view of persons announcing that they plan to or have broken the law.

Thus there are no straight pipes - ITS A HIGH FLOW CAT

actually real aftermarket high flow cats are fairly cheap, don't hurt performance, save lungs, AND keep you legal - it's what I'd do