so as some of you may have seen, i just finished installing my new magnaflow exhaust on the weekend, and it made the motor run so much cleaner and idles a ton better. now it seems it has introduced other issues.

the day i finished the install it started:

i can drive my truck for 10 mins with no hint of any problems, but as soon as everything gets warmed up and im driving there is an odd noise coming from what i think is the transmission from the interior of the truck. it sounds like slipping or sloshing of fluid or shuddering or something spinning against something dry, something of that nature.

if ive been driving it for 20 min or so, i can also hear the sound from the interior if im in neutral or park and rev it up, it comes at about 2200 rpm and gets louder from there.

now if i put it in neutral and poke my head under the truck and have someone rev it up, i cant hear anything except what i believe are normal noises.

also, if i put it in drive and hold the brake, then rev it up to like 1500 - 2000 rpm i can also hear the noise.

i took it into a great transmission shop that has worked on my familys vehicles for years, and he thinks its an exhaust leak and also said my exhaust is hitting my torsion bar crossmember. but i asked him to feel around all the seals to see where its coming from, and he claims that there is a small hole in one of my welds and its leaking from there and causing all this noise. anyway, he ended up just pulling the pan and changing the oil and filter, and he said he found small debris in the filter that looks like clutch, but not enough to be an issue yet.

first off, i had someone plug the exhaust with a welding glove on their hand when i got home to see if i could feel or hear where he said it was, and nothing. the exhaust is so tight you cant even hold it plugged for more than 2 seconds because the pressure gets so high.

even if it were an exhaust leak, this sound is in a completely different place that where he said the hole was. the hole is right under the pass door, and this sound comes from like beneath my dash/center console area and he told me my donut seals arent leaking on the exhaust manifold to ypipe. and this sound im hearing doesnt sound like steel exhaust hitting a crossmember.

im confused because it gets louder as the truck is driven longer, so it gets worse with heat, and i cant really hear anything from underneath the truck or in the engine bay. any help or input is appreciated because im out of ideas, its pissing me off and it really doesnt sound healthy. thanks in advance, hopefully i can get this figured out.

 

My first thought is your radiator fluid is too low, you have air in the system and the noise your hearing is the water/air running through the heater coil behind the dash.

 

damn that sounds like a pretty good idea, i never thought of that.

i just checked the fluid in the overflow tank this morning (cold) and it was a little low but there was fluid in there. i checked the fluid level right in the rad and it was high, it leaked out when i pulled the cap off.

i drove to my house (i was over at the gf's) and just topped it up with some fluid until it was at the hot line in the over flow tank. im on my way to work in about an hour so i will let you know if it helped my issue or not. thanks Hanr3.

 

well i took the truck for a half an hour drive on my way to work to try and cycle the fluid through and it didnt seem to help at all. still the same noise. thanks again Hanr3, any more ideas are appreciated.

 

Yes, one more. Typically the heater hose sits higher than the rest of the cooling system, any air in the system gets trapped in the dash area. You have to park with your truck facing uphill so the rad cap is the highest part, or install a flush kit in the top heater core hose under the hood. Start the engine and remove the cap on the flush kit until coolant comes out.

Search the forums for heater issues, dash water noises.