Everytime I come to a stop at a light, i get this real deep rattle/vibration.

I first attributed it to the electric fan, but i couldn't seem to replicate it, even by unplugging the fan.......it still did it.

Then it, seemed to be more on the driver side, kinda right under the floor board. I had a feeling it had something to do with the header, maybe just a weird harmonic.

Well today, it seemed more pronounced. For ****s and giggles, I threw it in neutral and it stopped. Put it back in drive, and it started to do it again. It comes and goes.

So I repeated this over and over and when I threw it in neutral, it stops every time. Put it back in drive and it starts again. Has to be something in the power train. Is this symptoms of a convertor???

Watch, i always said i wouldn't put an aftermarket convertor in till mine puked, and now i decide not to race anymore.......the convertor will go!!!

Any ideas

 

Get under it and listen to cats, use big screw driver or something as a stethoscope. Most of the times the rattle is cats breaking up.

 

not the cats. If i put it in neutral, it stops

 

Yes, your right it's not the cats! I had mine cut off because the Dealer here told me that the shields were starting to fail and they needed to be replaced. They wanted $1200 to replace 2 cats and boy am I glad I didn't give it to them, because that wasn't the problem! When you guys find out what's going on keep me updated cause I still have that problem with no solution!


Thanks,
01_White_Light

 

Doesn't mean it is not the cats, either way, a little effort spent under the truck will help you pinpoint the problem.

 

i appreciate your help and response, but if something rattles in drive, and stops in neutral, and does it every time so it's not just 206 pure cooincidences.....it's not the cats. The cats are not mechanical by no means. Again, that's for the help.

 

Don, I've been having a similar issue which has gotten worse, it started only in reverse now when cold, I go into drive or reverse I get a squealing noise, into neutral nothing, once warm no problem's, shifts just fine. I need to finish paying off my blower upgrade and then I'm going to uprade the converter and buy a rebuild kit, I spoke to Greg E. he mentioned the converter or pump my be on there way out, I've also spoken to Matt/SVTF150, he ran an LPF rebuild kit/Art Carr and a Pro Torque converter into the deep 10's so thats the way I'm looking.

 

Tallimeca - Appreciate your courtesy response. I was not trying to be a a smart azz, but have been guilty on occasion; . I was at work earlier and did not have time to explain. I was trying to point out a potential flaw in logic; it could not be the exhaust since the noise occurs in drive, but not neutral.

Agree, it can be the converter or tranny, but it can also be the exhaust and that is easier to rule out if you pinpoint the source of the noise.

The motor's idle speed changes when you put the tranny in gear and the motor and attached exhaust are also now loaded. These changes can and generally do create more vibration/harmonics in the motor and anything attached to it such as drivetrain and exhaust. Thus if you have a bad cat, it can vibrate more in drive than in neutral.

Was I was trying to help you with is defining the problem. You do not have to spend a lot of time or be a master mechanic to get under truck and listen for source of noise. A little one on one diagnostics with truck can be as much or more helpful than us trying to offer up educated guesses of where the noise may be.

Sadly, if you take the truck to some shops and tell them you think you need a converter, you WILL leave with a new converter and tranny, even if they first find a loose, vibrating heat shield. Years back when I was an honest garage owner/operator, I had other shop owners brag to me about how they fleeced customers. Judging from the experience of neighbors and friends, a lot of shops still operate that way.

Hope this helps a little and that the problem is turns out to be something simple and cheap.

Later - Bob

 

This is the case with my truck, I have magnaflow highflow cats and the driver side only is rattling. When the trucks in neutral the rattling stops, throw it in drive and its back.

 

I would check your 02 sensors. Mine Had a rattle very similar to that and wouldnt do it sometimes. Turned out an 02sensor worked its way a lil loose and was vibrating against the Heat sheild. I took the cat down, Tightened the 02sensor as tight as I could, bent the heat sheild a lil more put it back and havent had the problem since.

 

i'm going to check check the o2 sensor and wiring. I never looked at that.

As far as the cats go.....i have brought the engine up and down in rpms to try to see what was going on. TRUST ME... I've tried to find anything that could be rattling, aside from never thinking maybe it's the 02 extender harnesses, even though i did wire tie them.

IF that isn't it, i'm thinking it has to be convertor related.

I even check the egr tube, i though maybe the nut came loose from the headers, no luck.

 

Tallimeca,
Have you taken a look at your exhaust system (other than the cats)? My first lightning ('99) had a deep rattle, similar to what you described. It would only rattle in drive, near idle... and generally moreso when there was more than 1 person in the truck.

I eventually found that the top of the muffler was too close to a screw head on the bottom of the cab; and it was bumping/rattling when the suspension loaded a bit. The solution in my case was to lower the exhaust system in that section. (used a pry bar, and tugged it a bit to increase clearance).


Scott

 

i checked everything. I'm gonna put it up on the lift in the shop, set the e-brake, put it in drive and see if i can pinpoint it.

 

Baffles have come loose in your muffler is my guess. Been there done that.

Good Luck!

D-Day

 

This is all so strange on my 99, I also also have deep rattle since I have had it for 3 year, but the noise is only in neutral, however following a rebulild of the tranny following a nuclear explosion in the box 18 months ago I pointed this noise out to the garage, who said it is not the tranny or convertor as these where replaced 'must be something else' -

Will go through the check list from you good folks to see if I can pinpoint it

Thanks..