LS1 Engine Vibration - Worse With New Trans/Driveplate/TC

[M-1000]

02 WS6, 4l60e

The engine has always had a slight vibration 60-80km/hr, 1-2500 RPM. It was also audible in 3rd gear at 80km/hr - rhmm, rhmm, rhmm, repeat - sounding like it comes through the exhaust.

I put a new B&M trans, drive plate, and 2400 stall in yesterday and now the vibration has become much more apparent. Only under load (foot in to the throttle) through most of the rpm range, and now 50+ km/hr. Even in park/neutral bringing the RPM up the vibration is there.

I don't believe it was anything to do with the install yesterday, the driveplate sits on the hub on the crank (plate is concentric with the bell housing), the torque converter mated right up to the holes in the driveplate, the trans went right back in on the dowels, and I have crank endplay.

I'm thinking its an engine vibration as it has always been there but is now more apparent. Has anybody had an issue with a vibration in their LS1? My first idea is to try a new dampener. When the engine is idling the dampener doesn't turn true, it has a very slight wobble to it.

[jsmith564`]

same boat bro. my car is doing the same as yours. i have yet to figure out what is it. i'm getting closer i'm sure of it.

i have replaced motor mounts, done a tune up, checked about everything i could think of and it's still there. i have not replaced my trans mount, though i doubt it's that (could be wrong) i'm sure its in my engine.

i really hope you figure it out. cause we might have the same problem.

my car is a 2002 camaro ss auto. with 80,000miles all stock


check you're exhaust if you have headers and make sure they are not touching the floor of the car.

[M-1000]

i found your thread a couple of pages back. you hadnt reached a conclusion so i started my own thread.

after work tomorrow night ill unbolt the converter and see what happens. although i dont think that is the best idea as the driveplate is not a vibration dampener like a flywheel is.

i just went for a good pull on the highway with it, and it still has the same vibrations at higher speeds as it did before, but more apparent. its not a violent shake, but it still doesnt seem right.

i replaced my trans mount and torque arm bushing last year (they were both torn in half). that is when everything was still stock and it didnt help anything vibration wise. i got a good look at the motor mounts on the weekend and they are visually alright. no tears, cracks, etc. im very sure it is engine related.

my exhaust is stock. and that kind of relates to the problem. at higher speeds the vibration seems to be in sync with the sound of the exhaust from the headers to the ypipe. its kind of hard to explain. as i said above, rhmm, rhmm, rhmm, rhmm, repeat. almost as though its in sync with the power strokes. when i get above 160km/hr the whole car starts shaking violently, it doesnt seem safe. it did that before the trans swap though, just not quite as bad.

i need to do more research on the ls1 and how it is built. balance shafts, crank balance, etc.

[M-1000]

ill hook the scanner up on my way to work tomorrow as well and monitor the misfire info. i know misfires can give the same effect - stumbling/vibration under load. sometimes they can be minor enough not to throw a fault code but still be enough to make the car run poorly

[TransAmX2]

My first idea is to try a new dampener. When the engine is idling the dampener doesn't turn true, it has a very slight wobble to it.

I know it's common for the corvettes to have damper problems, I've heard of them needing replacement as low as 30kmi. I'd think if your damper isn't true at idle wheather or not it's "the" issue it's an issue you should resolve anyway, it will only get worse in my opinion.

[blue02Z]

as far as i know there is know balance shaft on the ls1. only on the 4.3 v6 and maybe the other v6's. also if you can see your balancer is wobbling just replace it. how many miles you have on it??


and another thing. when you bolted up the torque converter did you push it up to the flexplate with a prybar/screwdriver? dont ever pull up a tc with the bolts as it can cock sideways and cause a vibration

[M-1000]

as far as i know there is know balance shaft on the ls1. only on the 4.3 v6 and maybe the other v6's. also if you can see your balancer is wobbling just replace it. how many miles you have on it??


and another thing. when you bolted up the torque converter did you push it up to the flexplate with a prybar/screwdriver? dont ever pull up a tc with the bolts as it can cock sideways and cause a vibration

yes, i pushed the tc up to the plate before i bolted it up. snugged all 3 bolts and then torqued them down.

i took a good look at the balancer tonight and the rubber is pushed out on half and recessed on the other half. ill see how much gm wants for one tomorrow.

i had another guy at work rev it to 1300 for me so i could see what if anything under the car was vibrating. the driveplate and tc are fine, the engine and trans dont shake. the exhaust right after the y-pipe (right behind the clamp) shakes like a son of a bitch. right in tune with the vibration. the sound of the flow through the exhaust while sitting in the car matches the vibration. im 80%+ sure that there is an exhaust restriction between the outlet and the y-pipe. maybe in the muffler. there is very little flow out the pipes and it kicks out a burst of flow when i step in to the throttle or let off. when i hold it the flow cuts right back and the vibration comes in.

stock exhaust also, with the flattened pipe off the left bank

[cammed goat]

Try running the car with not exhaust and see if the vibrations go away. Could be a clogged cat or clogged muffler.

[jsmith564`]

i wouldn't think a clogged exhaust would cause a vibration, choke the motor sure, but i'm not an expert and these are just my thoughts.

i too see my exhaust shake while my car is running, but it's bolted to the engine and its going to move/vibrate with what ever the engine is doing. also the rubber ring around the dampener is about in the same shape as you're it sounds. i need to get a picture of it and post.

as i had said before, the car feels strong as hell, if it wasn't for this vibration i wouldn't know there was anything at all wrong. but the vibration has me worried it could do more damage if left unfixed.

[M-1000]

a plugged cat/muffler will definitely cause a vibration. it may be enough to still give power, but a slight/moderate restriction will mess things up with flow and back pressure that will cause a vibration.

we had a truck at work that had coveralls stuffed down the exhaust stacks from when it was towed in. the engine ran like shit (obviously from a full out restriction) but there was a definite vibration as the engine couldn't push out what it was putting out

[jsmith564`]

any update?

[cammed goat]

There is a writeup in this month's issue of GMHTP about, I think, the editors C6 having dampener issues. It had separated from the rubber. Just throwing this out there in case the same happens to other LSx cars.

[jsmith564`]

there is a similar issue with the pontiac g8 gt's in another lsx forum i read about. none of which describe the same symptoms that he or i are having that i can recall.

[jsmith564`]

There is a writeup in this month's issue of GMHTP about, I think, the editors C6 having dampener issues. It had separated from the rubber. Just throwing this out there in case the same happens to other LSx cars.

cant find it, have the link?

[cammed goat]

I went looking online and I found other posts regarding this very same issue. Apparently, there are many. There is something called a "cylinder balance performance test" that can help determine if it is ignition related, or internal.

[cammed goat]

Just tried to look online for that page in GMHTP about the wobbling Vette balancer. Can't find it. Apparently there is an issue with squealing/throwing belts. But wouldn't a wobbling/separated balancer cause a vibration as well. I would think so.

[jsmith564`]

i would agree. i doubt it's the root of my problem, but i do think i have a issue with the damper anyway which i'll add to the ever growing list. one day this car will be bullet proof haha

[cammed goat]

Just hope it's ignition related and not internal. But...if it is internal...time for an LS-6 upgrade.

[35th-ANV-SS]

Have you considered the idea of an out of balance tire or drive shaft? Those both are notorious for vibration issues.

[cammed goat]

Jsmith...go to the GM High Tech link at the top of this section. Ed found the Corvette story.