Tiago

iTrader: (27)

Im chasing down a vibration that comes and goes like a pulsating vibration at 1700 rpms or so. It will do this while stopped in park so it is not drivetrain related.

it is a 98 motor/tranny so I should ahve the strong flywheel but I suppose it could still be cracked.

I checked the converter bolts and they were tight, spun the converte and bolted it back up- didn't help.

I think the converter or the flywheel is messed up. Anyone else agree?


could there be anything internal in the transmission that could cause a vibration like this?

One thing I noticed while unbolting the converter was that the bolts had "slack" in the holes. That is, the bolt diamter was smaller then the flywheel holes so it could move out of center if you moved the flywheel with the bolts loose. I don't think this can make much difference since its still on center. The bolt holes were not stretched.

thanks,
_______

Yank

iTrader: (181)

Do you have poly engine mounts or a poly trans mount
that is a cause of most vibes

Tiago

iTrader: (27)

yes Poly trans mount....

but this vibration is characteristic of something rotating and out of balance. BTW the converter is a Yank 3000.

I had a poly mount in my LT1 car and didn't have this vibe.

jimmyblue

iTrader: (11)

I have poly motor mounts but did not have this
kind of thing until I changed converters. So it can
be an imbalance there but why it would appear at
some point in time, is the question.

Sometimes people rotate the converter 120, 240
on the plate and get better total balance. But the
"floating buzz" has not responded to that in my case.

Heavy as the converter is, it doesn't take much of a
mis-balance to make it noticeable.

TonyGXP

I had that problem in my TCI converter and took a **** a week later, btw it was only 2 weeks old when it happened.. Good luck.. change converters, either new Yank, or another Brand..

Tiago

iTrader: (27)

I Think the rotating mass finds a resonant frequency where it manifests itself. I can literally hear it buzz inside the car when its doing it.

Ive been driving the converter like this for about three weeks now. It runs fine, just an annoying little buzzzz....

rotating the converter didn't help in my case either.

thank,

Yank

iTrader: (181)

This is very common when any item is changed with the LS-1 alum engine with the revised firing order, even a exhaust change will effect the engine as can an aftermarket pulley
try to remove the belt an see
poly mounts transfer more that soft stock mounts and any movement will be enhanced.
even stock some have this type of vib in an unmodded car or truck stick or Manual

It looks as you have turbos installed they cause exhaust changes too.

I have unbalanced converters too see how much out of balance it would take to show up,
at low rpms and the amount is very high about the weight of 1 oz. and even then it is not that bad up to 3500 rpm
and Yank converters are balanced to under 2 grams and balance will not change with use

White_Ls1

Right after I installed my torque converter I had an annoying vibration/tin rattle noise at about 2500, I checked everything, basically narrowed it down to the slip fit heat shield on the passenger side. I have adjusted it a few times and the noise seems to get different with every adjustment. I can only hear it if I get things just right rpm(vibration point). I'm not worried I have over 1k miles since install and no probs.

Tiago

iTrader: (27)

thanks for the post, I will try a stock trannyy mount since its cheap and easy to test before I go pulling trannies and such

this is not on my turbo car, it is on my 94 ex v6 now ls1 car......

DrkPhx

iTrader: (15)

I believe this is the problem. I had the same thing happen to me. The reason you don't hear the knock when driving is because the converter shifts when put in gear and pushes the bolts against the flexplate holes. The constant motion keeps it there until the car comes back down to idle, which releases the load. The problem will only get worse because the bolt holes will stretch out from the constant shifting. You need to replace the flexplate.

I included a pic of my stock flexplate after removal.

Yank

iTrader: (181)

Yes, that will do it!!

Tiago

iTrader: (27)

Mine does not look like that at all, the bolts just aren't as big as the holes in the flywheel so there can be some movement until its tied down. The holes show no signs of stretching like you showed.


thanks,

frcefed98

iTrader: (16)

Stock tranny mount ran me 79 bucks at the local stealership, but it did get rid of my annoying vibration that the polymount induced.
GL finding it Tiago.
J

DrkPhx

iTrader: (15)

Mine didn't start like that. At first it was minor and gradually got worse. Hopefully that's not the case with yours, because you have to drop the tranny to replace the flexplate.

ondaroks

I have had the same problem. Just pulled trans. out to rebuild after i lost 3-4. Upon doing this i noticed a small crack through the tooth ring. after removing it i found another crack. Still waiting to get converter back and put all back together and see what happens. I replaced with a TCI flex plate.

SILVER 2288 SS

iTrader: (1)

i have a fti 3600 and my car just vibrates when the converter locks up then the converter unlocks what could cause this