SS BadaSS

Pretty much as along as I've owned my 98 SS I've noticed this weird noise that seems to come from the front of the transmission. It only happens when I'm in third or fifth gear and I'm accelerating with the engine at a low RPM. Basically when I give it gas I hear this rattling noise that to me sounds like a failed or failing bearing. As the engine speed increases the sound dissapates until it's gone. I've had my transmission rebuilt once and when I mentioned it the guy kind of blew it off and just told me that T56's are noisy. I'm about to drop my tranny for a clutch install and I was wondering if anyone might be able to help me guess which bearing is making this noise so that I could replace it while the tranny is out. Thanks.

jd783

are you sure it wasnt spark knock

SladeX

I've got the same problem with mine, I just changed to a LS7 clutch with LS2 flywheel and new pilot bearing and slave (slave has new throwout bearing).

I still get that rattling sound, I'm leaning more towards a bit something internal to the transmission or perhaps it's just the engine running lean a bit giving a bit of popping in the heads, since the engine is so far under the dash, it just may be it...

SS BadaSS

Definitely not spark knock. I'm pretty sure it's a bearing that's loosened up and at low RPM and under high loads the roller elements are rattling. I'm just trying to see if anyone has experienced this and might know what bearing(s) are suspect.

Mike44138

iTrader: (3)

If you're sure it's from the front of the trans your choices would be pilot, throw out bearing, trans input shaft bearing, or bottom end bearings on the crank. A bearing on the crank or input bearing would be pretty obvious. You're saying it happens at low RPM in 3rd or 5th. You're not just lugging the engine possibly? Or maybe hearing clutch chatter? Have you tried running the engine without the pulls on to eliminate the possibility of a idler/tensioner/accessory pully? Does it happen with the clutch engaged and disengaged?

SS BadaSS

It's hard to explain, but if you guys heard it you would know it's a mechanical vibration. Whenever the engine is at around 1200-1500 rpm and I'm in low gear, 5th is where it is most prominent, and I floor it I hear a very mechanical rattle that sounds like I jar full of small nuts vibrating rapidly. After I get up to around 1700-1900 rpm the sound goes away. This only happens when the clutch is engaged and I'm loading the engine. If I accelerate gently the sound is almost non existent. So whatever it is it likes to resonate at those low RPMs and it increasing the torque load increases the rattling noise. Knowing this, I came to the conclusion that it sounds like a bearing where the roller elements have loosened up or something, but it could be something else that's loose that likes to vibrate. I'll probably just let it be since it has been doing it for so long without a problem. I'm replacing the pilot bearing with the new clutch. I replaced the TO bearing recently and it didn't change the sound.

99zmaro

iTrader: (4)

i hear the same noise so your not the only one

TransAminal

I get that noise once in a while in my transmission too. I also get a high pitched scream in 6th gear. I had a certified mechanic check it out, and he said basically the bearings are shot. I think its due to improper maintenance, the trans fluid was very clean when I got the car with 79K miles, I'm willing to bet that was the one and only time it had been changed

I changed the fluid after I got it with Mobil 1 ATF, and then added Lucas Trans Fix. I think it helped with the smoothness of the trans, but you can't fix bad bearings.

SladeX

it's definitly a bearing going, but where is something I can't figure out...

with the pilot and throwout bearing replaced, it's either internal to the engine or the transmission. Since both seem to be strong, I'm leaning towards the transmission more due to the nature of manual transmissions breaking parts first.

SS BadaSS

Thanks for the advice, I'll replace the pilot bearing if that doesn't fix it, there's always sound deadening.

Does anyone have the PN for the pilot bearing that I'll need?