And the grinding noise of the week is ...
 

Hi guys,

Well I was hoping to get a first opinion before I hear what my mechanic has to say about my latest problem. I sure hope I don't have to solve it like I solved the ticking noise with my last Camaro (see sig below) - traded it in for a Vette. No-one could figure out what was wrong with that one. Not on the boards, not me, not the dealership and not the performance shop.

So now I have a 2001 SS with 40K miles on it and NO mods (shameful I know). Everything had been peachy for about nine months since buying it and now I have the following problem:

It starts when the car warms up after about 30-40 minutes of driving (usually the more shifting I do the sooner it happens). Then I get this grinding noise when I get on it and give it some gas. It sounds exactly like when your in too low a gear for the speed your going.

It happens most in 3rd & 4th gear. Like when I'm in 4th at 2500 RPMs and I punch it then I get this really really loud grinding/rattling noise coming from under the forward centre console. Also the car doesn't seem to leap like it used to.

It also likes to do it in 1st. Like I am in danger of stalling unless I give it plenty of revs. If I do a normal start from 1st I get that same sound. You know, the sound like your revs are too low for the gear you are in.

Is this my clutch going bad or is it something wrong with my transmission?

TIA

boy hard to say what it may be.

i say pull the trans and see what...if any...signs there are of wear.

i'm thinking maybe a throwout bearing or possibly the gears in the trans.

you sure it's coming from the trans??

Thanks for the reply. I think that's where it's coming from. It could be the engine bay. It's hard to tell while driving. So if it is the throw out bearing how expensive are we talking? If it's the transmission I shudder to think how much it'll cost to rebuild.

Well I figured it out (I think*) It was good old fashion knocking. Just that I have never heard knocking before. Seems there should be a repository of weird engine noises somewhere. That would help.

Anyway, got the clue from another thread over the weekend and so I went from 87 octane to 93 octane and now she won't make that aweful sound no matter how hard I try. :)

*Disclaimer: I went from synthetic back to mineral oil around the same time so it may have been that had something to do with it too?

Any particular reason you were running 87 to begin with other than being cheaper? Not sure about the LS1, but the manual for the LT1 states 91 or higher.

Because like you said; it was cheaper. That and the fact that my manual said 87 minimum octane.