Rear of car Rumbles at Low rpm's

[x68monkeyx]

I just purchased an 87eta with 286k miles on it, rung great minus one problem. When im in 1st and second gear the rear of the car rumbles between 1.5-2.5 rpm's. Anyone have any ideas? Many thanks!

[SpecM]

csb? anyone care to second that?

[Adrian_Visser]

care to explain a little more? rumble is kinda a vague term is it doin it under load or only when u take your foot off the gas?

[x68monkeyx]

It does it when i apply gas, if i apply hardly any to get me moving it dosent do it, but when i apply more it rumbles

[SpecM]

I still say csb, center driveshaft bearing.

[x68monkeyx]

any way to test if thats the problem?

[DarkWing6]

i would lift the car up and look.

if you grab your driveshaft and move it around you will probably be able to know quick if the csb is really bad. if should have some give, but not a lot. it should feel pretty tight.


does the rumble change with speed? if you give it gas in neutral do you here this or only while moving?

[x68monkeyx]

no the rumble stays the same, but goes away after i get past 2-2.5 rpm. but im giong to check the shaft right now, thanks for the info

[drift]

Does it sound like wheel bearing? Or if your exhaust is somewhat loud, then it seems the noise covers that rumble over 2.5k rpm ?

[x68monkeyx]

wheel bearings were replaced not very long ago and the exhaust dosent seem loud at all

[Nicademus]

My exhaust was rusted through and hanging on mine plus there was a hole in my cat. It made similar sounds. Fixed both and now its a whole new car.

[Adrian_Visser]

+1 on the csb. symptoms are vibration/thumping/rumbling at lower rpms under heavy load right? i just did mine a week ago the shitty thing is it didn't completely fix the problem it just tightened up the vibration a lot but its still there. apparently (from reading other posts on here) the csb usually fails because the driveshaft u-joints are binding or seized so theres a good chance u should just get a whole rebuilt driveshaft to save yourself the trouble of doin it twice.

[x68monkeyx]

how much am i looking at to have that fixed?

[Adrian_Visser]

umm i dunno proly 3 hours shop labour. it took me five hours to do it but i had to pound off the old bearing from the ds. i think a refurb driveshaft should be about $500. i dunno whats the shop rate where ur goin to get it done?

[HST]

I'd just change your CSB and Guibo. If the noise is still there then look into the driveshaft. U-joints go bad far less than CSBs and Guibos.