Weird Noise from rear

[Micaoct]

Hello guys,
I have somewhat of an issue. Happened about 2 weeks ago, was driving on the freeway and there was a "clank" of sorts as I sped up to pass a truck, then a split second of hesitation then it was normal again except now I have an odd noise when I drive.

When I am driving, if I let go of gas and let it idle, it sounds almost like I have straight cut gearbox. If I put just a little gas, barely touch the throttle most of the noise dissapears, and if I put my foot down more there is a clank, clank, clank noise. It's not always the same, but I noticed it only appears when I am moving and it isn't related to engine speed, rather tire rotation.

I was wondering If i could get some input from the experts here. I think it might be my differential or driveshaft. I replaced the fluid in the diff a week ago but the noise is still there, and it seems to have gotten louder lately. Not sure if it's from inside or a bearing or whatnot.

Thanks for any input.

[slow_ti]

I was thinking it's your diff. But wait for Jess to come in and talk lol.


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[1996 318ti NY]

Your guibo could be shot/torn and slapping the side of the channel the trans/driveshaft sits in.

Best guess i could give. Jess might have a better answer though.

If the sounds is more mettalic (metal on Metal) probably not the guibo, But if it sounds like Rubber hitting something almost like a rubber mallet then its more then likely the guibo.


V/R
Paul.

[1996 318ti NY]

To add if it sounds like this its more than likely the guibo AKA the Flex Disc, EASY to check just have to jack the car up slide under and look where the black drive-shaft meets the Transmission ( silver) there is a rubber disc with 6 bolts in it, in between the drive-shaft and Transmission. If this looks ratty theres your cause.

http://www.youtube.com/watch?v=pGd5H...eature=related

V/R
Paul

[Micaoct]

Thank you for the suggestions so far, I am going to check the guibo in a bit, it doesn't really sound like that, I would say it is a little more metallic sounding and more consistent. The noise when I go to idle while driving throws me off though. It sounds like a legit Straight cut gear box just a little less high pitched.

No strong vibration or anything of that sort though.

[1996 328ti]

And if you change the guibo, replace the center load bearing at the same time.
But the sound shouldn't sound like it's from the rear.

Check the wind guards in front of the wheels.
Maybe they are vibrating?
I had one that sounded like a baseball card hitting spokes on a bicycle wheel.

[cooljess76]

Whatever it is, it sounds like it can be something very serious. I'd stop driving the car until you find out exactly what the problem is. If the noise is constant, try jacking up the rear wheels and turning the driveshaft by hand. Also give the whole drive line a good yank to see if anything is loose. Could be something simple like a shroud rubbing on the driveshaft or maybe an exhaust bracket snapped. Also check the brake shields, sometimes they'll rub on the rotors and give you a metallic scraping noise. If it is something like the center load bearing, you definitely want to find out before it's too late.

[familytruckster]

Check the wheel bearings too, pretty easy to do while in the air checking everything else.

[spidertri]

Check the diff output flanges and the CV joints on the axles. It's possible for the output flange to pop out of the diff, just push it back in. On the axles, look for torn boots or grease thrown everywhere. Grab the axle and try to rotate it, it shouldn't rotate at all without turning the diff and wheel too.

[Micaoct]

Thanks again for the suggestions everyone. I have been really busy so I haven't had much time to do anything to it or really get down under it. I've had some time recently and it appears that my differential is toast. I've been using my bike for transportation for the past week or so. RIP

Would this differential fit the Ti?

http://cgi.ebay.com/ebaymotors/ws/eB...#ht_1688wt_939

Looking at picking that up and getting it installed. At least it's warm now so I am not desperate for the car. Just need to confirm if that will fit before I buy it. Thanks again, you guys are the best!

[cooljess76]

Originally Posted by Micaoct

Thanks again for the suggestions everyone. I have been really busy so I haven't had much time to do anything to it or really get down under it. I've had some time recently and it appears that my differential is toast. I've been using my bike for transportation for the past week or so. RIP

Would this differential fit the Ti?

http://cgi.ebay.com/ebaymotors/ws/eB...#ht_1688wt_939

Looking at picking that up and getting it installed. At least it's warm now so I am not desperate for the car. Just need to confirm if that will fit before I buy it. Thanks again, you guys are the best!

http://www.318ti.org/forum/showpost....9&postcount=36

[Micaoct]

Thank you Jess, just noticed that is a sticky in the differential sub-forum. Boy do I feel like an idiot. Better keep looking then, d'oh. Hard to find BMW parts up here.

[bimbim]

wow rear diff huh? too late to check fluid level I suppose.