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Scott in MN · Post by **Scott in MN** » Sun Jul 03, 2005 4:21 pm

I've been trying to track down a rattle that I have narrowed down to the front portion of my driveshaft. The rattle is pronounced during idle after warm up.

I replaced the front donut about 4 years ago and is still in good shape. Last year while trying to solve the rattle I replaced the center bearing. The new center bearing did not help.

I did some searches of the old forum and found a good one where psc and vincent concluded that it was the double nuts on the center bearing. I took the driveshaft back out today and rechecked the double nuts which, even though they seemed tight, I took them apart and retightened. Everything else seems tight.

What else can I check? I undid the pinch bolt and left the front spider in place, but the nuts and bolts in the front donut all seem tight. The pinch bolt was tight.

I don't know the long term history of the shaft. Should I find a shop to have it balanced. It's not perfectly smooth but it doesn't seem to vibrate too much as I rev the engine.

matt · Post by **matt** » Mon Aug 22, 2005 7:23 pm

Hi Scott have you found/solved the propshaft rattle. I'd be interested to hear because i'm in the same situation. i've recently o'hauled my clutch assembly to replace worn bearings and also had a propshaft rattle comming from around the centre section of the propshaft. I narrowed it down to something loose/broken in the centre muffler. But having now removed the centre muffler (something was loose in it) a rattle has come back intermitently.......I've checked all the donuts,bolts and the prop shaft isnt "sagging" at the cetre bearing + no vibration so i'm at a bit of a loss as to what it could be. If your centre bearing is shot would you also get some driveline vibration? before i write off another weekend working on the car it would be great to hear how you went.
Thanks Matt

Scott in MN · Post by **Scott in MN** » Tue Aug 23, 2005 6:33 am

I went ahead and took out my driveshaft (again). I was targeting the double nuts that hold the center spider on to the driveshaft. They appeared tight but I took them apart and retorqued them anyways. My center bearing was still fine. I did not find anything that would be obviously creating the knocking sound.

When I reinstalled the driveshaft, I did a thorough job of revving up the engine prior to final torquing of the bolts.

Once I got it back together it ran quiet. I can only point to assembling the center spider tightly and letting the driveshaft center itself before torquing. The quiet lasted about three weeks and now I get an occasional knocking spell again. Sounds like from the passenger footwell. Most of the time it runs quiet, but about once a week I'll have the knocking sound again. Who knows???

Even though I don't experience much vibration, my guess that the driveshaft is not balanced perfectly.

I could not find a local shop that was optimistic about balancing the shaft so I did not pursue that avenue.

Good luck and share what you find out.

MerrilGordon · Post by **MerrilGordon** » Tue Aug 23, 2005 10:36 am

I've had a knocking sound in the past and found it was usually the rear guibo nuts contacting the muffler. A few bashes with my favorite tuning device on the top rear of the muffler solved my problem. Maybe you guys are having the same situation.
Merril

Scott in MN · Post by **Scott in MN** » Tue Aug 23, 2005 11:49 am

Nope, I went through that in the past and solved it in a similar fashion. Mine is in the front.

It is something that Matt should consider though.

Post by **Michael** » Tue Aug 23, 2005 6:01 pm

Doesn't the driveshaft have a bushing on the front that slots into a recess in the flywheel?
Is this in good condition? I recall packing this with grease last time I had mine out. There is also a spring which keeps it properly orientated and some type of spring retainer.

matt · Post by **matt** » Tue Aug 23, 2005 11:40 pm

Driveshaft definately not hitting the exhaust, but the equivalent of the the front spring/case to locate driveshaft to engine michael mentioned in the centre section "join" between front and rear half shafts could be the problem? Even after packing with grease i guess there could be enough play to cause a rattle?
Ok this is what i could find:

Maybe rattle can come from (other than items already discussed) 35 or 37 if dry or really worn with grease? Problem is i don't think these parts are available anymore..... i could only get centre support bearing and as for the rest? what would you do, make sleeves to elimiate play?
Thanks Matt

Mats · Post by **Mats** » Wed Aug 24, 2005 3:04 am

I had a broken GB-mount that made the rear guibo rub against the body during "spirited acceleration". Easy to locate end remedy though.

Arn't there centering "bearings"/bushings in all three couplings? Plus the clutch cover bearings naturally.
I have a rattle in the driveshaft when I switch the engine off, never during any other situation then the final revolutions when switching the engine off. Have heard other 75t make the same noise but not any other transaxle cars, weird... :/

matt · Post by **matt** » Wed Aug 24, 2005 4:33 am

Heres the front mount with bush/spring retainer(whats the bush and spring retainer for? does the drive shaft move forward underload or something?)

Mats this rattle is metalic like a coin in a tin and fast(but intermittent), the sound i get when the idle is too low maybe 700rpm etc is different and seems to be more from the transaxle. Its wierd because i'm sure my drive shafts in good nic and other than centre bearing + double nuts i'm wondering what else can wear out and rattle in there.
That exploded view looks way more complicated than it is i bet when you've got the parts in your hands.
Maybe i could try and press some grease in there before pulling the drive shaft to see if it makes a difference, prob not really possible.
If scott s drive shaft has good centre bearing/double nuts, greased and torqued then noise gone for 3 weeks the rattle must be some wear in 35 or the spherical bearing and possibly stopped/dampened by newly packed grease??????????????

Mats · Post by **Mats** » Wed Aug 24, 2005 6:38 am

I have fixed a few "mysterious rattling sounds" by pulling the E-brake one notch...
The wire sometimes can make contact with the driveshaft and it makes a high-pitch tingleing sound.

I hope it's that easy.

matt · Post by **matt** » Wed Aug 24, 2005 1:34 pm

Thanks mats i must check this aswell

matt · Post by **matt** » Thu Sep 01, 2005 3:15 pm

Hi all well i removed the driveshaft and ended up rebuilding the whole thing, i intended to replace centre bearing anyway and check double lock nuts etc but those old guibos looked fine but where actually cracked when flexed so i changed them too. The rattle is gone for now. Having changed the lot i can only speculate what the rattle was, the spherical bearing and front bush/spring where 'dry' but it could have been the centre bearing too, so unfortunately i can't help on this one.

thanks for all the advice

Matt

Scott in MN · Post by **Scott in MN** » Fri Sep 02, 2005 4:26 am

Matt,
Good to hear your success, hopefully. Time will tell.

Scott in MN · Post by **Scott in MN** » Mon Sep 19, 2005 7:11 pm

Uhhg!!!

The rattle from the front of my driveshaft is back to rattling so much I wish something would drop off so I could figure what it is. After I put it together last time I thought I had it solved, but the rattle has come back gradually. I'll jack her up again and see if the front donut, spider or pinch bolt has come lose. But I'm getting frustrated.

I'm tempted to try another driveshaft. What is the compatibility between the different V6 transaxle Alfa's? My car is an '83. Can I substitute any GTV6 driveshaft? How about one from a Milano? What donuts should be used in such a transplant?

matt · Post by **matt** » Tue Sep 27, 2005 3:19 pm

Damn thats no good

, i hate these "land mine" drivesahfts, one spline out or guibo or balance and you're gone! I was a bit concerned about my clutch assembly when putting the drive shaft back in because the yoke (having replaced the support bearings) seemed to sit a few mm deeper into the clutch assembly so when i went to join the rear donut to yoke the donut did nt sit quite right/level/square, i drove the car like this for one day (without vibration)then my concern got the better of me and i went back and put an extra washer on the rear yoke/guibo bolts to get the guibo to sit right and its been fine so far but time will tell.......
I have got a rattle to deal with too, but its from the release bearing just touching the clutch forks i think at low idle, at first i thought i could put some extra washers(Farrk extra washers are solving all my car problems

) on the clutch slave cylinder bolts to allow a bit more travel when pressing the clutch pedal or maybe i could change the clutch slave cylinder "rod" with an adjustable length one? to get the travel spot on, theres a diagram in one of the alfa manuals for this somewhere. I think some cars have adjustable length slave cylinder rods, maybe i'll try one of these....
I'm not sure what you could do next Scott, thats a terrible situation to be in and will involve repeating steps to fix i guess.
Is it possible after market guibos aren't made to the same standard as alfa genuine one and therefore a possible source of vibration/rattle???????bit of a stretch i know....but where to from here?????
good luck
Matt

Front Driveshaft Rattle