[NZAlfa75]

All

My driveshaft has developed a rattle at certain rev ranges, including idle. A loud harsh metallic sound. Ting ting ting...

Guibos are all good. Engine and gearbox mounts are new, but there is only 5mm between the aft engine mount and the driveshaft. Normal? I have a witness mark in the driveshaft (not fresh).

Lying under the car with the engine running I can pinpoint the noise to the front half of the driveshaft or centre bearing. I can move the centre bearing up and down about 10mm.

I don't want to have to pull thing thing out AGAIN, any guess whether it could be out of balance? Maybe time to start playing with hose clamps and weights?

 

[SamW]

Here are two guesses, and only guesses. One, try tightening the front pinch bolt, I had the same rattle on my Milano, I tried tightening the front pinch bolt, it would work for a while, then it would rattle again, I finally broke the 10.9 bolt and had to replace it. How I finally fixed the rattle is I replaced the entire drive shaft with a spare I rebuilt. The front guibo was the same, but what I did find is that the rear bearing that goes inside the rear guibo was pushed in and not in the rear guibo, so I took my time and made sure the rear bearing actually made it in the rear guibo, since then this new driveshaft has not rattled. I am not sure this was the cause, but it was not right and it is a very easy mistake to make. I think you really need to mount the rear guibo on the drive shaft before bolting it up to the clutch.

 

[AR4me]

I don't want to have to pull thing thing out AGAIN, any guess whether it could be out of balance? Maybe time to start playing with hose clamps and weights?

If the driveshaft is out of balance you _will_ feel the vibration. With the car in neutral and parked just sit in the driver's seat and free rev it.
Jes

 

[Craig]

G'Day Guys,

Sam, there's no pinch bolt on a TS but the rest is good advise.

Richard, clearance is listed as 7mm so you're probably ok, center bearing is mounted in a rubber diaphragm (how come Webster didn't change the spelling of that word?).

The handbrake cable and shift lever/linkage are both possible sources of your noise.

Give us a little history, have you just put this back together or has it been running fine for weeks?

 

[NZAlfa75]

When I did the big rebuild (and I've driven 9000kms since) I replaced the front Guibo and (I think) the rear. The centre is old but good condition. Things were lubed well.

I've only noticed the noise recently. You hear it at idle and then a couple of other places in the rev range, it comes and goes depending on rpm.

I've been meaning to check the handbrake cables for weeks. Then when I have the car jacked up I forget! I'll check but the sound appears to be further forward.

Gearshift is good, I rebuilt that too so it is tight (as tight as an Alfa gearchange can be ). Exhaust is also good. I feel no vibration while driving.

I really don't want to have to pull this driveshaft again. My exhaust is welded construction and I'm sick of cutting it!

 

[NZAlfa75]

Jacked it up again today and replaced the rear fuel hoses. Apart from the two 3" lengths of 12mm hose needed, sigh. Typical Alfa to have everything 8mm bore except two locations.

Anyway, Looking from underneath the handbrake cable is very secure. There is no vibration in the cable evident with the engine running. I'm sure the noise is coming from the centre oupling, but it is a rear rattle, like a nut bouncing round a housing. All nuts are tight and there is not a lot of movement in the shaft. The centre bearing seems well located in the housing. I think it is just there to annoy me

 

[SamW]

You are not a lone, Alfa gave a lot of us this little rattle, I have been chasing one for a while.... But do look at the bearing in the rear guibo next time you have a reason to take it apart.

 

[gzucca]

Milano Drive Shaft Rattle

I am having the same problem. I wonder if the drive shaft is hitting thes shift linkage housing. It sounds like a definite interference problem. Possible the cent er support has too much movement and the drive shaft is hitting something. Di you ever find the source of the noise on your car?

Glenn

Jacked it up again today and replaced the rear fuel hoses. Apart from the two 3" lengths of 12mm hose needed, sigh. Typical Alfa to have everything 8mm bore except two locations.

Anyway, Looking from underneath the handbrake cable is very secure. There is no vibration in the cable evident with the engine running. I'm sure the noise is coming from the centre oupling, but it is a rear rattle, like a nut bouncing round a housing. All nuts are tight and there is not a lot of movement in the shaft. The centre bearing seems well located in the housing. I think it is just there to annoy me

 

[BRUCE]

Try this - place a trolley jack underneath the (engine) bell-housing and gently raise it.

 

[alfaparticle]

I had a loud driveshaft related rattle on my GTV6. It most often occurred in first gear under moderate to hard acceleration. I was convinced that the driveshaft was hitting something but I could find no evidence. I did a motor swap and the rattle was still there. Finally it got so bad that I thought it must be in the clutch and that the time was ripe to install my rebuilt platinum transaxle. I found one transaxle mount bolt missing and the other one loose on the right side. I still don't know why it made so much noise and why it was almost always in first gear, but the loose mount was definitely the cause.

 

[86spider]

I had a rattle in the Alfetta, turned out to be item 24 came loose from being staked in place. Does the Milano have that piece?

 

[ToonRboy]

Probably not your issue, but my GTV6 had the cat replaced with a universal unit welded to the stock downpipes and merge section where the O2 sensor lived. Anyway, inspecting the thing I noticed that the center muffler donut hangers were stretched rearward some and came to the conclusion that the mod had moved the whole exhaust rearward about an inch.
The center can lip was making contact with the driveshaft giubo nuts due to insufficient clearance. a *ting*, *ting*, wait *ting*, ting* sort of sound. reversing the bolts so that the nuts faced the other way resolved it as a stop gap fix until I replace that front section with Euro pipes cut down to the proper length and everything hangs as it should.

 

[La Voce]

At idle speed, does the rattle stop or quiet considerably when you depress the clutch?

 

[gzucca]

Rattle

The sound does not change when I depress the clutch. On a side note if I push the bell house slightly to the passenger side the noise goes away. The noise is so loud it should be obvious but it is not. Tomorrow I will remove the heat shield and see if the drive shaft is hitting anything. I really think the center mount must be weak and the drive shaft is moving enough to hit something. Either that or I left a wrence somewhere in the drive shaft tunnel.

 

[D75]

At idle speed, does the rattle stop or quiet considerably when you depress the clutch?

Oh yes, mine does, despite the tailshaft guibos and center bearing being new & the exhaust clearance fixed and the gear linkage rattle tightened.

May I ask your experience here, LaVoce?
Clutch shaft bearings?

 

[gzucca]

I am thinking it is the pilot bushing between the drive shafts. I will disassemble it on Friday.

 

[evanwr]

I had a similar noise with my GTV6. It was the big nut holding the flange onto the clutch input shaft (what the back gibo bolts on to). The nut comes loose and allows the flange to move a little on the spline. The noise is a constant ting ting ting, most notable at idle and sounds like it could come from anywhere on the prop shaft. Easy fix, drop the back gibo, feel if you can wobble the flange with your hand - it won't be much movement, if so, undo nut, locktite and do up tight, about 70/75 ft/lbs. Regards Evan.

 

[D75]

Thanks Evan, sounds likely. I'll check that next time i have a chance.
The pilot bush is tight in mine.

 

[La Voce]

D75,
Evanwr is right on and describes exactly what solved my problem. The "spider yoke" retaining nut backs off just a tad and rattles, clacks, and clatters, until the clutch is depressed. A good re-torque with lock-tite solves the problem.

 

[D75]

Thanks everyone.