Fin[UK]

Hi Guys,

Hope you can shed some light on this problem.

Car - Its a 96 GT 4.6 with Auto Trans. With 23K miles on the clock

Ok the problem, It started to have a Vibration noisewhen driving at over 50mph, on and off the power,

We checked the diff, and it was silent, We rebalanced the rear wheels and that made no difference.

The Auto box extention housing seal started to leak trans fluid.

On Axle stands running the car in drive you can see there is a noticable rotational vibration.

So what have I done so far to try and stop the problem.
[ul][*]Balanced the rear wheels (currently using the stock alloys for winter)[*]Fitted a ford Racing Alloy Drive Shaft, using the original yoke[*]Fitted new seal in the extention housing of the auto box as the old one started to leak quite bad)[/ul]
Now the Vibration is noticable at over 70mph so the problem has been lessened but its still there.

Any ideas so far......???

Right this is what Im thinking, I had to use the original Yoke on the auto box.(as the shafts only come with a manual box yoke)This Yoke has a Harmonic dampener style rubber and steel ring on it (1" wide and 5" dia), Could it be this ring thats causing the problem? Ive looked on the internet to see a picture of the same yoke but I just have not found one with this steel ring????? Can I remove this ring from the Yoke???? The idea of the alloy shaft is to reduce rotational mass..... And this thing is heavy

I have also got a new extention Housing with bushing and seal, didnt fit it as I need to get the car on a ramp to do this proper.

WHat do you guys think? Any help input would be great.

Cheers
Fin -From the other side of the Pond

96 Mustang GT
93 GMC Typhoon
96 Jeep Grand Cherokee
05 Seat Leon Cupra R - Shopping trolly

Fin[UK]

just keeping this on the front page

droptoppony

did you balance the front wheels also? I had slightly bent my 2 front wheels and didn't even know it and was having a shake all over my car. When i swapped on my new wheels my 70mph+ shudder was gone.

Fin[UK]

It does it with both sets of wheels Im affraid The New set is fully balanced, the original setI havefitted nowIve just re- balanced the rears to make sure.

Its this Harmonic balancer style devide thats monded onto the transmission endyoke that puzzels me?

As said we have sat the car on axle stands and run her up to 60 mph (with the old drive shaft) and you could see the car start to shake)

Fin[UK]

Not really a shudder, You can feel a vibration (not from the steering wheel) from the gear selector, But you hear a deep drone / humm that gets louder the more you go over 70mph

djb1187

aftermarket exhaust?

SmallFeesh

When you installed the new drive shaft did you also replace the Universal Joint (U-Joint)? That is usually the cause for such vibration! It could mabey possibly be a motor mount... but that dosent seem right to me... id bet alot it is your U-Joint!

Fin[UK]

Thanks for the reply guys,

Nope the exhaust is stock (I think) has all the Cats, Not knocking or anything like that


TheUJs on the Old shaft were fine, free with no play, The Alloy shaft had new ones fitted.

SmallFeesh

DANG! I coulda SWORE that was the problem! How about motor or tranny mount??? That is the only otherthing I can thing of that would make it shudder like that being up in the air, it cant be suspension....

Fin[UK]

Ive not checked the motor mount, the engine bay is like new and there are no knocks or clunks you normaly get with the mounts going bad......

Maybesomething caused the yoke seal to fail (Unless its a common thing), I know the problem is far less with the new drive shaft. But if the old drive shaft had worn the bush down...maybee thats the problem

Ihave the new extention housing with new bushing and seal ready to fit, If drive shaft was out of balance and the seal fails Iguessed that the Brass bush had worn in the extention housing.


But this brings me back to this balancer thingon the Transmission Yoke. Do you guys with stock drive shafts have these things?

Im into my American Cars (yep as Im in the UK, I can drive a good kind of Import...lol) and have never seen another drive/prop shaft with a harmonic dampening wheel on it, (but this is my first American Ford, Others have been GM cars


Question is Can I remove it from the yoke? Will this **** things up even more?