Can't identfy vibration

Slobin3d · Sep 15, 2011

mhjo said:
They called today and reported that they found some issues. I shall report the findings and results tomorrow when I get the car back. Thanks again for tips!

Does it sound like it is going to be fixed? If so woohoo! and hope it wasn't to spendy

mhjo · Sep 15, 2011

Well, I can at lest post a pic of the car (yellow one)

mhjo · Sep 16, 2011

Got the car back from drive shaft specialis. He changed the u-joint/yoke part that is attached to the driveshaft titself by cutting it off. The movement there was not good, as it was almost stuck. He checked shaft for imbalance, but found none. He also insuleted it with some carton stuff.

After test driving this evening I find it only worse. It now also vibrates/rumbles in OD at 60mph...

Also noise from pinion has got worse. Is the shaft too tight now (too long, pressing)?

Slobin3d · Sep 16, 2011

Sounds like your Shaft is seriously messed up. Did you get your $$ back for the "repair" since it is now worse? If you think the shaft is too long and binding I def. wouldn't drive it anymore as if you hit a bump and it can't compress it could break your trans output or pinion.

Your U joints should move freely with only the slightest hint of resistance, if not then either the needle bearings are bad or the cup has been crushed. I haven't messed with my drivelines on my mustang yet my exp. comes from my 4x4 wheeling background, but do your yokes have the bolt on U joint caps or is a C-clip type retainer?

mhjo · Sep 17, 2011

No, I haven't complained yet since I picked the car up friday (it's saturday here now). I will call him on monday.

Seems like thevibration has moved from one rpm to another really. When I delivered the car I had vibration only in 3d gear, now it's mostly in 4th (OD) at 60 mph.

I don't know what kind of u jionts, but I can check

GTA6t7 · Sep 18, 2011

Please keep us posted as you work through your vibration.

As I said in an earlier post, I am having same problem. I think I have two types of vibration. There is one vibration that comes on at 2200 RPM regardless of speed. This vibration is not constant it kind of cycles on and off every couple of seconds and is a fine vibration vs course (if that makes sense).

The second vibration comes on at 55 MPH regardless of RFP. This is a constant vibration and is course enugh to shake my mirror. I've has the drive shaft balances 3 times!

Thoughts?

Couped Up · Sep 18, 2011

Any possibility of running your car on a muffler style rack, with your rear axle elevated safely, or a wheel dyno? and don't forget about Tire balancing, etc.

mhjo · Sep 19, 2011

I rarely use the car thheese days because of the worst rainfall in 132 years.
I have today agrred to send the car back to my good mechanic and let him have the car for a week (while I go on a trip to Greece). He will be in contact with the company/guy that did the driveshaft job and work this out together.

I will report findings and results when I return from Greece October 3.

And again, thanks for ideas and thoughts to you all!!!!

Thwe vibration guide was great!!!

mhjo · Oct 12, 2011

GTA6t7 said:
I'm having the exact same problem with my 67 aod conversion. Your post said you had your axles balanced. I didn't know that was possible. Who did you take it to?

lost in translation. Driveshaft in my mother tongue is "middle-axle"

mhjo · Oct 12, 2011

Got the car back from the Drivshaft guys. Car was still vibrating. Returned driveshaft, they checked again. Still vibrating.

Now I have a deep earthquake rumble when deaccelerating downhill 40-50 mph. It's like 15-20 hz Cinema sub-woofer.

I really don't know what to do

GTA6t7 · Oct 15, 2011

I am having the same problem. I have an appointment with a speed shop next week to do the following:

1. Run the car on the dyno. If the vibration is still there, we know it's in the drivetrain
2. Balance drive shaft (again)
3. Put car on rack. If vibration still here do the following:
a. Take wheels off - try again
b. take drums off - try again
c. pull axles - try again
d. Pull driveshaft - try again

By removing the drive train one piece at a time I'll eventually find the problem. If it's in my new engine or AOD transmission I'm going to torch the car right then and there

mhjo · Oct 16, 2011

Good luck. Please post you findings. I will deliver my car as well to same procedures and post results.

Loup-garou · Oct 17, 2011

mhjo said:
Got the car back from the Drivshaft guys. Car was still vibrating. Returned driveshaft, they checked again. Still vibrating.

Now I have a deep earthquake rumble when deaccelerating downhill 40-50 mph. It's like 15-20 hz Cinema sub-woofer.

I really don't know what to do

Early in the thread, you mentioned the driveshaft being too long and being nearly "stuck", pinion noise and having the axle's pinion angle checked by the pros.

Vibration during deceleration is a symptom of incorrect pinion angle. What did the pros tell you about the angle of your AOD output shaft, vs. the angle of the pinion shaft?

Have you checked the transmission tailshaft bushing for damage from the "stuck" drivershaft?

Same thing with regard to the as the pinion noise; has the rear axle been disassembled and examined?

bikefreak600 · Oct 17, 2011

i had exact same problem before. simple fix. driveshaft is too short. not enough of the yoke slid into trans output shaft.
1.get your car in air at ride height (jackstands under rear axle tubes),
2. remove driveshaft, then measure distance between trans tail and rear diff yoke.
3. measure your driveshaft.

edit: i didnt see previous post saying driveshaft was too long ?

mhjo · Oct 19, 2011

Today the driveshaft was delivered to a different drive-shaft shop for check. Let's see what they find...

GTA6t7 · Oct 21, 2011

Don't mean to hijack this post but I am having the exact same problem.

Spent the entire day at a local race shop where they tried to help me with my vibration. Here's what we did.

1. Ran the car on a dyno. Vibration always present but at it's worst at 50MPH
2. Checked drive shaft length
3. Had drive shaft balanced and new U joints added for the third time - No change
4. Checked pinion angle - added 2* shims - no help
5. Installed different axles - no help

At this point we ran out of time. Mechanc thinks the problem is in the engine like the flex plate or balancer. I'm not sure and don't want to tear the car apart until I'm sure.

When driving the car home the vibration seemed worse.

I saw a post that said the AOD used a special yoke with a dampner to eliminate vibration. Is this true?

At wits end. Any thoughts??? Suggestions??

mhjo · Oct 23, 2011

You are welcome to join. I am still waiting for my driveshaft to return from testing..

mhjo · Nov 2, 2011

The second company that is checking my driveshaft called and said it was useless and behaving like "a horses head". They will replace the entire tube and shafts, so this will be an entirely new driveshaft.

I asked for written report that I can use for complaint against the other company that did the bad job. I guess this will solve my problem. Tomorrow I will test, and also bring car to a specialist in rims so they can also be checked and tuned too.

Slobin3d · Nov 2, 2011

Wow! So they built a crap shaft, then instead of fixing it when they had the chance and covering their butt, they said it's fine and must be something else? way to add gas to the fire

mhjo · Nov 2, 2011

What they also don't know is that my lawyer har a '67 convertible, and he regrds this as A VERY SERIOUS CASE

Can't identfy vibration

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