Bad a833 vibration with rebuilt tranny

[73Runner4spd]

Hey guys had a pretty mph related vibration in my 73 bird. So I took the cheap route first and balanced my tires and driveshaft. Still had the vibration. Pulled the tranny to have it rebuilt, was leaking out of the front and rear seals anyways. Plus I had quite a bit of play in the yoke. Replaced the 1,2 shift fork, and used the bearing/seal kit from passon. Got it all situated and took it for a ride. Still have a bad vibration in 4th gear around 60 to 70 mph. I can feel the shudder in the clutch pedal slightly (was a lot worse before) but it is still terrible in my shifter, and the rest of the drivetrain. I replaced the clutch two years ago with a neutral balanced flywheel (forged crank 400) and I rebuilt the 8 3/4, last year. Motor mounts and tranny mounts are in good shape. It does it between 60 and 70 in gear, neutral and with the clutch in. Will smooth out after certain speed. I was really hoping it was the brass bushing or tailshaft bearing as they were both in poor shape... any insight would be appreciated.

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Ohhh it also has a vibration if I slalom left at around 50 mph and up. I'm not sure if its related or not.

 

[Meep-Meep]

Did you check driveline angles? Get a magnetic protractor and use the U joint caps as a reference to take measurements from. You want them equal (but opposite) at 2-3 degrees. Assuming all that is well then I'd check how much up and down play you have in the slip yoke. Even installing a new bushing does not make the fit better.

 

[73Runner4spd]

Okay I'll have to find one and learn how to measure it. Any chance I have a warped axle? Or a bad axle bearing. Should have new carrier bearings when I had the rear end done...do they make larger slip yokes? If its a factory yoke and bushing where would the fault lie? Thank you!

 

[turbo36]

When you had the rear Diff rebuilt did they install a new yoke? It is not uncommon to get one that is machined off center.

 

[73Runner4spd]

When you had the rear Diff rebuilt did they install a new yoke? It is not uncommon to get one that is machined off center.

Not sure to be honest, I highly doubt it. You mean they come off center from the factory sometimes? This thing is irritating as hell.

 

[Hemi Rebel]

What you need is a sirometer. It can be placed on the dash or wherever you feel the vibration the most. With it you can determine the rpm and frequency of the vibration. With this information you will be able to determine where the source of the vibration is coming from.
At the speeds you are talking about I feel its a wheel/tire issue. You had them balanced, but did you have a road force balance?

 

[Dave L]

My guess is the pilot bearing if it does it with the clutch in

 

[turbo36]

Yes, I had a brand new one that was machined off center, when I went to return it we checked all the ones in stock and everyone was bad.

 

[moparmarks]

When did this start or has it always been there since you got the cars? Sense it does it with the clutch dis-engaged sounds like a clutch or motor issue.

 

[73Runner4spd]

Is not sure when it had started but, if I was motor or utxh related. Wouldn't it do it sitting there when I rev it up? Also why would it happen in neutral going down the road? Thank you.

 

[dvw]

I've been chasing the same type of issue in my E-body. Still vibrates over 55 even with clutch depressed or in neutral. Defiantly drive shaft speed. What I've checked. Aligned bell housing laterally and 90 degrees to the crank with-in .005". Drive shaft angles mirror each other at 1.5 degrees. 2 different drive shafts, balanced at dyno tech. Drive shaft runout less than .030". 2 different rear carrier assys, neither shake in another car. 2 different sets of axle shafts. Balanced rear drums. New engine and trans mounts. Only part I haven't swapped is the trans. It shifts better than any 833 I have ever owned and makes no noise. No vibration at all below 50 mph. Bad enough it loosens the shifter bolts in the trans. good luck
Doug

 

[73Runner4spd]

Sounds like we are in the same boat Doug. Rebuilding the tranny didn't help in my case ha. This is weird.

 

[texas69bee]

If it happens in neutral you have just eliminated the possibility of the tranny. Start looking at everything after that. Check to see if your axle is bent. Are you getting weird tire wear in the back? Could it be as simple as your tires weren't balanced properly. You said it happens at increased speeds and an unbalanced tire would make sense.

 

[mopar 3 B]

Have you tried tires and wheels on another vehicle or if possible have tires and wheels spun balanced on vehicle. Is vibration worse on excell, decell or no load? Does it disappear with engine shut off? Have engine to bell housing bolts been checked? Shocks OK? Have learnt just because things have been rebuilt does not mean they were assembled correctly or that new parts were any good. Check and recheck. A little floor Dino time tie it down and see what shakes!

 

[nitrojunkie]

Had the same type vibration in my t-bucket. Above 60 mph. Fought it for years then finally found out that the rear tires were out of round. Put on a set of Hoosiers and that fixed it. Just a thought. Bill

 

[dvw]

If it happens in neutral you have just eliminated the possibility of the tranny. Start looking at everything after that. Check to see if your axle is bent. Are you getting weird tire wear in the back? Could it be as simple as your tires weren't balanced properly. You said it happens at increased speeds and an unbalanced tire would make sense.

Not so, The output shaft is still spinning.
Doug

 

[texas69bee]

DVW
You are correct. The output shaft is still spinning but only from the car already being in motion. I reread your post. Have you found the problem yet? Do you have a 400 crank as well?

 

[dvw]

No, car is in storage for the winter. My engine is a 360. How ever it still vibrates in neutral or with clutch in, it's not the engine.
Doug

 

[Outlawd]

I've been chasing the same type of issue in my E-body. Still vibrates over 55 even with clutch depressed or in neutral. Defiantly drive shaft speed. What I've checked. Aligned bell housing laterally and 90 degrees to the crank with-in .005". Drive shaft angles mirror each other at 1.5 degrees. 2 different drive shafts, balanced at dyno tech. Drive shaft runout less than .030". 2 different rear carrier assys, neither shake in another car. 2 different sets of axle shafts. Balanced rear drums. New engine and trans mounts. Only part I haven't swapped is the trans. It shifts better than any 833 I have ever owned and makes no noise. No vibration at all below 50 mph. Bad enough it loosens the shifter bolts in the trans. good luck
Doug

Just curious...did you ever find the problem. got a buddy with very close to same issue.

 

[Chi Town Runner]

I've been chasing the same type of issue in my E-body. Still vibrates over 55 even with clutch depressed or in neutral. Defiantly drive shaft speed. What I've checked. Aligned bell housing laterally and 90 degrees to the crank with-in .005". Drive shaft angles mirror each other at 1.5 degrees. 2 different drive shafts, balanced at dyno tech. Drive shaft runout less than .030". 2 different rear carrier assys, neither shake in another car. 2 different sets of axle shafts. Balanced rear drums. New engine and trans mounts. Only part I haven't swapped is the trans. It shifts better than any 833 I have ever owned and makes no noise. No vibration at all below 50 mph. Bad enough it loosens the shifter bolts in the trans. good luck
Doug

I had the same issue. '68 RR

Vibration at 65-70 mph. 2200 rpm (OD trans with 3:23 rear) Did not vibrate at 2200 RPM in 3rd or 2nd . That eliminated the engine and trans. Changed U-Joints, still vibrated.
Thought maybe drive shaft unbalanced but seemed unlikely since the same shaft for last 24 years
Took it to an old timer who does alignments. Still vibrates
Last, my Coker tires only had about 10,000 miles and good rubber.....
HOWEVER - the tires were 14 years old. Replaced tires with Uniroyal redlines. VIABRATION GONE

Just a thought