Vibration in driveline or motor/tranny mount ?

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TripleJackInGA

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Hey People -

I just picked up this 65 Dart 273/Auto, and it has a vibration in it. I thought it was a bad u-joint (ball & trunion), but I notice it vibrates somewhat when in park or neutral, although not nearly as much.
It does it when accelerating from a stop, and it's worst as you go from 25-35MPH. It makes the steering wheel vibrate, but the back of the car feels fine. When I played with it in Park or Neutral, and brought the throttle up very slowly, then back again, I feel a vibration in a specific part, but still, no clue yet.
I need to get under there and check out the ball & trunion (blooming onion?) and maybe jack up on the engine and tranny a bit and see if any of the mounts look bad.

Just curious if this is indicative of one or the other, because when I've had the u-joints go out in other cars before, it usually didn't produce a vibration sitting still in Park or Neutral.
 
Harmonic balancer maybe ? Busted rubber supports wont cause vibration. They thump when torqued.
Make sure its not the fan comming apart. Rare but happens.
 
Is that the original motor? Are you sure?

My '65 Barracuda had a bad vibration. I balanced the tires, replaced the ball and trunion...everything.

What was it? Turns out the newer engine (1969) mated to the 1965 transmission has a problem. The snout on the torque converter is smaller than the hole in the back of the motor. The snout needs to be perfectly centered or you'll get mad vibration! I assumed whoever put the motor in did this, but when I changed the motor I found out otherwise!

You have to add a small sleeve to take up the extra space. It's well documented in some books and other places. You can buy the sleeves or have one made, I had one made. The specs came from a book and are accurate. This solved my problem.
 
65s said:
Is that the original motor? Are you sure?

My '65 Barracuda had a bad vibration. I balanced the tires, replaced the ball and trunion...everything.

What was it? Turns out the newer engine (1969) mated to the 1965 transmission has a problem. The snout on the torque converter is smaller than the hole in the back of the motor. The snout needs to be perfectly centered or you'll get mad vibration! I assumed whoever put the motor in did this, but when I changed the motor I found out otherwise!

You have to add a small sleeve to take up the extra space. It's well documented in some books and other places. You can buy the sleeves or have one made, I had one made. The specs came from a book and are accurate. This solved my problem.
Click to expand...


crankspacerinfofrombook.jpg
 
I guess I need to get my *** under their and check some numbers on the tranny and engine.
Might be a good excuse to swap in a later model engine/tranny combo, or worse.

The thing does run really good though.
 
When ever I run into this it has been in the driveshaft. I would suggest that you take an indicator and check it for runout in the center and at both ends.
 
KSP said:
When ever I run into this it has been in the driveshaft. I would suggest that you take an indicator and check it for runout in the center and at both ends.
Click to expand...

Yeah, but there's a vibration when it's in Park/Neutral too and the shaft isn't spinnin'.
It's just more pronounced when you're moving through 25-35MPH.
 
Well, I finally got under the car and had a look at the numbers on the engine/tranny.
The casting date on the engine is December 1964, so that fits the build date of January 28th of 65.
The stamp on the tranny was 2466123, which says it's a 65 Dart/Valiant/Barracuda.
Based on these two things, I would have to say the engine/tranny are either original, or at least date correct.
After 65s & Caveman's revelation about the adapter ring if the engine is a later model, I was almost sure it would be that, but now it can't be.
I had a look at the engine mounts while I was under there, and they look fine. I forgot to look at the tranny mount, but I will.

I just find it terribly hard to believe that the ball& trunion or a u-joint could cause this type of vibration. It's more pronounced when in gear, especially the harder you get on it between 25 & 35MPH, but it's also there, although much more slightly, when the car is in Park or Neutral.

I'm going to have a closer look at it next weekend, and see what else I can find. Maybe it could be the harmonic balancer.
 
Sounds like it's NOT the problem we explained about. Must be your driveshaft, U-joint, wheels or something like that. Your slowly tracking it down..yay!

At least now you know you have a date code correct drivetrain.
 
I would also guess that maybe the previous owner rebuilt the tranny and used a later model torque convertor, and thus caused the same situation, but if the crank in my engine is original, then it has a smaller pilot hole, so a later model TC wouldn't even mate up to it (with the larger snout).

Hmmmm......my brain is melting.......
 
it sounds like engine balance is off. harmonic balancer, bad tq, broken/loose flexplate? it can't be driveshaft, u joints, mounts, tires since its in park/neutral.
 
How's the rubber ring inside your harmonic balancer or damper or whatever you call it?
 
I looked at it, and although it's not perfect, it's also there, and not missing in any significant portion.
I also watched the balancer while the engine was running, and there doesn't seem to be any wobble going on.
I need to get under and and have a look at the flex plate/torque convertor, but I'm playing with the brakes right now.
 
Holy cow, that explains the 2 flexplates that I broke. Im thinking the converter is the culprit. Mine revved very tight and was smooth throughout the range when it was all stock.
 
Sounds like a bad vacuum leak to me, Try sprayig some starting fluid around the manifold bolts and if it changes your RPM's at idle, there you go.
 
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