Driveline Vibration after motor swap, need expert help.

You might want to inspect and re-torque the torque converter fastners.

 

Tests were also done on jackstands, so that seems to rule out shocks.

I can do that. I'll post some in the morning.

I plan on having the 9" rebuilt while it's getting a posi, let's hope it's that.

There are no stock mounts available for a 460 in a 64 Galaxie unfortunetly, the custom mounts were bought from Dearborn Classics and not modified from how they arrived to me. I will have to figure something out if its the mounts.

 

Rear tire balance, broken belt, ply seperation? Wheel out of round or run-out? Missing balance weight? Maybe try running it on the stands again with the rear wheels removed.

Did that engine and trans combination need one of those big bob-weights bolted onto the back of it?

 

Any chance you can remove the through-bolts temporarily to see if the vibration goes away?

 

I know the weight you're talking about, and it wasn't on the truck, so it shouldn't make a difference. The tires are brand new and just balanced. Had a different set of wheels on the car before and it still had the vibe, so I'd say that rules out wheels.

That would be a last resort for me. I tend to think the bolts are needed, as I've seen aftermarket mounts separate on much smaller motors, I think the 460 is more than capable of pulling the rubber apart.

 

I mean temporarily for long enough to see whether the vibration goes away or not.

Surely there is much chance of the engine mounts coming apart if you run it up on axle stands or gently accelerate to 55 mph a couple of times?

 

I just read a thread 429 into an EDSELL used truck motor mounts.

 

True, it's just a pain pulling that motor, even just a small amount. I'm going to check the side to side alignment as suggested and if that checks out I'll start with the other suggestions. Thanks for the great responses. I'll keep ya'll updated.

 

make sure nothing that can carry harmonics is touching the frame or engine. example, trans cooler lines or metal fuel lines. make sure no part of the motor or trans is contacting the frame or crossmember. the engine should be setting on the mounts and not in a bind. your lucky that you can duplicate the vibration on jack stands which brings me to the next check. while the car is securely sitting on jack stands have helper run the car until the vibration is present. using a prybar, pry on the engine mounts and trans mount. if the vibration changed while prying on either the trans or engine this will get you into the ball park of the source of your problem. i have chased some realy nasty vibrations and seen all kinds of head scratching causes of vibrations and noises. bound up mounts, brake lines vibrating against firewalls, good driveshafts that turned out to be not good even after balancing and so on. best thins is get the vibration to occur and start pulling and puahing on stuff until you change the noise or feel it in a component. just be safe and watch for moving parts, drive shafts, wheels, belts and fan.

 

Are the ribs on top of the trans case touching the floor of the car? As the motor torques (even under normal driving) they can hit. My brother had a 460/c6 in a 63 galaxie briefly and they had to modify the floor. Also, check torque converter bolts.


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I like the way to you think. I'm gonna try this, probably loosen the motor mounts some and see if prying on them changes it.

It's possible it's touching and I can't see it. I know it's tight. It just doesn't seem like its coming from that area, it feels more like its coming from the driveshaft, as if it's wobbling very fast, but it could be fooling me.

 

My '60 Caddy is still doing this kind of vibration today after 15 years witha 501 Eldo engine in it. EVERY transmission swap I have done has this issue as well. SBC , BBC to 350/400 Turbos too. I'm also wondering if aftermarket clutches have issues with dexron 3 fluids.

The vibration I get is rummm, rummm- 2 per second it seems.

I have chased and chased the issues, went as far as rebuilding the motor, trying a 400 turbo, driveline balances galore from different shops ( computer of course. Changed out an intake thinking the improved overall flow would help, Changed out yokes, flipped 180 degrees. Tried a thicker flywheel that would not dare flex.

I noticed two things- The 700 r4 I have in there hides the vibration until it gets up to 65, and it seems the vibration is interupted and smoothed for a moment when the suspension is raised after hitting a bump.

EVERYTIME A RECENTLY REBUILT TRANSMISSION IS USED, THIS PROBLEM OCCURS. It has driven me nuts.

 

How tight are you pulling the u-bolts on the rear joint? The u-bolts can eggshape the bearing cup with anymore than 25 ft/lb of torque. If it has 5/16th u-bolt back them off and tighten snug 1 flat on the nut after contact. Real common to over tighten the u-bolts. There is my solution.

 

My 71 chevy Blazer does it at 65, my 67 chevy truck does it at 55. Both with rebuilt trannies, auto, after 1998. No one I know of has this issue, but me! Around here anyway. But then I hate vibes in an old car period.

People are at a loss as to what it is.

 

Never tried that! That could make it feel like bearings are going out! But with little room, how would I check the torque properly?

 

I'm sure they are torqued correctly. I've worked on lots of cars, changed u-joints myself on two different cars, changed clutches, transmissions, motors, heads and never had a problem or vibration with any of them. I've been working on cars since I was 14 and I'm 30 now. I'm usually the guy helping my buddies figure things out, thats why this is so frustrating. I'm supposed to be the one figuring this out, lol.

 

kinda sounds like the drive shaft isn't long enough. how much free play at the yoke is there?

 

Only thing I remember hearing about in 460 Ford V8 and vibration is incorrect flywheel. There are at least 2 different flywheels. We had the problem in a early 80s van after the engine was rebuilt and reinstalled and solved it with a different flywheel.

 

Have you check the pinion angle compared to the output shaft? They should be equal but opposite, with about 1 degree down on the pinion shaft to account for spring wrap under load... example, trans shaft points down 3 degree, pinion shaft should point up 2 degree. The pinion angle changes with up and down movement, so it could be correcting on the bumps for you.

 

I didn't have any issues like this either until the late 90's. Up til then I changed out everything I could to save money,, never had a vibration epidemic like I see now.

The other thing I never did was play with the pinion angle on the rear of the Caddy. The problem has occurred with 2 peice driveshafts, one peice -----I HAVE thought about one of those driveshafts out of a 70's Caddy, with that double u-joint end.

 

No, haven't tried that.

 

I'm hunting here too,, I read the entire post and it appears to me that all has been checked. Sometimes when new joints are put in they are still in a bind,, if the front is snug on one plain,, that will cause the vibe like you discribe. The tight u-bolts will leave needle impressions in the crosspin surface. I'm just going on past experiences.

 

Drive shaft has been measured and lengthened by driveshaft shop. It sits exactly where it was in the truck now as I can see by the oil seal wear pattern (shiny part)... it was about 1" too short before so I thought that was it, but it made no difference once lenghtened.

Engine and trans was pulled from the truck and never unbolted or separated. Complete unit was installed as pulled. Ran perfect in truck, so nothing motor or trans related should apply in my mind.

 

Very frustrating for you sir, Did you try loosening the bolt thru the gear box mount, as someone else suggested? Is that mount rubber or hard nolethene material. Can you slip some rubber about 1/4'' thick between the hard mount and the mounting crossmember, just to try???
Hope you get it sorted, Please let us know when you do. Good Luck.

 

the most probable thing to have changed in my mind is engine angle, that seems to confuse a lot of guys. my 2 cents only, free

 

This is getting to be one of those wild goose chase type of threads .
Im quite certain that there are well over 100 moving parts in your drive shaft .
Im also quiet certain that "new" does not mean " good" anymore .
I'm more than reasonably certain the humans at the drive shaft shop are capable of making mistakes, installing bad parts, or installing them incorrectly.

If I were you I'd take the driveshaft to another shop, and have it checked.
If it was mine I would personally install different u joints myself.


Here's a little story about a beautiful old Pontiac many years ago...
Pay attention to the engine angle and the ujoint working angles here.
I got some new tires for it and they were about 2" taller in the rear and 1" shorter in the front.
The rear needed a slight suspension lift to clear the rear tires ( about 3/4")
Many months passed before the car went back on the road while the beatification process continued.
Once out on the street again, the strangest vibrations at 55 started .
Many discussions with mentors lead to no conclusive answers but plenty of ideas, however I neglected to tell them about my newly acquired rubber rake at that time.
After weeks of lamenting over everything possible under the sun I talked them all into going for a ride to experience this first hand. All 4 of us pile in my ragtop and go for a sun filled Sunday afternoon cruise. I made my way to the highway and finally get up to 55 mph. Much to my surprise there is no vibrations its completely gone and "smooth as silk on a shaved pussy" to quote one of my mentors. So we return to the gathering point and discuss this further. Of course vibration is now all in my head according to them.

At this point I tell them everything I did over the entire beatification process including rubber rake tires and suspension lift.

Bing !!! Light bulb moment 30 years ago - Bing !!!
An extra 600 lbs of mentors reversed the rake enough to correct the driveshaft and ujoint working angles. The fix was to correct the engine angle against the rake via the transmission mount.

 

I fought this on my '70 p.u. Put a fresh 300-6 in and replaced the mounts. At that time, '89, the only thing I could find were parts-house imports. Made in India if I recall. It had the worst resonance, dull vibration, finally figured out it was the "Indian" mounts. I switched to the later 6 mounts and frame brackets, '79 style, and got rid of it. I believe you can use the original 352 mounts by drilling some holes for the block side. Just sayin'! Mike.

 

Here is my .02 cents worth...

Since you replaced the front u-joint, is here a chance that one of the tiny roller bearings fell over in the cup as you installed it, or is missing a bearing?

Is the slip yolk bottomed out on the trans output shaft?

Is the slip yolk rusted inside or twisted (look down the grooves to see if straight)?

 

This vibration came after you changed the eng/trans as a compete unit? After reading all the above theories, yes you may have changed the angularity but my thought would go back to the eng/trans. Is there a possibility you bumped the vibration dampner when installing the eng/trans causing damage there by causing a vibration? You said the engine had no problems in the truck it was removed from so if you didn't separate them all (i.e. flexplate, trans to enginebolts) would be eliminated. Check the dampner for rotational slipage and runout.

 

Post #18: I like the idea of adding shims to overcome the condition, if only to see if the vibration goes away. You may want to take another look at the transmission crossmember to see if you can factor some of the angle mis-match out of the equation. Slotting the motor mount holes is another easy thing.

Temporarily removing the bolts from the transmission mount and taking a short ride may tell you a lot of things.

Post #40: The C6 case may be hitting the floor pan. An easy check is to make up something flexible or use one of those plastic yard sticks and run it up between the case and floor.

From my experience with vibrations, a steady vibration that can intensify with speed is probably a mechanical interference somewhere. One that has a drone to it goes along with something in the driveline.

For entertainment, if it was my car, I'd take a 1 or 1.5 oz wheel weight, clamp it to the rear of the driveshaft and go for a ride. See what happens, rotate it 90* and go for another ride and so on. This will rule out anything with the driveshaft. even though it was balanced.

Bob