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Aggressive Drivetrain Shake??

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jzurek View Drop Down
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    Posted: May/19/2020 at 10:33am
Hi!
Not long ago, I replaced the oil pump in my 1965 327 Marlin. I had to lower the crossmember and raise the engine by the harmonic balancer in order to get enough clearance it remove it. After that, I had no issues getting everything back together, but when I drove it, I experienced an extremely violent shake coming from underneath the car. After driving it for a little bit, it seems that the shaking goes away, but comes back it I try to drive it when cold.

At that point, I decided to go in and torque the bands on the transmission per the specs called out in the manual, but that did not make a difference. The old transmission fluid was in good shape and the transmission looks very clean.
It did not seem to be a transmission issue as it did this whether I started from D2 (second gear) or D1 (first gear). It does not seem to be an engine issue either as I can rev it as much as I want and it does not do anything.

The dragging / shaking got so bad during one test run that I was revving the engine up and trying to accelerate, but it would not go past 10-15 mph up a hill. To me, it seems like it may be a bearing issue in the torque tube, maybe?

Has anybody ran into a similar issue? I want to troubleshoot this, but I don't even know where to start. Should I just pull the entire rear end / torque tube and start looking for loose bearings or u-joints?

I really need some help as I got this thing not too long ago and am really wanting to drive it haha
Thanks!

EDIT: I can also get a video of the car experiencing the shaking if that would help anyone



Edited by jzurek - May/19/2020 at 10:35am
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Someassemblyrqd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Someassemblyrqd Quote  Post ReplyReply Direct Link To This Post Posted: May/19/2020 at 1:46pm
Does it shake thru the rpm range while in neutral, standing still?

Have you raised the rear end off the ground, placed in drive and looked under the vehicle?  Have you inspected the attach point of the torque to the tranny for any gaps or anomalies?  Could you have stressed the tranny/torque tube when you raised the engine? Could the cross member and engine be misaligned?
Greg E.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: May/19/2020 at 2:34pm
you're not helping a 60 year old transmission by trying to force it to go as a troubleshooting tool. if you can't roll it by hand, it wont drive.
emergency brake on?
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jzurek View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jzurek Quote  Post ReplyReply Direct Link To This Post Posted: May/19/2020 at 3:15pm
Does not shake at all while sitting in park or neutral while stopped, I will try shifting it into neutral while it is shaking to see if it still does it.

I have not taken it out for any drives ever since I noticed this happening, I have only taken it out for "test drives" to try to identify the issue, and unfortunately I live on a sloped street so I have to take it uphill at some point.
Emergency brake is definitely off, car will roll freely.

Unfortunately, I do believe that I might've stressed it by lifting the engine Unhappy  I'll lift it up in drive and (carefully) accelerate the engine and see if I can see anything. In the meantime, I'll report back later today if shifting into neutral makes any difference on the shaking.
Thanks for the input!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jzurek Quote  Post ReplyReply Direct Link To This Post Posted: May/19/2020 at 9:43pm
UPDATE: 

Took a look under the car, couldn't see anything loose or mis-aligned. Took it back out for a quick drive to test it out. Once it started shaking, I threw it in neutral and the vibration went away. I also then noticed that the vibration only occurs only when the drivetrain is under load, and it also happened after going about 20-25 mph over a large bump in the road.

Once it was driven for about half a mile to a mile, the vibration seemed to have stopped completely, but I can't completely verify this as I don't want to take it out for a longer drive. It doesn't really feel like a standard vibration, like misbalanced tires or something, it feels like it is loading the engine when the vibration occurs.

Any ideas? I'm thinking that possibly the transmission / torque tube / differential are slightly out of alignment? I'm probably gonna drop the torque tube, realign the transmission on the mounts, and realign the torque tube to the transmission and rear diff, and check out the cv joints on the front of the torque tube, unless somebody can give me something else to try?
Thanks!


Edited by jzurek - May/19/2020 at 10:11pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dustintf522 Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2020 at 7:20pm
Interesting. My 67 rebel has a loud vibrating, shake at 65+ the faster you go the louder it gets. Hmm. Could the drive shaft be out of spec? A weight falling/rusting off? Hmm.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2020 at 7:36pm
I would be looking at the cardan (double u-joint) just behind the transmission in the torque tube.
The torque tube is likely the only thing keeping it in some alignment at lower speeds.
The more load you put on it the further it twists out of alignment. Drop the load and it settles back down into it's normal aligned coast position.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: May/20/2020 at 7:40pm
Originally posted by Dustintf522 Dustintf522 wrote:

Interesting. My 67 rebel has a loud vibrating, shake at 65+ the faster you go the louder it gets. Hmm. Could the drive shaft be out of spec? A weight falling/rusting off? Hmm.
May be better as a separate post than mixing with another.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/21/2020 at 6:16am
These driveshafts are small diameter and I doubt they would have, never saw, a balance weight (only seen a few so experts please correct this if wrong).
They could be the same problem, one just showing up and one about to fail.
They are 55 year old parts that have never had easy options to maintain, thus ignored. Grease, even though enclosed, is likely aged beyond the point of actually doing any lubricating.
One vehicle I own states lifetime lubricated part - the manufacturers "lifetime" as it turns out is 150,000 miles or 8 years. You just have to find the fine print.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: May/21/2020 at 7:26am
Trader most likely hit the nail on the head. The double-Cardan CV joint has a centering mechanism between the two joint that keep them aligned. When that fails you have a bad vibration. The joints were protected and last 50 years... and lots of miles. I've pulled 110K mile joints out that were tight as factory -- but flopped due to that little pin and bushing worn out due to age. There are no repair kits for it!! The only choice is to pull the shaft and take it to a driveshaft shop. They can lengthen the tubular part and make it a single joint. You won't notice the difference -- 56-61 Rambler V-8s used a single joint. The CV joint is supposed to be a bit smoother, but it isn't when it flops!! I think Galvin's sells a shaft already modified for a single joint if you can't find a local shop to do it. 
Frank Swygert
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