drivetrain shimmy '66 Classic

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   Trunnion, the rubber between  the torque tube and the transmission.
When you removed the crossmember how did you support the transmission?  I am thinking that the trunnion was an orginial 49 year piece of rubber might have gotten tweaked.  The purpose I think is to work as an isolator for the rear wheels as it pushes on the transmission.  If bad it might be allowing rotational forces from the motor or the rear wheels from a bump that would normally be locked in place.

Just an idea.

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gtoman_us Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: Jul/10/2007 Location: E. Nebraska Status: Online Points: 3871	Post Options Post Reply Quote gtoman_us Report Post Thanks(0) Quote Reply Posted: Mar/28/2015 at 1:49pm
	Trunnion, the rubber between the torque tube and the transmission. When you removed the crossmember how did you support the transmission? I am thinking that the trunnion was an orginial 49 year piece of rubber might have gotten tweaked. The purpose I think is to work as an isolator for the rear wheels as it pushes on the transmission. If bad it might be allowing rotational forces from the motor or the rear wheels from a bump that would normally be locked in place. Just an idea.
	Moderator - Emeritus Used to collect trophies, now I collect gas receipts and put on miles 1964 Rambler Ambassador Cross Country Wagon 1965 GTO 1931 Model A original survivor "Flat Roofs are Cool"

tubular_joe Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/14/2012 Location: Lynnwood, WA Status: Offline Points: 112	Post Options Post Reply Quote tubular_joe Report Post Thanks(0) Quote Reply Posted: Mar/28/2015 at 9:23pm
	Good idea. A second set of eyes is a good plan. Time to roll her up onto the ramps and take a good hard look around.

tubular_joe Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/14/2012 Location: Lynnwood, WA Status: Offline Points: 112	Post Options Post Reply Quote tubular_joe Report Post Thanks(0) Quote Reply Posted: Mar/28/2015 at 9:25pm
	You know, that's the only part that I couldn't find at all. You're talking about that boot that flexes between the tranny and the torque tube, right?

gtoman_us Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: Jul/10/2007 Location: E. Nebraska Status: Online Points: 3871	Post Options Post Reply Quote gtoman_us Report Post Thanks(0) Quote Reply Posted: Mar/28/2015 at 10:07pm
	Yep that is it. I was able to source mine from Blazers. Steve has them reproduced and it is a high quality part. You have to remove the torque tube to install it.
	Moderator - Emeritus Used to collect trophies, now I collect gas receipts and put on miles 1964 Rambler Ambassador Cross Country Wagon 1965 GTO 1931 Model A original survivor "Flat Roofs are Cool"

gtoman_us Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: Jul/10/2007 Location: E. Nebraska Status: Online Points: 3871	Post Options Post Reply Quote gtoman_us Report Post Thanks(0) Quote Reply Posted: Mar/29/2015 at 10:02am
	Also keep in mind that the flange on the torque tube "floats" on the rubber trunnion. The flange pulls and compresses the rubber which makes the transmission connection. Also when these start to break down the car does not want to track correctly down the road. You can probably loosed the TT flange and take a look to see the condition. Just another idea.
	Moderator - Emeritus Used to collect trophies, now I collect gas receipts and put on miles 1964 Rambler Ambassador Cross Country Wagon 1965 GTO 1931 Model A original survivor "Flat Roofs are Cool"

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19692	Post Options Post Reply Quote farna Report Post Thanks(0) Quote Reply Posted: Mar/29/2015 at 11:02am
	Everything is pretty straight forward as far as the mounts go. Maybe a bolt or two wasn't tight enough (heck, I forgotten to tighten bolts until something like this let me know!) and have loosened, but that's about all it could be. IIRC nothing will go in upside down or anything like that, or it doesn't matter (the side rubber mounts have no up or down, asymmetrical). The trunnion rubber is all I can think of. Hmm... check the truss rods, the angled rods on the axle. IF the anchor bolt is loose (front, where both attach) they could move and cause a shimmy. The axle ends have large rivets holding them to plates IIRC, but the plate could be loose or the rivets. Is this a V-8 car? The CV joint can cause vibrations, but that should be speed related, not just when you hit a bump. It's possible though, as the CV has a centering spring-and-pin in the middle. Maybe the spring is weak and a bump throws it off for a second or so? I doubt it, but it's possible. Six cylinder cars have a single u-joint, so can't be the problem on those. Both have a center bearing, but hat would cause a speed related vibration and not a bump induced shimmy. Can't see any way a bump could affect the center bearing.
	Frank Swygert

tubular_joe Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/14/2012 Location: Lynnwood, WA Status: Offline Points: 112	Post Options Post Reply Quote tubular_joe Report Post Thanks(0) Quote Reply Posted: Mar/29/2015 at 2:05pm
	If I recall, that trunnion rubber wasn't in very good condition. I will have to get a hold of Blazers and see if they have one. I'll take it to Dean Transmissions downtown. They were Rambler warranty repair. They fixed up the universal (CV) joints years back, did a great job. I'm going to double check all mount bolts, and will take a look at the angled rods attached to the axle, too, and make sure the truss rod nuts and bolts are snug, etc. When I pulled the (V8) engine I had the tranny supported with a floor jack with a piece of wood on it to equalize the pressure on the pan. At one time, the jack lost pressure and lowered it some before I could put dunnage under it. Maybe that damaged the trunnion rubber? Anyway, these are all great ideas. Thanks for letting me pick your brains.