39mm Posted September 28, 2017 Share Posted September 28, 2017 1963 Riviera with dynaflow. The universal joints are firm, no play in them. The center bearing support on the drive shaft is firmly bolted and not loose. The transmission mount is intact and firmly bolted. This loud clunk only happens when shifting into reverse but not when shifting into forward gear. Has anyone run into this problem? Any guesses? Thanks. Link to comment Share on other sites More sharing options...
EmTee Posted September 28, 2017 Share Posted September 28, 2017 (edited) Excessive pinion lash? Another thought -- could the yoke splines be binding on the transmission tail shaft? It might be worth removing the drive shaft to really check all of the joints and grease the yoke splines. Edited September 28, 2017 by EmTee (see edit history) Link to comment Share on other sites More sharing options...
KongaMan Posted September 28, 2017 Share Posted September 28, 2017 You backed into the garage door? You said you checked the u-joints; that was my problem when I encountered this. Put it up on a rack or con one of your buddies to go under the car while you shift gears. You can probably hear or feel the location pretty quickly. Do you drive the car a lot? There's some chance that it could be something internal sticking from disuse. It might also be slop in the reverse servo, but I don't now how much noise that would make. Link to comment Share on other sites More sharing options...
39mm Posted September 28, 2017 Author Share Posted September 28, 2017 25 minutes ago, EmTee said: Excessive pinion lash? Another thought -- could the yoke splines be binding on the transmission tail shaft? It might be worth removing the drive shaft to really check all of the joints and grease the yoke splines. If it was excessive pinion lash would it only make this noise in reverse? I have put the car in neutral with tires off the ground and turned the drive shaft back and forth by hand and there doesn't seem to be more than the normal amount of play in either direction. Thanks. Link to comment Share on other sites More sharing options...
39mm Posted September 28, 2017 Author Share Posted September 28, 2017 6 minutes ago, KongaMan said: You backed into the garage door? You said you checked the u-joints; that was my problem when I encountered this. Put it up on a rack or con one of your buddies to go under the car while you shift gears. You can probably hear or feel the location pretty quickly. Do you drive the car a lot? There's some chance that it could be something internal sticking from disuse. It might also be slop in the reverse servo, but I don't now how much noise that would make. When you had the problem with u-joints did the noise happen only in reverse? The car has been parked for awhile but this noise was happening when I was driving it regularly. Thanks. Link to comment Share on other sites More sharing options...
KongaMan Posted September 28, 2017 Share Posted September 28, 2017 I can't remember; it was quite a while ago. It was a definite clunk, though. You could try dropping the drive shaft to see if it goes away, but Id try easier stuff first -- like trying to locate it before you take anything apart Link to comment Share on other sites More sharing options...
39mm Posted September 28, 2017 Author Share Posted September 28, 2017 13 minutes ago, KongaMan said: I can't remember; it was quite a while ago. It was a definite clunk, though. You could try dropping the drive shaft to see if it goes away, but Id try easier stuff first -- like trying to locate it before you take anything apart Yes easiest first but dropping the drive shaft seems like a good idea. I don't suppose it will fly out of control if it's stabilized in greasy hands. Or will it? Link to comment Share on other sites More sharing options...
RivNut Posted September 28, 2017 Share Posted September 28, 2017 17 minutes ago, 39mm said: Yes easiest first but dropping the drive shaft seems like a good idea. I don't suppose it will fly out of control if it's stabilized in greasy hands. Or will it? Unhook it at the back of the transmission, not at the rear axle. Link to comment Share on other sites More sharing options...
39mm Posted September 28, 2017 Author Share Posted September 28, 2017 1 minute ago, RivNut said: Unhook it at the back of the transmission, not at the rear axle. Thanks. Do you think that excessive pinion gear lash clunk would or could only happen when shifting into reverse? Link to comment Share on other sites More sharing options...
RivNut Posted September 28, 2017 Share Posted September 28, 2017 (edited) I don't know. The last time I heard of clunking when engaging a gear, the car had a cracked flex plate. Hope that's not your case. What happens if you put the transmission into low rather than drive? Edited September 28, 2017 by RivNut (see edit history) Link to comment Share on other sites More sharing options...
39mm Posted September 28, 2017 Author Share Posted September 28, 2017 3 minutes ago, RivNut said: I don't know. The last time I heard of clunking when engaging a gear, the car had a cracked flex plate. Hope that's not your case. What happens if you put the transmission into low rather than drive? No clunk in the forward gears. As to the flex plate. Not sure but this noise seems to be coming from behind me rather than from below. Link to comment Share on other sites More sharing options...
RivNut Posted September 28, 2017 Share Posted September 28, 2017 In my experience, you can rarely figure out where a problem is by sitting in the driver's seat. A friend of mine had a van that he swore had a bad rear u-joint in it. He finally took it to a shop and they found a bad from the wheel bearing. Go figure. Sounds travel through metal and you hear them where the insulation is the thinnest. Jack's van was a work truck that was well insulated and carpeted in the passenger's compartment but bare metal in the back. You'll probably not find the source until you get it on a lift and can have someone listen from the outside. Link to comment Share on other sites More sharing options...
60FlatTop Posted September 28, 2017 Share Posted September 28, 2017 Check the track bar bushings. The originals are 50+ years old now. Also look at the control arm bushings. If "someone" has had the car on a lift with the shocks disconnected and let the suspension travel farther than normal some rubber can be torn loose. Bernie Link to comment Share on other sites More sharing options...
OldGerman Posted October 3, 2017 Share Posted October 3, 2017 Hello 39mm, I have the Same issue with my 63. the noise is only with the car in normal operating temperature, not when cool. I've read in the manual that this is kind of normal, if not excessive. But what is excessive ? Regards Frank Link to comment Share on other sites More sharing options...
telriv Posted October 3, 2017 Share Posted October 3, 2017 The MOST COMMON problem is the idle speed is TOO FAST!!!!! Tom T. 1 Link to comment Share on other sites More sharing options...
OldGerman Posted October 5, 2017 Share Posted October 5, 2017 What a surprise, my Manual says 475rpm idle. I guess I have much more and will adjust and see what happens. Thanks for the hint ? Link to comment Share on other sites More sharing options...
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