Rear Clunk
Thread Starter
Racer
Joined: Dec 2015
Posts: 421
Likes: 27
From: Los Angeles
Rear Clunk
Finally got to drive my Christmas Present to me last night, car was running good for 1 hour at aprox 75 mph on the freeway. Came off the ramp and made a left at light and there was a weird clunk while turning, checked u joints they appeared fine. Any thoughts
Le Mans Master
Joined: Feb 2014
Posts: 8,911
Likes: 5,458
From: Richardson Texas
How long had the car been sitting before you brought it home for Christmas? I would change the differential oil and add the correct posi lube and then go drive it in an empty parking lot in figure 8 patterns to get the clutches all nice and worked in. These old cars demand to be driven...if let to sit, they get cranky.
Thread Starter
Racer
Joined: Dec 2015
Posts: 421
Likes: 27
From: Los Angeles
It's been sitting at least 10 months, last night was its first real test, I had the diff seal replaced, new oil don't know if they added the additive, will call them Monday, in the mean time, do you think if the additive was added already do I just do figure 8's and how hard should I be doing them. Ian
Racer
Joined: Jun 2013
Posts: 337
Likes: 27
From: Fremont CA
It's been sitting at least 10 months, last night was its first real test, I had the diff seal replaced, new oil don't know if they added the additive, will call them Monday, in the mean time, do you think if the additive was added already do I just do figure 8's and how hard should I be doing them. Ian
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Le Mans Master
Joined: Feb 2014
Posts: 8,911
Likes: 5,458
From: Richardson Texas
It's been sitting at least 10 months, last night was its first real test, I had the diff seal replaced, new oil don't know if they added the additive, will call them Monday, in the mean time, do you think if the additive was added already do I just do figure 8's and how hard should I be doing them. Ian
Le Mans Master
Joined: Apr 2006
Posts: 7,033
Likes: 603
From: Limerick Pa
Why do I keep thinking the axle is walking out and pops back in when car straightens up.
The snap ring on axle shaft in rear came loose or broke?
The snap ring on axle shaft in rear came loose or broke?
Last edited by Bowtyeguy; Mar 5, 2016 at 06:40 PM.
Le Mans Master
Joined: Apr 2006
Posts: 7,033
Likes: 603
From: Limerick Pa
I was looking for the article but cant find it, I may be wrong. Lets see who else chimes in. I copied this from the Forum, not sure this is your problem.
. My passenger side yoke c-clip wore and broke off. With this condition with the wheels on the ground I could visibly see that the yoke was out of the pumpkin more than it should be, and able to see the shiny part of the yoke which is supposed to be in the pumpkin or on the seal. This condition was noticeable in turns, specifically in a right turn in that the missing clip allowed the yoke to slide out much further than having the clip would ever allow, then coming out of a right turn into a leftward turn, the yoke would slide back in and thump when it hit the carrier pin.
The issue of in and out play had nothing to do with a worn yoke, as the end of the yokes having nearly no wear at all. And was not an issue of trailing arm bushing, as they had been recently replaced. My issue was 100% because the lack of the c-clip allowed for the yoke to come out of the pumpkin.
Once the C-clip was in place, the excessive play was gone, as the only play allowed at this point was the .020 play between the end of the yoke and the carrier pin.... the yoke at this point could not travel out of the pumpkin past the c-clip.
. My passenger side yoke c-clip wore and broke off. With this condition with the wheels on the ground I could visibly see that the yoke was out of the pumpkin more than it should be, and able to see the shiny part of the yoke which is supposed to be in the pumpkin or on the seal. This condition was noticeable in turns, specifically in a right turn in that the missing clip allowed the yoke to slide out much further than having the clip would ever allow, then coming out of a right turn into a leftward turn, the yoke would slide back in and thump when it hit the carrier pin.
The issue of in and out play had nothing to do with a worn yoke, as the end of the yokes having nearly no wear at all. And was not an issue of trailing arm bushing, as they had been recently replaced. My issue was 100% because the lack of the c-clip allowed for the yoke to come out of the pumpkin.
Once the C-clip was in place, the excessive play was gone, as the only play allowed at this point was the .020 play between the end of the yoke and the carrier pin.... the yoke at this point could not travel out of the pumpkin past the c-clip.
Last edited by Bowtyeguy; Mar 5, 2016 at 07:02 PM.
Burning Brakes
Joined: Mar 2006
Posts: 829
Likes: 131
From: Spartanburg SC
Dry clutches in the posi unit will definitely pop when making a turn. And I'm surprised it didn't when backing straight out of the garage. Especially after sitting for ten months. Changing the fluid and adding two bottles of the GM additive is cheap and easy. Do this before you get too wrapped up in major mechanical issues. Keep it simple. Figure eights after the fluid change. The additive is cheaper on Amazon than the dealership.
Melting Slicks
Joined: Jun 2012
Posts: 3,115
Likes: 196
From: Wilton Ca.
Add the posi lube FIRST then top off with the fluid. Then go out and find an empty parking lot and do a bunch of figure 8's (both directions) ASAP.
Gary
Thread Starter
Racer
Joined: Dec 2015
Posts: 421
Likes: 27
From: Los Angeles
Ok did figure 8's this morning, and then went on a 2 hour round trip cruise up the coast, no clunk today, everything went good, thanks for the advice I never would have thought about doing the figure 8's. Ian
Melting Slicks
Joined: Feb 2007
Posts: 2,937
Likes: 163
From: OP Kansas
C2 of Year Finalist (appearance mods) 2019
I'm glad you got it fixed but if it comes back I wanted to mention an experience that I had. There was a clunk at the rear of the car that was intermittent and I checked everything and couldn't find anything wrong with any of the joints or whatever and what it turned out to be was the high hats ( I think that's what they're called ) were cracked and rotting away and needed to be replaced.