Clunk noise when shifting upwards

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I'm thinking it's internal "valve" it doesn't do it until the car is completely warmed up. Once it's warm it does it at low rpm's only or getting off the gas abruptly. "Going in coast mode" ;-)

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I think what you have here is a battle between the three pressures that are involved in commanding a 1-2 shift.The vehicle is traveling at a road speed where the Governor pressure is combining with line pressure to ask for the shift to occur. Your throttle pressure, however is preventing that. Until you lift off the gas.Throttle pressure immediately falls and governor pressure commands the shift. This is how it works. Now, you can modify the valvebody to get a better balance for your driving style, or you can modify your driving style.Lift foot upshifts very often produce a feeling or sound that can be interpreted as a clunk, especially if there are worn parts after the tranny. The easiest adjustment is on the throttle pressure. But you may have to trade passing gear as a previous poster mentioned. You could reduce line pressure at the possible expense of durability. IMO, the best way is to reduce governor pressure so that the trans will upshift earlier. This assumes that the other pressures havent already been monkeyed with.Hope this helps. BTW I think it was in 1973 thay chrysler introduced the Part-Throttle shift valve. Those trannies are nicer. AJ
 
I would be remiss if I didn't chime in. My b body does the same thing and I have replaced the u joints and checked the rear end, as far as I can tell this is normal just get used to using the throttle a little more aggressively like all the rest of us Canuks should.
 
I've had a 76 dart automatic for about 2 years now, that makes a clunk clunk noise and shakes the car whenever i shift into reverse or drive, its done it since i got it, hasn't gotten any worse. any ideas?
 
One other thing to check, as long as you are looking, would be to make sure the pinion nut is torqued. You have to unbolt the the rear u-joint and drop the rear end of the drive shaft out of the way to get to the pinion nut.
Mine came loose just a few weeks ago and the ring & pinion gears got chewed up a bit as a result and I had to overhaul my center section.
Just another thing to check...
 
Hey guys. Ive been thinking about this for a couple of days and think Ive come up with a theory.Some of you have noticed that there is some driveshaft rotation with the trans in Neutral and parkbrake applied or similar circumstances, right? Well,as I followed the chain of parts I concluded that most of that "slop" originates(open diff now) in the interface between the side-gears and the spider-gears. Imagine that the diff cover is off and youre looking into the case window. Imagine that the side-gears are anchored and cant move. Now imagine grabbing the ringgear and turning it back and forth, that is,pushing it up and then down. While doing this watch the spiders. They will be climbing the sidegears till they run out of room, then falling to the bottom of the sidegear and then climbing up again. Now, keep that action in your head for a bit. Going back to the lift-foot upshift, try to imagine whats happening.AS the car is accelerating, the spidergears are jammed up to the limit under torque from the engine. then as you lift off the gas a moment occurs when the engine goes into zero torque or even compression braking. Well the spiders drop down or even climb up the otherside of the sidegears. Then the shift occurs, and torque is definitely going negative(foot still off gas). I think all this spider action is producing the clunk. Of course under normal acceleration there is a continuous torque applied and no clunk is felt/heard. This is also why it clunks, going from Neutral to Reverse or Drive. So whats the cure? well number one is to remove and inspect the crosspin. They have been known to egg-out the case and also the spiders wear deeply into the side of the pin. Then the rest of the wear needs to be shimmed out; either thicker washers or extra washers or new parts. As said earlier this applies to open diffs only, and this is my theory as based on observing my /6,open-diff, Volare.----- So, any comments?
 
AJ/FormS said:
Hey guys. Ive been thinking about this for a couple of days and think Ive come up with a theory.Some of you have noticed that there is some driveshaft rotation with the trans in Neutral and parkbrake applied or similar circumstances, right? Well,as I followed the chain of parts I concluded that most of that "slop" originates(open diff now) in the interface between the side-gears and the spider-gears. Imagine that the diff cover is off and youre looking into the case window. Imagine that the side-gears are anchored and cant move. Now imagine grabbing the ringgear and turning it back and forth, that is,pushing it up and then down. While doing this watch the spiders. They will be climbing the sidegears till they run out of room, then falling to the bottom of the sidegear and then climbing up again. Now, keep that action in your head for a bit. Going back to the lift-foot upshift, try to imagine whats happening.AS the car is accelerating, the spidergears are jammed up to the limit under torque from the engine. then as you lift off the gas a moment occurs when the engine goes into zero torque or even compression braking. Well the spiders drop down or even climb up the otherside of the sidegears. Then the shift occurs, and torque is definitely going negative(foot still off gas). I think all this spider action is producing the clunk. Of course under normal acceleration there is a continuous torque applied and no clunk is felt/heard. This is also why it clunks, going from Neutral to Reverse or Drive. So whats the cure? well number one is to remove and inspect the crosspin. They have been known to egg-out the case and also the spiders wear deeply into the side of the pin. Then the rest of the wear needs to be shimmed out; either thicker washers or extra washers or new parts. As said earlier this applies to open diffs only, and this is my theory as based on observing my /6,open-diff, Volare.----- So, any comments?
Click to expand...

Exactly, now add any sun gear to planetary gears to ring gear play (inside the trans), and any ujoint play to that and there ya go.
It adds up quick.
 
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