Loud clunk when shifting from park

[mwelther]

I have a 68 Fury Convertible with 318 and auto tranny. When you first start the car using choke and it is idling high, when you shift from park to reverse or drive, it makes this loud clunk and the whole car jumps. Does not do it after car is warmed up or it is idling at low/normal.... Any ideas?

 

[BJS racing]

Sounds to me like you have a lot of play in the ring and pinion or your have some u joints going very bad! Start with checking the u joints.

 

[tallhair]

Concur with the U joints to check first. Jack it up in neutral safely on jack stands with rear wheels off the ground and inspect them and turn drive shaft and switch directions to see if you hear any clunk or movement in the driveshaft or pinion area. If they are old plan on changing anyway while you're at it.

you may also have someone operate the car and put it in gear while you are laying beside it and see if you can hear/see where it's coming from but be very careful and have floor jack under pumpkin with some slight pressure on it as back up to stands. MAKE SURE REAR TIRES ARE WELL OFF THE GROUND. And use HD quality 4 point jackstands not tube type.

Also try putting it in neutral when warming up the car and fill up the converter before going to drive or reverse.

 

[tallhair]

If you haven't already let's see some pics of that 68 Fury convert too !!!!

 

[66SportFury]

Should never shift the car into gear at a high idle. If you say it only happens when it's idling high, then that's why. Let the car warm up, and then shift it at normal idle speed. Anyone's car that's idling high with jump and make a clunking noise if thrown into gear.