Clanking sound

[William123567]

i have a 1970 f100 ranger xlt 390 with a automatic c6 transmission, when i start the truck up it runs like a champ and then i put it into r/d it starts to clank at low rpms but if i switch it to neutral and it will stop but starts as soon as i put it in drive or reverse it starts up again it is full with fluid. please help me i've put 2gs in the truck as is and don't wanna ruin it

[390Nut]

double check your motor mounts, tranny mount, carrier bearing for the driveline, and the rear axle for free play (jack the truck up, make sure it's in nuetral, and see how far you can turn the driveline without turning the wheels).

[William123567]

alright ill check that tommorow morning

[fordman]

sounds like a possible bad u joint

[68half/step4x4]

Is it doing it while stopped in gear with your foot on the brake also? I've seen and heard cracked flexplates make a clunking noise in gear and not make a sound in neutral. Let us know when you figure it out.

[DuckRyder]

I agree with checking the flexplate and Torque Converter bolts.

[mcarlson11]

maybe you have a loose exuast pipe mount, my dads truck makes a clanking becuase he has a loose pipe hanger, and it sounds like it is the tranny sometimes.

[fordman]

when you first put it in gear with your foot on the break do you here a clank. and then let off the brake and it starts kind of klank klank klank getting faster until the noise goes away or does it sound like a bird chirping as you go faster and then it gets quiter?