Well my 71 maverick started thumping when I switch from park to drive.. The noise sounds from where the rear end n the drive shaft meet.. It started happening after we added some shackles to the leaf springs.. I didn't kno how to put the car up n it kinda fell when u released the leaf spring bolt could that have damaged the drive shaft.?
sounds like a...bad U-joint...does it make the same noise when going from...drive to reverse? ...Frank
What Frank said...start looking at u-joints. Should be easy to check. Just get under there and twist and wiggle the drive shaft at both ends. There should be NO movement or wiggle at the joints.
Put in gear, emergency brake on and make sure there is no movement or wobble at each joint. You can usually look closely at the u-joints under the caps and see a little slop if they are bad. If not, start looking at the rear, as Bryant is leading... Pray for U-joint issues. Much easier and cheaper to fix.
Might be an engine or trans mount. Take a look at them. With the engine running, put the ebrake on, car in first, and rev the engine a bit. Have someone look at the mount and see if it separates (both sides). For the trans mount, get under the car, engine off, and lift up on the tailshaft, see if the mount moves or separates.
If your u-joints are bad, there tends to be a shake that shows up right around 45 mph. Did you add shackles to pick a sagging rear back up? ... not to jack the car up, just level it? Just thinking that if the leaf springs are really shot, you might be hearing the pinion hitting the snubber. Do you have a couple hundred pounds of stuff in the trunk? ... or something else really weighing the car down? .... mega-stereo?
