Metal clanking when accelerating at 65mph, 69 roadrunner 383 4spd.

[Beep69]

Maybe someone can help me solve my problem. Just installed my 383 after being rebuilt. Now when accelerating at 65mph a metal clanking/rattle noise appears from under the car near my feet. No noise appears when running through all the gears and accelerating below this speed. Any thoughts on what is causing this. Never did this before the rebuild. Thanks

 

[PeteyDaMan]

Just a guess but I'd check your throw out bearing

 

[khryslerkid]

Check your exhaust pipes, down pipes on back.

 

[Beep69]

Thanks for the replies. So strange only does it accelerating at 65. Not before snd i csn run through all the gears before 65 with no isssues.

 

[Fran Blacker]

Does it do rattle cruising above 65 mph.

 

[Beep69]

Thanks for the replies. So strange only does it accelerating at 65. Not before snd i csn run through all the gears before 65 with no isssues.

Yes

 

[Beep69]

Yes

Yes but i usually let off the throttle to make the noise go away so i have not gone much faster

 

[WileERobby]

As noted, check your exhaust, and check your engine mounts and also the trans mount.

 

[6PKRTSE]

I chased a vibration over 65 before. Tried or replaced everything. Wound up being the factory damper looked okay but was coming apart once inspected alittle better once removed.

 

[super-bee_ski]

Thanks for the replies. So strange only does it accelerating at 65. Not before snd i csn run through all the gears before 65 with no isssues.

Typically with a "Load" off, the differential can Clank...
upon de-eceleration....

 

[Mick56]

Check the inspection cover on the bellhousing

 

[69Bee]

Detonation...

 

[Macdon221]

Another vote for check the inspection housing on the bellhousing. Had the exact same thing.

 

[jamie]

Speedo cable. Unhook it and try again


Edit: accelerating at 65 oh maybe not

 

[Beep69]

Tightened everything and still makes a metal rattle clanking noise only in 4th gear and once i hit 65. Drives perfect unless i drive on the freeway but want to fux the issue. I recorded the noise. Any thoughts. Thanks

 

[Fran Blacker]

Tailshaft yoke bushing can do that.

 

[Wietse]

With the noise appearing on 65mph and above it sounds more like a drivetrain issue then a loose inspection cover, exhaust or throw out bearing??
Did you use the same drive shaft and U-joint shaft sleeve as before? Could be not balanced or something?

 

[Macdon221]

Remove the bell housing cover for just short drive...will eliminate that issue for sure. Tightening it wont fix it....many of these covers are mismatched for the proper TC. If you still have the noise...then it is not this 100%.

 

[Big Bad Dad]

Tailshaft yoke bushing can do that.

Pay attention to what Fran just told you. Your original post stated that the noise was under the floor, near your feet. I had a bad tail bushing once, not realizing they ever wore out. I remember hearing some banging under the car, and didn't know what it was. It got ugly to the point that it destroyed the bushing, the heat basically welded the slip yoke to the trans output shaft, and when the oil started running out, it caught on fire under the car! This was many years ago, right after I had re-installed the engine and trans into my 67 R/T which is pictured in my avatar. Yeah, the trans tailshaft bushings usually get ignored. "Out of sight, out of mind". (Get under the car, and see if there is any slop where the yoke slips into the trans.)

 

[Macdon221]

Beep69....Did you find your issue?