Stroker2112

Guys,
Put the 408 into gear in the driveway on my way to work this morning and got a LOUD clunking noise. At first, I thought it was the flexplate to torque converter connection....but that was fine. It was a LOUD clunking noise....killed the truck a couple of times. I limped back to my driveway and took the Trailblazer to work instead. Anyone have any ideas what this could be? The flexplate bolts are fine... nothing else looks wrong...

Stroker2112

Stroker2112

Spun bearing??????

GuitsBoy

iTrader: (4)

Was it repetitious and consistent? Was it at full engine speed or half engine speed? Was it only while the motor was in gear or was it the whole time?

Stroker2112

Guitsboy,

It was only when shifting from park into Reverse or Drive.....very little rpm....not continuos but LOUD! ...sounded really bad!.....I thought my flexplate had disconnected from the stall convertor or something...but that connection is tight. There are no leaks...metal shavings..etc anywhere to be found...my fear is that its in the tranny (its a new FLT level 5 4L60E)....

I guess I'll make the time to drop the tranny and examine closer......not sure what to look for though.....any other ideas before I starting tearing things apart?....

GuitsBoy

iTrader: (4)

If its only one loud clunk and not cyclical, id look into chassis problems first. Maybe a loose torque arm, or loose tranny mount.... or seriously worn out U joints.

Stroker2112

Guitsboy,

It actually did sound slightly cyclical...like a "clunk-a-clunk-a-clunka"...


Would the gears in the transmission make that noise if it had bad line pressure (I've got a mech Vacuum mod installed to the master brake cyclindere)?

Stroker2112

Well......it's the readend. Spider gears blew up....glad it wasn't the tranny. Thanks for all the great/free consultation.

Stroker2112