"klunk", what the heck was that? - I've been hearing and feeling a "klunk" noise when I take off in my 1930 Hudson

[timecapsule]

2 hours ago, Highlander160 said:

Something is cooling since you state that it's a 1 time noise. Cpl hrs ok, all day not so much. Any noise in the drive system will "end" at the final point, the axle. I'll bet you feel it in the shifter and gas pedal too, yes? Having done such a thorough exam of usual suspects to find nothing, what else could shock the driveline with a clunk? Can you access the slide for the throwout brg easy enuff? If it were to stick a little the force could possibly send a shockwave down the line. You said all the mounts were good, so if the motor/trans can't move what can? Lots of force on the avg pressure plate. If the parts warm up a little then some clearance is gained. You can baby it to make it not happen as well. Raw thoughts...

I've given thought to your theory previously.  Like lets say for instance I was using really light oil in my differential. 10W as an example, and lets say it was even low on oil.  Lets also say my pinion backlash was way way too much.  The symptoms might make sense then,  The pinion and ring gear would be dry once the car sat for a period of time, and that excessive backlash could make a klunking noise, until the gears got covered in oil.  However none of that is true in my case, plus you would hear a deafening humming noise from the rear end if that was the case.  But something like that would explain the time frame, playing a major part in the equation.

[timecapsule]

Hey Edinmass : I'm curious how that Chassis Ear works.  Do you get under the car and strap the receivers in various places, and then go for a drive, and then they record sounds, that you would play back later?  Or maybe you watch the receiver for a flashing light associated with a particular transmitter?

After further reading it looks like the Steelman 60635-00 is only a replacement transmitter part for the 60635 .  It looks like Amazon Canada is offering a 61082 that sells for $478 CA.

 

Is the tool you have a Steelman or something else?  Those kind of numbers seem like the Stillman brand is the expensive one to me.

 

[Highlander160]

36 minutes ago, timecapsule said:

I've given thought to your theory previously.  Like lets say for instance I was using really light oil in my differential. 10W as an example, and lets say it was even low on oil.  Lets also say my pinion backlash was way way too much.  The symptoms might make sense then,  The pinion and ring gear would be dry once the car sat for a period of time, and that excessive backlash could make a klunking noise, until the gears got covered in oil.  However none of that is true in my case, plus you would hear a deafening humming noise from the rear end if that was the case.  But something like that would explain the time frame, playing a major part in the equation.

What made me think of it is that Packard and some others keep that area oiled with a Bijur system. What did the rest of the OEMs spec as service? A bronze bushing could hang up a bit at 1st, old greasy lube, etc. I would test it by having it in that cooled condition, ease out the clutch ( not running) and rock the car  in high gear, watching the clutch pedal maybe...🤔

Edited November 13, 2023 by Highlander160 (see edit history)