This noise started about a couple of weeks ago only makes it when the car is moving. Doesn't make it so much when the car is in high, but when you stomp down into low it makes this sort of hollow banging sound. I've looked for things around and under the car that could account for this noise, but haven't found anything that even remotely make that sound. So I go to thinking, if it is a hollow banging sound, happens only when in low and then only sporadically (but may get worse over time) there is only (I think) one place it could be coming from...the pan. When listening to the engine, it sounds nice, listening under the car it sounds also good...but when you get level with the floorboards, it makes a real racket... and when you do get into low it hesitates to move for a bit...I'm wondering if a slipping clutch could account for this noise...has anybody else ever heard a noise like this under those conditions before? If it is the clutch, do I readjust the disk fingers or try and reset the linkage on the outside? Or both?
I'm not an expert by any means Martin, but I don't think a slipping clutch would do that in low. Maybe you have a cracked/broken low speed drum?
Martin, The clutch should only be operating when you are in high gear. Low speed is actually controlled by the "brake band" on the Low Speed Drum. A good look around the Low Speed Drum would be a place to start.
Thomas, high gear nothing is operating, clutch or band, that's direct drive, so a low gear noise could be of several things from the diff, to the triple gears or anything in-between when stomping into low.
I'll check the drum, but this noise is sporadic, but it is getting worse...the noise isn't coming from the rear but from somewhere up front...but just to be safe I'll check the diff also.
The triples and the drums were all rebushed and reamed to tolerance when I rebuilt my trans last year, and I know it's not the magnets or coil ring because the magneto is still working.
Car starts easy, runs nice occasionally back fires, but that more mixture than anything else (I think)...I even checked the wishbone figuring it could be rattling in it cup...but its tight and wired, so that's not it either...Hard to believe it would be the drums though...I'm running wood bands and they usually char before they hurt a drum.
Which leads me back to the drive plate and the clutch fingers...or maybe even the outside linkage...but I've never heard a noise like that from the outside linkage going soft (wearing around the "L" piece or making the clevis it fits in oval rather than round).
One thing I forgot to mention...it doesn't make any noise until it is up to temp or just a bit higher...I tested it yesterday and everything was fine until the motometer showed red in the circle...then periodically it would make that banging noise. Usually when transitioning from HI to LOW. Once in LOW it didn't make the noise, but will sometimes make it in HI.
Chasing noises can be a challenge. I found the culprit to be a broken retention tab on a carriage light lens.
Yours will not be so easily fixed I'm thinking.
Possible issue with U-joint?
In neutral, reverse and low the transmission gears are turning. In neutral they are running freely, in low and reverse, there is pressure transmitted through the gears. The bands contract on the drums and hold them from moving so the transmission moves the car. You say when you stomp it in low the noise gets worse. What about stomping it in high? or hill climbing in high? How does it sound when stomping in high?
From your description, I would suspect the noise is coming from the triple gears. Maybe the bushings are worn or worse they are loose in the gears? You can check for looseness by removing the inspection plate and trying to move the gears around by hand. They should be somewhat snug from wobbling back and forth, but will mot be tight on the shafts. Also check the wear on the gears themselves. Anyway, my first suspicion would be the transmission. I think if the problem were in the engine or rear axle and u joint, you would also have noises in high gear.