My father's 23 touring has been developing what appears to be some transmission noises that are starting to concern us. When depressing the low pedal into neutral and then into low there is a clunking noise. It only happens when you are slowing down to a stop and when the pedal is in neutral or on its way into low gear, there is no odd noise when in low, high, or reverse only in neutral and on the way into low. The entire engine/transmission was completely overhauled about 5 or 6 years ago and we usually drive the car more than 3,500 miles each year. We thought that the triple gears were getting loose on the pins or possibly low drum bushing wear?? This noise doesn't occur all the time, Today we went for a 90-100 mile ride and it was noisy for maybe the first hour or so. Any one have any ideas?
It could be anything in the drivetrain loose. Here are a few things to check.
1. Jack up the rear wheels and try to pull the wheels in and out. This will test thrust washers in differential There should be no noticeable movement there. Then have someone go to the other side, and try to turn both wheels in the same direction and reverse. This will indicate slack in either the differential, or in the ring and pinion gear. You will get a little movement here, but not much. It could also be slack in the universal joint.
2. Leave one of the rear wheels are still jacked up, pull the inspection plate from the transmission and have someone move the other wheel back and forth. Leave in high gear. Look at the drive plate between the spring and the brake drum. If the rivets are loose, you will notice some movement there. That could be a serious problem and needs to be fixed.
3. While the plate is off the transmission, work the pedals and see if you can see anything unusual such as front to back or back to front movenent of the transmission druns while the clutch is operated. That could indicate worn bushings or need for thrust washers between the clutch drum and the other transmission parts. You can also reach in and try to move the triple gears front to back or side to side to check for looseness and lastly go up front and take off the parking brake. try to pry the front pulley forward with a screwdriver (don't try too hard. You don't want to break anything) Then go and pull the brake lever and see if the pulley moves back when you do. That indicates worn thrust bearing surface in 3rd main.
Lastly, whatever is loose, needs to be fixed. The things I would think most critical would be rear axle endplay, Worn u joint, and loose rivets in drive plate. Also potential problem would be worn pinion bearing. If the pinion bearing were worn, you would have a loud continuous howl while driving and stopping. From your description I don't think the problem is the pinion bearing.
Here on the Ohio Jamboree this past weekend, my buddy described a similar symptom. As it turned out, one of his rear hubs was extremely loose on the axle shaft. It was to the point where there was a lot of play in the key/keyway. We tightened everything up and noises went away. Problem is, the axle, key and hub are shot now. Got him through the weekend by at least tightening everything up.
I checked the rear wheel nuts on the axle shafts, and the left rear was loose. We went for a ride today and it seemed to be quiet. All along I thought the noise was in the transmission.
Good. Let's hope the problem is solved.