Looks like the speedometer cable didn't fix my screeching noise in my Austin gasser. Got some good weather today and took it for a drive, and it immediately made the same noise, only even louder! I pulled the speedo cable and the driver gear, and the gear looked great. That leaves the drive gear as likely damaged, so I ordered a new one, and will tear the tail housing off once I have the part and see what's going on. Until then I just removed the speedo cable and all was quiet to drive by tach instead.
Have you tried to lube the speedo itself? I doubt you have a drive gear problem. It's probably a dry bushing in the speedo head.
A visual check would confirm damage/wear bad enough to make annoying noise, I'd think. You have a neat ride and have posted smart replies, so I expect you aren't all thumbs under a car. That said, were the gears meshed properly? I think there are different rotations for different sizes on the big offset driven gear housing. The small one just goes in, IIRC. I'd replace both gears if I were to pull the tail housing, just like lifters and cams together. EDIT: Looked for a start to finish tutorial on doing this job, and didn't find a good one. Lots of fragments and talking about specific issues, but nothing overall. While you are in there, it might help to outline each step and take pics. This will show the way and probably get tips or corrections on each step.
It's not the speedo or the cable as I put a drill motor on the end of the speedo and it ran up fine with no noise. Pretty sure that metal clip that locates the plastic gear broke the pin off when the previous cable melted, and now it's letting the drive gear turn on the tailshaft and making the metal to metal sound with the metal clip spinning on the shaft.
Yes, as I mentioned the driven gear looked perfect when I pulled the housing to check it. I ordered both gears, the O ring, and the drive gear clip, but betting it only needed the clip. It's always been off about 10%, so figured while it's apart I'd replace more than the clip and hope to get the gear ratio corrected also. I did the online calculator for my gear ratio and tire size to get the right drive and driven gear tooth counts.
Rusty at Speedometer Service in Colorado is very helpful with all things speedometer related. Plus he is an Alliance member Speedometer, Generator And Alternator Repair In Colorado Springs
Sorry I was typing fast with fat fingers I was at the veterinarians with a sick best friend, they are going to do surgery on my dog tomorrow.
As stated previously, I don’t think a drive and or driven gear would cause your noise. I also think it’s a speedometer issue. If the cable is too long when you hook it up it may be causing pressure on the magnet and making noise in the speedometer, so maybe two issues. The new parts store and internet ordered cables have been too long out of the transmission end and bottoming out in the gear, thus pushing into the speedometer and eventually damaging it. There should only be 3/4 to 1 inch of cable sticking out past of the ferrule on GM transmissions, no more. I’ve seen as much as an 1-1/4 or more sticking out past the ferrule on store or internet purchased cables. I know this sounds like me badmouthing for my own sake but I assure you that is not the case. Pic’s below shows a customers “ new cable”from a chain store. It was putting pressure on the speedometer and ruined it. I cut it back and re-squared the end for the customer. So to the OP check the length on the transmission end, and it think it’s still the speedometer making noise.
The speedometer isn't making any noise, and I can spin the cable from under the car easily and see the needle move with no noise. I wont know about the driven gear for now as I'm not pulling the tail housing until I get the parts. The issue began when my old speedo cable melted and the inner cable froze up. I put a new cable on the car that was a complete cable assembly for a '67 Chevelle as it was the right length and ends. But it still made the same noise as before. I think the little spring clip that indexes the drive gear on the tailshaft broke the alignment pin off. So that lets the drive gear spin on the shaft and the spring clip is metal, so making the metal to metal screeching noise and erratic speedometer reading. With the new cable, and the speedometer spinning up freely with a drill motor, I can't see how it could be anywhere else but the drive/driven area on the tailshaft. Wont know until the parts arrive as nobody around town had the little clip for the drive gear.
You could try to reach in the transmission with a small screwdriver and see if you can rotate the gear on the shaft, kind of like adjusting the star wheel on drum brakes.
No, the drive gear is way too far into the tailhousing to be able to reach it. I had considered taking the old speedo inner cable and cutting the last few inches off to slip into the driven gear to see what I'd feel, but I doubt whether it was good or bad that I could turn anything be hand. I can drive the Austin without a speedometer until the parts arrive, so don't want to tear into it and then have it out of service until I get the parts. We're just getting gorgeous spring weather here, and I'd like to use my car while the weather is good, and only have it apart for a little while after the parts arrive.
Just to double check your speedometer, hook up the drill motor and spin the cable again, only this time push the cable towards the speedometer. This is what to long of a cable does. If the gear is slipping, then the speedometer should have been erratic. Keep us posted
I have certainly had screeching issues related to speedometer movement/vehicle speed. I was able to narrow it down to two distinct sources ... in my case it came from either the passengers mouth (just before the pee started to trickle) or the spinning rear tires
Speedometer was crazy erratic. It sometimes read close, then other times read 110 mph when I was going 30 mph. Mostly read high, but jumped around various high readings.
It runs smoothly and steady with my battery drive drill motor spinning the cable. Doubt it would if it was the speedometer.
All fixed today! I received my new tailhousing O ring, drive gear and drive gear clip, and pulled it apart. The clip was indeed broken, and drive gear could spin on the tailshaft by hand. I ordered the new drive gear simply because my speedo has always read off by 10% and I figured might as well change it too. Got the new drive gear and clip installed and fired it up while it was jacked up and ran through the gears. No noise, so took it for a drive and no noise still. Went through some areas I knew had speed warning signs that flash your speed and it appears to be reading perfect now! A total success all around, and no embarrassing screeching anymore!
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