Roger L

My Speedo stopped working on 1966, 327L79,3:70 rear, 4 speed, needle was erratic then went to Zero
Dreading the situation I removed the cable end from back of Speedo and found the Blue Plastic fitting (see photo) was tightly stuck into back of speedo and separated from cable. I pried the blue connector out carefully.
Is this blue plastic part original or aftermarket replacement?

I now have a new speedo cable on hand so I connected it to back of Speedo and connected electric drill to other end. The speedo appears to be working and moving smoothly, so at least I know the binding appears not to be from Speedo mechanism, but most likely the blue plastic end binding up. I ran drill for several minutes putting some miles on odometer to make sure that Speedo mechanism wasn't the culprit. The new cable from LIC has a square metal on both ends no plastic part like what was removed.

I jacked up car, which has undercar exhaust and with very long pointed pliers was able to unscrew the transmission connection, between the exhaust pipe and transmission bracket.

I got that end of cable off transmission and it is all twisted up in a knot and cable broken (see photo) the other KNOTTED end is still in the transmission gear and I can't grab it to pull out.

So thinking of removing the fitting assembly retained with the one hex bolt and retaining clamp but don't want to go further until I get some expert advise

I need to call on your expertise.

1st- I would like to change the Speedo drive gear in transmission as I don't know if any teeth were damaged from this situation considering the force to twist the cable and break it and would prefer to only do this once. Is the gear plastic and what gear should I order for Muncie 4 speed w/ 3:70 rear. Will this gear fitting assembly come out when I remove the bolt / clamp? Will anything else fall out from removing it?

2nd-What else should I change while this fitting is out of trans are there any seals? Does this fitting and new gear just slide back in?

3-How the heck do I get up there to remove it, any tricks? Or must I have to remove either the right hand exhaust pipe or transmission bracket. Either one comes with their own issues. I hope someone has some tricks up their sleeve for this twisted up mess

4-Lastly can I put the new speedo cable to the gear fitting and use the cable to put it back into transmission.

Sorry for all the questions any help is appreciated
Roger

buns

I don't know what that blue thing is, I've never seen one before.
The speedometer driven gear is plastic. With a 3.70 rear end ratio, and stock diameter tires,will need the 22 tooth (green) gear.
Undo the hex head bolt and pull out the gear fitting. The gear will come out with it.
The gear fitting has an o-ring seal.

buns

In regards to the speedo gear. They also made a 22 tooth (silver) gear. It is larger than the green one. You will need to pull the old gear out and see what you have.

Roger L

Thanks Buns
I don't know what the blue end is either but was definitely the culprit for binding at the speedo as it has a shoulder and no space in cable end for it.
Over time it bound up the inner cable and drive gear kept turning it tight inside cable, I couldn't even pull inner cable out.
I will order both gears silver and green so it's on hand when I remove the fitting.

buns

You might be able to get them locally.
Part# for the green gear is 3860345.
Part# for the silver gear is 3987922.

Randy G.

I think that blue piece is from a replacement cable kit where you cut the cable to fit and glue/crimp the blue end on it which has the square end.

409/409

When you remove the "bullet" that the plastic driven gear is inserted in make sure you do it sloooowly. You can pull the "bullet" out and the gear may slide out of it and fall into the transmission. Ask me how I know!!!

Roger L

Randy, that makes sense as the blue part dimensionally was too long and bulbous to fit properly inside the speedo connector binding it up. The previous owner had car for 40 years and these gremlins continue to appear with great consequence. The inner cable is wound so tightly inside outer tube that it can't even be pulled out. I am expecting teeth missing from plastic drive gear when removed, hope no other problems.
thanks Roger

Roger L

409/409 thanks for heads up, now more concerned as the twisted knot of inner core broke behind fitting maybe it will retain the plastic gear as I remove fitting.
Looking at it again last night I think maybe easier if I remove right exhaust pipe from manifold to trans support as I can't get my hand up there to remove the fitting.
thanks Roger

409/409

Pull the bullet out slow and straight so that the diameter of the gear doesn't drag against the transmission opening. If the diameter of the gear catches the inside diameter of the hole you can pull the gear out of the bullet. I don't think it is a problem with smaller diameter gears but a larger diameter gear can catch on the transmission.

Roger L

I got it up on lift today, remove right front exhaust pipe for access to trans fitting. Carefully removed with great anxiety fitting as 409/409 advised and gear came out and was fully intact with no damaged teeth, the cable had severed at the square end. I had the two versions of the 22 tooth gear on hand. But to my surprise the gear in trans was 24 teeth. Always thinking it was 3:70 as I never checked it. So turning rear tire 1 turn drive shaft rotated 4.1 times. To my surprise the car has a 4:11 rear (not sure I am happy about that at this point but no plans to change over). Put it all back together carefully and Speedo works perfectly as checked against a GPS.
Thanks for advice.