Changed transmission and valve body on My 67 RT. Speedometer worked fine before the swap. Now it's out for lunch. Checked the housing in the tail and the gears in the tail section turn when turning the wheels. All gears back there are looking good. Put a drill motor on the cable and the speedometer works. So I "assume" the cable and speedometer head are ok. All connections in the tail..speedometer to gears look ok. I was told the cable may still be bad because when putting a drill on it the inner cable moves in and out about an inch. Any help is appreciated. Thanks all. Thanks MOPARTS 727 Big block

When I installed a new cable two years I had the same thing happen. Evidently I tightened the nut on the cable too tight, cause after testing the speedo with a drill and left the nut looser everything has worked fine since

First thing I'd try doing is disconnection the cable from both ends. Then draw the cable up a bit from the passenger compartment, connect it at the transmission, then at the speedo. While you have it disconnect, also check to see of the end got bent.

Did you possibly change the clocking of the speedo gear housing? What year trans did you swap out and in? Some used a different style gear.

Went from a67 trans to 71. Tried different gears...Thanks

Didnt install a new cable Installed a different tranny

I'll try this at the tranny end as with a drill the speedo works but as said earlier there is play at the tranny line and "possibly" the cable is not going into the gear when screwing the connector on...Thanks

Took that assembly out of the old and installed in new

Did you clock it properly?

but is it snugged up [clocked] against the transmission output gear according to the tooth count of the speedometer gear in accordance to the speedometer gear housing markings ?

This might help.

yes....I'll ad a bit more..The person who built the tranny and helped me install is well known throughout Niagara County as the mopar guy to go to. I've known him for over 20 years ..he's 74 years old and has been working mopars since 1964. Builds all type motors. Built the hemi in My car. He shakes his head on this one and even though the speedometer turns with a drill and worked with the other tranny..He seems to think the play in the inner section of the cable is the issue. I'm going to disconnect at the tranny and if enough inner cable is exposed...I'll use needle nose to insure the cable feeds into the tail section housing. Thanks

Have you seen the speedometer move at all when turning the cable form the bottom?
If not make sure the square cable tip is engaged in the speedometer gear in the instrument cluster
good luck on getting this fixed and back into service

it will be interesting to see what the problem turns out to be.

Speedometer works with a drill motor connecteced so one would "think" from the cable at the tail shaft forward: everything is ok

Then it's either not clocked right or the wrong style gear or housing. That's all that's left. One other thing. Make sure the cable and housing are plugged into the back of the speedo solidily. I have run acrossed a cable housing that had seperated from the connector that attached to the speedo.

in addition to the above make sure the gear isn't "rounded out" & spinning on the cable end Keep us posted

Ok..speedo works better than ever. The connector was installed at the tranny but the inner cable did not make it into the gear head as when screwing the connector on, without making sure the center part of the cable made it into the recepticle, it backed off because of internal slack in the cable. I may need a new cable later but remember that the speedometer started to be a bit erratic before the tranny change. Now the connection is complete and secure: the speedometer works almost like new. Frustrating as it is like doing a document...cross all the "T"'s...dot the "I"'s....make sure all connections are connected. THANKS to all and MOPARTS for all the input.

glad it worked out for you Checker !