Speedometer dead, 1975 Power Wagon

[Kern Dog]

In 2013, I got this truck....

By the condition, you can tell it was an "Old Man's Truck". I stripped off the trim, camper shell, flares and did the bodywork...

I added the 1977-78 grille because I like that style better.

It is an original 440 and was originally a 4 speed. I converted it to a 727 automatic.

Since the transmission swap, the speedometer has not worked. The transfer case is original and the speedometer cable attached there originally and after the swap. I put the end of the cable in a drill and confirmed that the speedometer gauge does work. There is something wrong with the drive mechanism inside the transfer case.
Who has experience with this? It would be nice to have a working speedometer.

 

[captainchrysler]

Cable:
Some times the cable doesn't engage the drive end at the trans. Take that apart and wiggle it around and slip it back in there. I've fixed a few like that. And if it's not too much hassle (gotta remove the cluster) confirm that it's fully engaged from the speedo end by trying to manually turning the cable with the speedo disconnected. If it spins then you still have a problem, might need a new cable.
Speedo:
About the only real way to check that is take it out find a square drive bit (you know the fancy set of bits that have all kinds of stuff that you never use, probably in there) that fits. Put that in a drill and give it a spin.

 

[65 sporty]

Does it connect straight to the transfer case or does it have a gear reduction adapter?

 

[Kern Dog]

It connects right to the case. I'll try to get a picture tomorrow.

 

[kiwigtx]

It might not be adjusted for the correct rear end ratio.....did you check that.

If the ratio is wrong the pinion on the speedometer drive will simply rotate without contacting the transmission drive.

 

[Kern Dog]

The weird thing is, the gears are stock 4.10, the transfer case is original. The cable might be too. I pulled the transfer case and adapter when I swapped from the 4 speed to the 727 but put the originals right back in the truck. Essentially, I just put the speedometer cable back to where it was but for some reason, it no longer works. I'm going out to look at it here in a few minutes.

 

[Kern Dog]

Here is a weird one.....

The truck does have one of those weird adapter boxes on it.

I've seen these a few times. Sometimes they are direct, sometimes that reduce speedometer speed, other times they increase it.

That fat hex at the end of the cable will not directly fit the transfer case. The box has to be there for this to all fit. It turns out that the problem was that the box wasn't snug against the case. I swedged it in place and drove the truck and the speedometer works.
EAST fix!

 

[kiwigtx]

Thanks for the update. I have never seen one like that before.

 

[65 sporty]

Glad you got it worked out