Repositioning the speedometer cable

[MIPS]

I have an aftermarket cruise control fitted to a non-cruise Eagle, so it's the one long speedometer cable from the transfer case to the speedometer. I need to install a speed transducer on the speedometer cable for a Prince Automotive Computer. The transducer is identical to the one you find in your Eagle if you have factory cruise, but that uses a 2-piece cable set with the transducer in the engine compartment. I do have that 2-piece cable set (and a broken speedometer cable inside...) but I don't want to deal with pulling the cable out of the transfer case just to install the transducer, then remove it again after I've played with it for a while.
The Prince kit comes with a little 3" long extender kit so you can connect the transducer behind the dash and inline with the existing speedometer cable and I can see I can just barely make that fit behind the cluster but I can't seem to pull the cable back to the firewall. I just need 5 or 6 inches to make this fit and I can barely pull it back an inch. IS there something that holds it into the firewall?

[vangremlin]

I don't recall anything holding it to the firewall, I've pulled it back and forth before.  Here is a kind of dark picture looking behind the instrument cluster, you can see the speedometer cable and I believe it is pulled pretty close to the firewall.  Good luck!

[MIPS]

Yeah that's the same I saw when I was rebuilding the headlamp harness but I could not push it back. Even grabbing the sleeve from the engine bay where it comes through the firewall behind the brake booster it would not pull back. This was especially annoying because when reattaching the cable to the speedometer not being able to push it back more than half an inch meant the tip of the speedometer cable was a fight to get that last 1/4" so it cleat the connector would go in the hole. (and it's plastic, so you are trying not to snap the end off while bending things to make it fit.)