'96 speedometer fix - help!!

My son's '96 has speedometer problems. This is a v6, 4wd, with a speedometer cable and a tach/speedo combination instrument cluster. I am now an instrument cluster/speedometer cable removal and re-install expert! Originally, it was bouncing severely and readings weren't accurate. I got it to run fairly smoothly, but still some bounce, and to read accurately.
When it recently got super cold, the speedometer failed completely. Haven't looked at it yet to determine why.
In the previous process, I think I finally determined that the speedometer head itself is worn and binding, and causing most of the bounce. I fiddled with cable length, routing, and tension, as well as how far into the head the cable would go. There were a couple of 'sweet spots' where bouncing was all but gone.
We would really like to get him a smooth working and reliable speedometer setup again. The question list:
Have people successfully converted to later year electronic setups? If so, how hard was it to switch over, source parts, etc. and is there a thread discussing the details?
There is one vendor who advertises "rebuilding" speedometer heads? Anyone know about this?
Is the actual head from inside the cluster swappable, and is it the same from a cluster without tach to one with?
Can I do anything to repair the head itself?
Hoping for responses ---- thanks!!

 

I've had three different vehicles, all different marquees, that had speedo go nuts.

One would be all jumpy, inaccurate and noisy. Mechanical. Found the retaining clip that held the drive end of the cable into the transaxle broken. New clip, all was good.

One read ok on the speedo, but the ODO was doubling/tripling mileage. Sometimes. A speedo head rebuild was the fix there. I'm not sure if they fixed mine and sent it back, or sent me an already repaired unit that they adjusted the odo on to match mine. But it was perfect for the next 100k.

The other was noisy/jumpy when cold. A new cable took care of that one. The unit was sealed, so it was impossible to lube the cable. Only $60 for the part, but a couple hours of fishing and fussing in tight quarters.

All that to say just be sure you have the root cause, then apply the appropriate fix.

I believe this is the outfit that rebuilt my speedo.

http://www.techni-car.com/index.php

Disclaimer, it was the late 80's, so my brain is being tested. Also, it was a GM product. Might be worth the effort to contact them though, even though they don't list Toyota. They may give you a reference, or their site could need updating.

 

Thanks for the reply, Bill. Knowing for sure the 'root cause' is the challenge. Wish I was 100% sure it was in the head. Using and aftermarket cable routed with gentler curves than OEM, I could drive the cable with a cordless drill and it would run smoothly. Verifying that the internal cable was not sticking out too much on either end, it would still bounce when assembled and clamped down.
Doesn't look like techni-car does old Toyotas, but I'll call them to be sure. Thanks again!