I'm about to lose my mind on this. Looking for others who have been there but have made it through the craziness.
The speedo gears on my car were wrong, I put the correct ones in - resolving my odometer issue, but my speedometer is still low by about 10mph.
When I reassembled my speedometer, is it possible I put the needle on too far causing it to be reading low? Is there an exact spot the needle needs to be aligned to? I've noticed a white line between the 5 and the trip odo reset button. Should it sit there?
Could the magnetic pickup be bad?

I"m really having a problem understanding, and have no experience with this exact issue.

 

Seems to me that it it's off 10 mph at all speeds, then your needle is probably the problem. If your gearing was incorrect, the error would increase with speed.

 

That's where it gets tricky. On my last test, after I changed the driven gear it was pretty much 10mph off the entire time. I decided to see what it read when my GPS read 75mph. It was reading around 60. So I'm not sure if it's that clockspring in there putting increased tension on it or something I'm not thinking about.

Ever since I pulled the cluster, the speed is a little jumpy at low speed <30. The cable has some free play near the transmission, which could be the cause. I also still have the cluster in by itself, have not bolted it back in or placed the trim/cover pieces on until I get this sorted out.

As I'm sure you can understand, I just want this to be right. Even if right, means incorrect. It's just frustrating that there is so little information.

 

I went on eBay to look at other speedos, and noticed something. The needles are all sitting at a different position than mine. Does anyone know what the true position the needle is supposed to sit at? I've asked a buddy for a photo of his as well. Thoughts? Bueller? Is that white dash meant as the place it's supposed to be?