Looking for some help/ideas

I'm trying to swap my cluster (non tach) with a tach cluster on my 89 Lariat.
I got my first cluster swapped in, out of an 87 XLT standard, and it works, except for the speedo unit, which clicks and makes big jumps, like 15 mph to either side of actual speed, so I swapped in another one, out of an F250 with an e40d. All appeared good until like 5 miles in when it started doing the same thing. Tripmeter works, main odometer doesn't and the speedo needle does the same thing.

Any ideas? I'm getting tired of taking my interior apart

 

You're probably putting the cable in wrong :p

 

Cable is probably binding, from you pulling on the cluster to unhook it. Push it back down through the floor. Next time you have to unhook the cable take it off the transmission first and you can pull more slack to unhook it from the cluster.

 

put my old one back in and it works correctly :c

 

swapped back to a tach cluster, same thing, going right back to the original

 

I would try spraying some WD40 on the moving parts of the speedometer. You're not going to make it any worse.

 

we got her, if anyone is curious you can pretty much swap the tripmeter part onto the speedo head of a non tach cluster

 

looking to swap out my dash like you did 1989 150 custom with out tack for one with a tack any info from your swap would be great I see you got it working on your post did you have to change anything other then the cluster

 

The speedo and odo assemblies on the 2 clusters I took out were screwed, I managed to very carefully take apart my stock speedo/odo unit, removed the face, and the holes were already there for the tripmeter drive so I just pressed the additional gears in, besides, this way I get to keep my true(ish) mileage