Speedometer issues

Hi guys, i just bought a new speedo cable for the jeep.

Cluster is 5 years old, brand new, speedo work about 1 year before i destroy the cable, so since four year i wasn't working

Strange thing, i did some test ride and i have a reading of 50 mph when on my gps it say 40 mph. The strange thing is that i got 36" tire, so having bigger tire than oem the reading was suppose to be slower than the real speed. I'm still 3.73 ratio in the axle, same as i got the jeep.

So can it be a problem with the cluster?

Before buying another one, or a ratio adapter i want to make sure problem is not in t case of cluster....

 

Did you change the transfer case? The speedometer drive gear if different would do that. I would think if the cluster was bad it would read slow.

 

NO same transfert case as i got it.

 

The only thing I can think of is that the four years of rest on the cluster, it has collected some rust at the speed cup. I would connect a drill motor to the core and run the drill speed up and down to rotate the speed cup portion from 0 to 9 several times to loosen it up. this may cure it's ills.


















t

 

Good advive , i will give it a try

thanks