Oh I see we are having the same problem, I own a 1977
CJ5 with a
AMC 304 3 speed tranny, I had the motor rebuilt and I got this idea of changing out the speedometer so I would know how many miles was really on my motor a few years down the road.
I ordered a new OEM speedometer from Morris 4x4.com after I replaced it here is what is happening.
When the lights or parking lights are off my gas gage reads only half full I know thats right because I have filled the tank with gas, the gage will go to full and then float down to show between 3/4 and a 1/2 tank of gas.....with the old speedometer it do that.
When the parking lights or head lights are turned on this thing goes ape s**t the high beam indicator show my lights are on bright when I push the dimmer switch the lights dim but the indicator still shows HI beam
Both singal light indicators light up but the turn signal still work
Some of the cluster lights will not come on and I have replaced all the bulbs by the book
The little red light at the bottom of the speedometer also stays light I can't remember the name of that indicator light
Also I really don't think the speedometer is accurate eaither did don't bounch or nothing like that I just think I am going faster that it is showing
If you find thats guy's website would you please let me know
Thanks