Speedometer problem

[salsa]

New to lat-g today. I have a 1973 Firebird with an anoying problem. The problem is the speedometer is not working right. The problem is, at rest or stopped the speedometer shows 40 mph and when accelerating it does not track right or should I say show the correct speed, it sticks and is not moving how the speedometer is suppose to. The odometer does work properly all the time and at all speeds. I replaced the speedometer cable and no change. So I ordered a new speedometer from classic industries and installed it and it does not work correctly either, it takes quite a bit of speed for the needle to move and does not appear to be showing the correct speed. Is my problem with the speedometer gear in the transmission? Is it difficult to change the gear at home myself? Any transmission experts out there that can steer me in the right direction? Looking forward to your help.

[awr68]

Welcome! I moved your thread in hopes that it will get an answer. :cheers:

[130fe]

What kind of transmission is in the car now?

[98ssnova]

more than likley it is the gear in the tranny was it rebuilt recently? You will have to experment with some diffrent gears till you find the right one unless this is the org. tranny then you should be able to just the year spec part number also are you using stock or aftermarket guages?

[salsa]

I bought the 73 Firebird in 2006 from a local who bought it in 75 as his first car. He ordered a new corvette so to make room he put it up for sale & I went for it. Stats 1973 Firebird Esprit, delux int. AC, PS, PB, AT, 350c.i. , the car shows 126k and the transmission is the TH350 and the car is a survivor with drivetrain in original condition. I have verified that only normal maintenance a repaint 9years ago have been accomplished. I live in Idaho so our dry high desert climate and the car graged alot of those years kept it in very nice original condition and rust free. Can I replace the plastic gear in the transmission easily? Will I have a big fluid mess if I try to replace the gear myself?

[salsa]

I replaced the complete speedometer in the dash with a new restoration assembly from Classic industries, the face of the new unit was not an exact match so i boxed up the original for now. It appears there are 10 different gears in the catalog so my thought was to pull the old one out and count the teeth so I can order the correct one. Anyway this is one task I have never attempted before. See attached photo of trans & cable.
Thanks, Max

[98ssnova]

I don't think it will leak fluid but it has been awhile since i did mine. Just throw a drip pan underneath.