1985 3.03 speedometer problem
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1985 3.03 speedometer problem
My speedometer quit working. I replaced the cable and the plastic gear on the end of the speedometer and now it works on occation, usually after the truck has been running for 45 mintues. But, it bounces and does not register the correct speed - 45 mph when I'm doing at least 65. I can do a 35 mile trip and the odometer will register about 6 miles, thats how much it does not work.
I think I have a rebuilt Ford 3.03 trans. It has the two side shifting rods and originally it was a 3-speed on the column but was replaced with a floor shifter. The engine is a 300.
I can feel the gear that drives the speedometer in the trans with my finger but I'm not sure if it is made of metal or plastic. My concern is that the trans gear is either worn or has moved.
Any ideas on what my problem may be and how to fix it? Can the gear in the trans that drives the speedometer move? Thanks. <!-- / message --><!-- BEGIN TEMPLATE: ad_showthread_firstpost_sig --><!-- END TEMPLATE: ad_showthread_firstpost_sig -->
I think I have a rebuilt Ford 3.03 trans. It has the two side shifting rods and originally it was a 3-speed on the column but was replaced with a floor shifter. The engine is a 300.
I can feel the gear that drives the speedometer in the trans with my finger but I'm not sure if it is made of metal or plastic. My concern is that the trans gear is either worn or has moved.
Any ideas on what my problem may be and how to fix it? Can the gear in the trans that drives the speedometer move? Thanks. <!-- / message --><!-- BEGIN TEMPLATE: ad_showthread_firstpost_sig --><!-- END TEMPLATE: ad_showthread_firstpost_sig -->
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See part 37 in this exploded view of the top loader 4 speed. The 3 speed is similar in this area. I think you can see the gear via the speedo drive hole. You may be able to pull the tailshaft housing and replace it.
I couldn't find a 303 view, but a little searching might turn one up.
The other item is the speedo itself--is it known to be a good unit?
I couldn't find a 303 view, but a little searching might turn one up.
The other item is the speedo itself--is it known to be a good unit?
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Joined: Apr 2004
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Before tearing down, have someone turn the drive shaft or output shaft and if you can't see into the case, feel the gear as it turns. Watch out it doesn't eat your finger... You should be able to feel it turn, see if it stops if you put some resistance against it, and feel if it's smooth and even in diameter.
Check the driven gear to see if it's stripped or otherwise compromised. Ditto the cable, both ends.
It may pay to go over all this stuff again--I know you already did--to avoid the teardown.
Good luck.
Check the driven gear to see if it's stripped or otherwise compromised. Ditto the cable, both ends.
It may pay to go over all this stuff again--I know you already did--to avoid the teardown.
Good luck.
Laughing Gas
Joined: Aug 2008
Posts: 823
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From: Dallas, Oregon
Also use a drill to turn the speedometer cable and see if the speedo works smoothly. If it bounces and/or reads unusually low, then look for trouble in the cable/housing or speedo head itself.
Low/bouncing speedometers often indicate a bad speedo head, but the cable can be dragging, wind up, and release over and over again, resulting in the bouncing speed reading. Since you have a low odometer reading, too, I suspect that you are not getting the revolutions/mile. Since the old driven gear was eaten up, it usually indicates a problem with the speedo head or cable. The drive gear almost never wears out, and the transmission tail shaft would have to wobble around a lot for an internal transmission problem to eat up the driven gear.
Low/bouncing speedometers often indicate a bad speedo head, but the cable can be dragging, wind up, and release over and over again, resulting in the bouncing speed reading. Since you have a low odometer reading, too, I suspect that you are not getting the revolutions/mile. Since the old driven gear was eaten up, it usually indicates a problem with the speedo head or cable. The drive gear almost never wears out, and the transmission tail shaft would have to wobble around a lot for an internal transmission problem to eat up the driven gear.
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