Speedo adjustment
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Joined: Dec 2004
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From: Lawton, Ok.
Speedo adjustment
Hi all, on a 92 with a a518 auto do you change the gear like on the old 1's to change the speedo reading or is changed electronicly. My speedos reading about 7 mph to fast and no better guesser than I am I'm sure it gonna get me in trouble, thanks Terry
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Joined: Sep 2002
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From: Tucson, AZ
You can get different gears to adjust the speedo. Pay attention to how you install the gear "drive assembly" (for lack of a better term
) into the transmission - it has to be clocked a certain way depending on the number of teeth of the gear.
) into the transmission - it has to be clocked a certain way depending on the number of teeth of the gear.
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Joined: Dec 2004
Posts: 4,312
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From: Commerce, OK
I just got mine working. I have an 89 with a getrag tranny. When I got it the speedometer wasn't working at all and I found that the cable was unhooked. I hooked up the cable but then it ran backwards! After some searching I found a part was missing. It needs a right angle adapter which both reduces the ratio and reverses the spin.
After installing the $58 adapter I took it out for a spin with my GPS to check it's accuracy. I found that if I drove 10 miles on the GPS the speedometer read 10.4 miles. I took out the one bold (1/2 socket) which held in the gear and counted the teeth. I had 30 teeth so I installed a new gear with 31 teeth. Now the speedometer reads 10.15 for 10 miles on the GPS. I calculate that's as close as I can get. There are tick marks on the gear housing with numbers that show how to install it for a given number of teeth on the gear. The fork which holds it in will engage the slots on the housing to put it in the exact position.
I have a drawing I can email you if you want. Also you can use THIS proceedure to check what gear you need.
http://www.gaugeguys.com/ratiotest.htm
Edwin
After installing the $58 adapter I took it out for a spin with my GPS to check it's accuracy. I found that if I drove 10 miles on the GPS the speedometer read 10.4 miles. I took out the one bold (1/2 socket) which held in the gear and counted the teeth. I had 30 teeth so I installed a new gear with 31 teeth. Now the speedometer reads 10.15 for 10 miles on the GPS. I calculate that's as close as I can get. There are tick marks on the gear housing with numbers that show how to install it for a given number of teeth on the gear. The fork which holds it in will engage the slots on the housing to put it in the exact position.
I have a drawing I can email you if you want. Also you can use THIS proceedure to check what gear you need.
http://www.gaugeguys.com/ratiotest.htm
Edwin
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Joined: Jun 2004
Posts: 414
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From: Cape Coral, FL
A way to correct a speedo that has the right gear, but the needle is reading wrong:
I had to replace the small gear for the odometer. In order to do that I had to take the speedo apart and I also removed the needle. When I was done I left the plastic lens off and drove with the GPS. I set the needle correctly by pushing it max scale down or max scale up to get the needle to spin on the shaft and get it in the correct place.
Den
I had to replace the small gear for the odometer. In order to do that I had to take the speedo apart and I also removed the needle. When I was done I left the plastic lens off and drove with the GPS. I set the needle correctly by pushing it max scale down or max scale up to get the needle to spin on the shaft and get it in the correct place.
Den
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