Speedometer adjustment?
- Thread starter oino
- Start date
Screaming Metal
Active Member
Well, the pinion in the trans, thats driven off the tailshaft.... There is a small gear box that goes between the drive and the speedo cable that can be installed to correct this
Found this website that has the gears.
http://www.transmissioncenter.net/speedometer_calibration_______va.htm#350
Are they easy to change?
What has to be done to change them.
Hotrod46
Member
They're not that hard to change.
The driven gear ( the one that the speedometer cable connects to) is changed by removing the small housing that is in the side of the trans. It's usually held in by one bolt and a retaining clip. It just pulls straight out. The gear goes in from the back.
The drive gear requires that the trans tailshaft housing is removed. Depending on how much room you have, this probably can be done with the trans in the car. Pull the driven gear housing, remove 4 bolts on the tailshaft housing and pull the housing straight off the back of the trans. The driven gear is held on by a spring clip that you hold down and slide the gear off the tailshaft. If you have a trans with the rear mount on the tailshaft housing, you will need to support the trans while you remove the trans mount and housing. You will have to pull the friveshaft too.
Mike
The driven gear ( the one that the speedometer cable connects to) is changed by removing the small housing that is in the side of the trans. It's usually held in by one bolt and a retaining clip. It just pulls straight out. The gear goes in from the back.
The drive gear requires that the trans tailshaft housing is removed. Depending on how much room you have, this probably can be done with the trans in the car. Pull the driven gear housing, remove 4 bolts on the tailshaft housing and pull the housing straight off the back of the trans. The driven gear is held on by a spring clip that you hold down and slide the gear off the tailshaft. If you have a trans with the rear mount on the tailshaft housing, you will need to support the trans while you remove the trans mount and housing. You will have to pull the friveshaft too.
Mike
Screaming Metal
Active Member
As HotRod46 said....its all in the tailshaft housing....Look in your repair book on disassembly.
Also make sure the gears match....make sure the mesh and will roll thru each other....or you might wind up with alot of plastic shavings....
Its best to doublecheck....
Also make sure the gears match....make sure the mesh and will roll thru each other....or you might wind up with alot of plastic shavings....
Its best to doublecheck....
If I was to change to a electronic speedometer that can be calibrated would I still need to change the gears in the trans?
I kinda like this one from speedway.
http://www.speedwaymotors.com/Garage-Sale-Cyberdyne-LED-Digital-Speedometer,36811.html
I kinda like this one from speedway.
http://www.speedwaymotors.com/Garage-Sale-Cyberdyne-LED-Digital-Speedometer,36811.html
Gerry
Well-Known Member
electronic speedos have quite a wide range of adjustment, so you should be able to 'tune' it. Its always better to start from the original though. You could try it and if you cant get the right adjustment them swop over the gears, but this means it will have to be done in the car with the trans filled.
Gerry
deckofficer
Banned
oh I know.
Just want to make sure if I buy it. I'm not going to just have to change the gears anyways. that would suck.
deckofficer
Banned
Well, looking at the sender unit, it looks like it converts a mechanical signal to an electrical signal and if that is the case you will still need proper gearing unless the speedo unit can recalibrate by your input. If you are planning to go to an electronic speedometer, just choose one that uses a magnetic signal that is converted to an electrical signal. Just mount the magnet they will supply you to your driveshaft, and attach the sensor close enough to catch the lines of flux from the magnet. Now it will be easy to calibrate your speedometer no matter what future changes you might have in store for your ride, i.e., tire size changes, rear gear changes, etc. The easiest way to calibrate is with a GPS, but if you do not have one, just follow the directions for a "known mileage" type calibration.
Bob
Bob
deckofficer
Banned
I do believe all electronic speedometers should be able of user calibration no matter what signal pick up style they use. I looked at the ad again and they don't say, or even offer a pdf download of the owner's manual. But it would just make sense to allow the customer a full range calibration capability.
Bob
Lee_in_KC
Active Member
Other brands may have this feature as well, but Auto Meter speedometers have about the simplest calibration routine you could want. No special gearing for the sender. Once the speedometer is installed, you drive to a place where you can run a measured two-mile distance (I used mile markers on the Interstate). You pull over and turn off the ignition (assuming your instrument power is through your ignition switch). Then you hold the calibration button on the speedometer down while you turn the ignition back on, and the needle on the speedometer swings full range and back to zero to confirm it is in the calibration mode. Then you drive to the beginning of your two-mile course, push the calibration button again, then drive the two miles and push the button again at the two-mile mark. You're done! Doesn't matter what speed you drive it or whether you have to stop along the way (don't back up, though!). Most important point is the accuracy of your two-mile distance.
The worst calibration routine I have seen is on the Dolphin speedometer. It has something like eight dip-switches in the back of the speedometer that you have to flip on and off in various combinations until you get it right. I never did get my Dolphin speedometer anywhere close to right (don't get me started on Dolphin instruments! :foottap: )
Here is a dip-switch...
The worst calibration routine I have seen is on the Dolphin speedometer. It has something like eight dip-switches in the back of the speedometer that you have to flip on and off in various combinations until you get it right. I never did get my Dolphin speedometer anywhere close to right (don't get me started on Dolphin instruments! :foottap: )
Here is a dip-switch...
Duke
Member
I have used a few electronic speedometers, all the ones I used were programmable one way or another. The sender does convert mechanical to electronic. The output of the sender is measured in pulse's per min. Just be sure that the sender pulse's have the same range as the receiving speedometer. The attachment to the transmission is different for different transmissions, but usually not a problem. The other type of sender is the proximity type that measure magnetic tape on the drive line or in industrial use and some hall effect ignitions. the proximity sensor may measure rpm's by counting teeth or a hole drilled in the flywheel. Hope that didn't muddy the waters more - sometimes I get carried away hthedrama:
hthedrama:
I have a Garmin NUVI 255W and it has a sucktion cup mount just lick and stick.Where ever you're going just punch in the street address and city and state and it tells me the directions on the screen,the speed limit on the street,,how fast i'm going,the direction i'm going north,south,etc.The draw back is the womans voice telling me where to go.hehe.It also tells me how far to go before having to turn.Great product.Wouldnt leave home with out it.Also tells me where the nearest points of interets are and motels,gas stations.
putz
Member
In some areas there is no GPS signal like tree covered roads and in cities withtall buildings you can not pick up enough satellites to get the proper reading. They are a great idea though.
deckofficer
Banned
I have GPS also, but T is too noisy for me to hear her voice, and with no top, it is too bright to see, so just leave it in the cars/trucks.
Bob
Bob
deckofficer
Banned
