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HUB
09-06-2005, 10:07 PM
Can anyone suggest what the problem might be when a speedo behaves in this fashion? When my 1963 GT Hawk is first started up and out on the road neither the speedo needle or odometer moves a bit. After a half hour or so of driving the needle will start to flip up momentarily - just a quick little bounce every few minutes. Then after an hour or so driving the needle settles in wobbling between 20 and 40 mph when I'm running 50 to 55mph. The odometer is now turning steadily as well. Suggestions? Thanks.

gordr
09-07-2005, 12:01 AM
I think about the only thing it could be is that the worm gear is slipping on the transmission output shaft, and as the tranny warms up, some parts expand and get a bit of a grip on it.

Pretty well anything else would involve turning the bottom end of the speedometer cable while the top remains stationary, and you only get to do that ONCE.;)

If the car is an automatic, you should be able to remove the tranny extension housing without removing the tranny, and see for yourself. If the car is a manual or overdrive, best to remove the tranny first.

One thing you probably could do: with the car cold, jack it up, get it on stands (for YOUR safety), and remove the speedo cable adaptor from the tranny. That should leave a hole large enough to reach in with a finger to touch the worm gear. If you can move the gear on the shaft, then you have found the trouble. While you are under there, spin the pinion on the speedo cable by hand and have a helper watch to see if the speedo responds. You want to turn the pinion counterclockwise as you face the bottom end.

Gord Richmond, within Weasel range of the Alberta Badlands

whacker
09-07-2005, 12:01 AM
It sounds like the speedometer has hardened grease in it, probably was lubed some time in the past with a parafin based oil that has since turned to rock. It would respond well to being cleaned with a good solvent and relubed with (don't laugh!) whale oil, available at clock repair shops. Failing that, try using musical instument oil, like trumpet valve or trombone slide oil, available at any good music store.

royvaldez
09-07-2005, 01:27 AM
Hey, that happened to me. To fix the problem, I had to relube the gears inside the speedmeter. Anyway, keep the faith.

HUB
09-07-2005, 07:41 AM
Thanks guys - this gives me something to try - or I should say will give my mechanic something to try!:)

curt
09-07-2005, 08:07 AM
I cleaned the spedometer and lubed it , problem solved. I had the same luck as Wacker, it ran happly ever after.

Roscomacaw
09-07-2005, 11:56 AM
Some Stude speedos - like the one in my Transtar - have a little oiling port - just above where the cable connects to the speedo housing. Coupla drops of oil and it's good for years. In fact, that was the case with the Transtar about 10 years ago or so. Needle was erratic, would get worse in the course of a drive. Even started making a gosh-awful noise. I disconnected it for a time and when I had a chance to take the speedo out to see if it could be fixed, I discovered the little oil hole. A bit of 3-in-1 and it's been OK ever since.
Or, it could be as Gord's suggested, in the gears. The gear that fits on the end of the speedo cable is made of a fiberous material, like the engine's cam gear. I have encountered these that have had their teeth stripped off!:( IF you found that gear's teeth shot, you'd best test the cable and speedo to see if there's resistance in either one. The effort to work against sticking parts would cause the gears teeth to wear out.
BTW, the other gear that's on the tranny's tail shaft is metal. It's unlikely that it's worn.:)

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

gordr
09-07-2005, 06:23 PM
Guys,

Note that Hub says NEITHER the speedo needle or odometer move until the car gets a few miles on it. If the speedo head was indeed STUCK, and the bottom end of the cable was indeed being turned by the gears in the transmission, the cable would be twisted off in less than a mile.

Now the speedo may well need a little shot of oil, but the root of his problem lies at the other end of the cable, I'm sure. Could be a loose worm, or maybe a partially-stripped fiber pinion. In any case, it's not hard to check.

Gord Richmond, within Weasel range of the Alberta Badlands

DilloCrafter
09-08-2005, 01:39 PM
Does that Whale Oil come in a spray can?

1955 1/2 Ton Pickup

whacker
09-08-2005, 08:22 PM
DilloCrafter, I have never seen it in a spray can. That doesn't mean it isn't available that way!
Gordr may very well be right here tho as it sounds like something is sure slipping somewhere in the setup. It may be that it requires enough heat for the parts to swell enough to grab and start the movement. It could very well be at the tranny end, or it could be that your drive cable is shot and is unwinding within the housing. At any rate, one of the universal cables will work just fine to replace the Studebaker cable and after forty years it is probably due for replacement anyway. Be sure to use all the lube that comes with the replacement cable (graphite, I think). When you do that, you can check the fiber drive gear at the transmission end and the instrument itself at the dashboard end.