So the speedo needle in my late model 260 started bouncing excessively the other day. The bounce range being 30 to 80 MPH. It works fine then bounces, back to fine etc, etc. So I took the speedo cable off at both the speedo and trans, it was well oiled and in what seems to be very good shape. I took it out of the sheath to check for cable damage and found none. I took the pinion gear out and it looks good also, 16 tooth no damage I can see. So...what's the deal, why the bounce. Is the speedo itself having an issue? Any thoughts?

I suspect in the speedo itself. I have had mixed results cleaning them.

Does anyone know of a place in Arizona that I can bring the speedo to for a repair

 

eBay is your easiest answer. 

7 hours ago, zdude1967 said:

Does anyone know of a place in Arizona that I can bring the speedo to for a repair

 

Not in Arizona, but a friend once sent his tach here: https://www.bobsspeedometer.com/

Thanks everyone. I reached out to Bobs speedometers and they referred me to a place in California( West Valley instruments). They need me to send the speedo in to see if they can fix it. Two more questions. 

 

#1- can you take the speedo out if you have a dash cover- the ones you put on if the dash is trashed.

#2 Anyone ever try the speedhut Z replacement speedo

Hope to hear back...thanks

#1 ..Iirc the speedo comes out from the front so.. but it is do-able..    #2 eh.. no.

7 hours ago, zdude1967 said:

Thanks everyone. I reached out to Bobs speedometers and they referred me to a place in California( West Valley instruments). They need me to send the speedo in to see if they can fix it. Two more questions. 

 

#1- can you take the speedo out if you have a dash cover- the ones you put on if the dash is trashed.

#2 Anyone ever try the speedhut Z replacement speedo

Hope to hear back...thanks

It is a PITA to remove the speedo with a dash cap. You may have to trim the cap with a dremel to get it out the front. 

I wired up Speedhut gauges in a 280 after the owner mounted them. The issue is that you still need to get the old gauge out. Then you have to decide how far you want to take replacing gauges since some of the ancillary features like the high beam indicator and brake idiot light are in different gauges IIRC. Still I wouldn't discourage the use of Speedhut gauges if you know what you're getting into.

Thanks everyone!

 

Edited February 12, 20241 yr by zdude1967

Hope I can still get some responses. I have some updated progress. I put everything back together and Lo and behold the speedo does not work at all. The nylon pinion was not damaged and the cable looked fine. I regreased the cable and put it back, checked the pinion it was fine put it back and  -nothing, the speedo does not move at all. I took the speedo cable end off at the tranny pinion and spun the cable by hand. My trusted assistant told me the speedo moved to about 20mph, did it again same thing. Hooked everything up and drove down the street and nothing, no speedo. So a few questions. 

 

• I am assuming the pinion is not turning since the speedo picked up my twisting the cable end
• If the nylon pinion is not destroyed then the pinion should turn,  is this correct?
• Is there any way it would not turn- it seems like it rolls into the gears in the tranny and if not too far in or out should turn...is this correct or am I missing something. 
• If I put the car in neutral and moved the driveshaft by hand and took the speedo cable off would I see the pinion keyway spin if it were working correctly?
• Could the gear the pinion works off of in the tranny be damaged...wouldn't that be evident cause the car would not shift right or something, the gearbox would be loose or hard to shift?
• Completely lost and frustrated over this

Anyone have any idea what could be going on?

Provided the speedo cable is properly indexed into the transmission, it should turn when the car is moving. You shouldn't be able to rotate the speedo end of the cable when its installed in the tranny barring the shafts flexibility. The drive for the speedo is a stand alone gear near the end of the output shaft. It could have a problem and the rest of the tranny would care less.

Edit:

As I recall the drive gear for the pinion is metal, maybe brass. The pinion is plastic. I would think the pinion would disintegrate before the drive gear. I believe the drive gear has a ball bearing under it as a keyway and snap rings on either side. Maybe the gear has move somehow to where they don't mesh? Does your speedo cable have the keys on it?

Edited February 21, 20241 yr by Patcon

Patcon-the speedo cable has a key on the trans side and a specific shape on the speedo side. I unscrewed the cable from the trans and spun it -the speedo moved. It does not move now that it is hooked up. Is there a way to see if the pinion moves while I have the car on ramps. So is what you are saying is the pinion has its own drive in the tranny that would not affect the tranny other then its impact on the speedo pinion?