65 Speedometer works Odometer doesn't

[Bob Curry]

I have a problem on my 65 Corvette where the speedometer works (is off actual speed, but close), but the odometer and tripmeter do not work. Folks in my club think it might be a "spline gear?" that fits between the speeedo and odometer might be stripped. The local Chevy dealer doesn't carry parts that old, but told me that the "spline gears?" came in plastic and metal varieties. They had no contacts as to where one would get such a part.

Is the part available and can it be installed by a home mechanic?

Anyone with any info that would help as I would like to have the parts available to replace when I drop the dash..

[Jack H.]

Re: 65 Speedometer works Odometer doesn't

First check that you don't have a simple problem (cockpit issue)... The tripomenter resets by pushing up on the reset knob and turning it. If prior owners haven't periodically exercised the reset function, internal cable lube can 'puddle' and dry causing the spring loaded return function to mis-behave and the cable to 'hang' inbetween reset and run positions.

This will result in the spline gear failing to engage and 'could' result in gear clash + damage if not caught and corrected promptly. Test if you've got a simple fix situation by removing the cable, applying fresh cable lube and exercising it (in/out and rotationally) to make sure it's working smoothly.

Now, reinstall the reset cable take a short drive. See if the tripometer will catch and hold in its down/run position (you might have to physicaly PULL the cable down to loosen up the spline gear and get it to return to its drive position). If after several attempts at reset and exercise, you still can't get the tripometer to function, it's time to pull the speedo and have it repaired.

Parts are available from some of the catalog house (e.g. Dr. Rebuild) + there are United Delco dealers out there who do speedo/tach repair work and still have an inventory of spare parts. Once you've got the function working, remember to periodically 'exercise' it by resetting your tripometer and keeping the cable running smoothly...

[Joe L.]

Re: 65 Speedometer works Odometer doesn't

Bob-----

First of all, that gear is very likely your problem as you've been told by others.

Virtually all of the speedometer parts have been discontinued by GM. Most of the parts were manufactured by Delco Electronics. When they became part of the spin-off DELPHI, the management of that company decided that they didn't want to be in the business of making parts for old mechanical-type speedometers. That created a "vacuum" in the market since there was no other source for these parts.

I believe that some other sources for these parts have "risen" to meet the demand. I'm not too sure about it, though. Anyway, Dr. Rebuild carries some of the gears for the odometer drive system.

[Verle R.]

Re: 65 Speedometer works Odometer doesn't

If you decide you need to have the speedometer worked on, I have had great luck with several old speedometers I have taken to Speedometer Service in Tulsa, Ok 918-584-7698. When they still had such a thing, he was a GM authorized Speedometer and Tachometer service. He knows how to fix them and still has the parts. He is reasonable and reasonably prompt.

Verle

[Frank C.]

Re: 65 Speedometer works Odometer doesn't

Hi...I had one of my '63s speedo & trip meters rebuilt may years ago by an instrument friend of mine (the trip meter didn't work at the time). He repaired it but he didn't install the drive gear for the trip meter, rather he just taped it inside the housing because he explained the trip meter would just fail again because of a flex problem in the instrument panel (it can always be put together if I went to judging). Can anybody relate to this?