Speedometer and odometer conversion, 1962 Olds 88

[gregleck]

I have my 1962 Oldsmobile Dynamic 88 in to have the transmission fluid changed, and bands and screen checked.  The speedometer and odometer had just stopped working as well so I asked that to be looked at.

 

A very small leak, at the Y yoke, is present.  Mechanic could not add fluid due to a mud wasp which had packed the breather tube with, what else, mud.  This was cleaned out.

 

At some time in the past, a previous owner had converted the speedometer and odometer from the original mechanical set up to one which uses magnets on the drive shaft and a sensor.  The theory is that the speedometer gear, which is at the rear of the transmission housing, broke off and slid up the driveshaft.  Rather than fix this by disassembling the transmission, the previous owner converted the system.  A plate is covering the site of the gear but the mechanic did not remove it to look.

 

The magnets were found stuck to the bottom of the car, instead of the driveshaft, and the poorly made bracket to hold the sensor (aluminum can and zip tie) was broken.

With a newly fabricated bracket, and the magnets glued to the driveshaft, the speedometer and odometer still failed to work.

 

Ideas, anyone?

 

Thanks,

 

Greg

 

[dlh61olds]

Make sure the leads are sound and have good connections.

 

The magnets must be almost touching the pickup when the drive shaft is turning.

This makes for a very touchy adjustment, the pickup will tear the magnets off if contact is made

(magnets sticking to floor is a good example).

 

Keep trying, you will get it right eventually barring some other problem.

 

Make sure the pickup is to the side of the driveshaft because there is some movement up and down as  the rear suspension flexes. .

 

Good luck, Dave

[TexRiv_63]

Not sure about the 62 but on 63 and 64 full size cars the speedometer cable attaches to the left front wheel, not the transmission. The magnet and pickup thing sounds like an after market cruise control setup.

[rocketraider]

62 speedometer drove off the transmission. I was thinking same thing about an aftermarket cruise system.

 

I know the 62 speedometer drive cable is an unusual beast in that it has a 90 degree metal sleeve at the speedometer end. Possibly the cable failed, unable to find a new or even good used one and this magnetic thing was installed?

[gregleck]

<<Possibly the cable failed, unable to find a new or even good used one and this magnetic thing was installed?

 

I think that is exactly what happened.  Perhaps the cable, or perhaps the gear inside the housing failed.   Installing this device was a cheaper and easier method than fixing the original problem.

 

I think I am going to have to get the car up on a life and poke around some more.

 

I have the 1961 shop manual, and the 1962 "supplement (1/2 the thickness of the 1961 volume) but I can't find much in either of them about the speedometer, apart from a table of axle and speedometer ratios,  and speedometer head and cable

removal.