gumtape

Hello,

I have recently acquired an '88 convertible, and the speedometer is sometimes extremely noisy. It sounds like a loud grinding that noise that will sometimes show up at a certain speed and then just go away. When it does show up, the speedometer needle becomes very erratic and jumps around. I'm thinking it's either a problem with the odometer, or the speedometer cable, but I'm leaning more towards it being an issue with the cable since sometimes it will sound and behave normally. I'm thinking that a new speedometer cable will fix it and silence it, but what do you guys think?

mazdaverx713b

iTrader: (91)

The speedometer cable is pretty straightforward to replace and still availablenew from Mazda. I would start by removing it and inspecting the inner cable for binding. It should move pretty freely by hand. Check the outer casing for any damage.

With the cable removed you can inspect the driving end where it threads onto the speedometer gear in the transmission. No need to remove the gear assembly from the transmission. If you suspect any failure with the speedometer cable, replace it.

If all is well and you do replace it and find that the issue persists, I would replace the speedometer assembly inside of the gauge cluster. You can find one similar in meager and replace your speedometer with a known good used one.

gumtape

Thanks for the reply. I'm going to take a look at the transmission end of the cable and see from there. I'll poke from the footwell to see how it's hooked up to the speedometer as well. I believe that it's possible to change the cable without removing the cluster and the surround? I'll see if I can get away with doing that when I get around to changing out the cable. I have a quick question about purchasing a new cable itself though, for my 88 convertible (5 speed), FB01-60-070A would be the part number to order? I'm seeing some different parts pulling up for either coupes or convertibles, but that part number seems to be readily available.

mazdaverx713b

iTrader: (91)

You can remove the entire cable assembly without pulling the cluster. The cable is attached to the cluster via a white clip. It has a release tab and comes off of the speedometer easily. A grommet for the firewall is all that holds it there, one body retainer, and its threaded into the speedometer gear. I'd have to look the part number up, but I think the only difference between the cables is manual and automatic transmission.

DaBrkddy

I have an '88 GXL that has had the speedo cable replaced with a new Mazda unit recently and it has the same issue, but only in cold weather. I recommend lubing the new cable before installing it or just lube your original one if it's still good.

I didn't do this with mine when I installed it and I am regretting it now...

That being said, the only problem with a "new" speedo cable is they are all presumably NOS and have been on a shelf inside a plastic bag zip tied in a ~1'ø circle for the past 25+ years... I think that's part of why mine has this problem.

YMMV. Good luck.