Speedometer only sometimes works, replaced cable, worm wheel worn?? (1 Viewer)

[Ollie88]

Hey guys,

So my speedometer hasn't really been reliable (already since I bought the car 6 months ago). Sometimes it works, sometimes it doesn't. And if it does work it only picks up above a certain speed (> 15mph). I replaced the cable but instead it stopped working altogether. So I took out the worm wheel at the drive shaft and thought maybe it's worn and needs to be replaced?

See pic below. Can someone tell me if this one is worn? Is this common? Would love to get tips how to fix. Thanks!

 

[OPMACHINE]

That is the speedometer driven gear.

 

[Ollie88]

Thanks, but can you tell from the pics whether mine is worn and needs to be replaced?

 

[OPMACHINE]

Sorry, I don’t see and obvious flat spot in the gears and I don’t know the tooth engagement. I am sure wear is common because it is 40 year old plastic. I would put it back in and spin the rear drive shaft. You should be able to see/feel the driven gear spin.

 

[Ollie88]

Hmm okay so I connected a power drill to the cable from underneath the transfer case and my speedo works perfectly fine. Can I be 95% sure that I just have a worn speedo drive gear? If so: do the 16, 17, 18 teeth all fit? And given it's plastic, I assume the main drive gear is from metal?

 

[OPMACHINE]

Yes, that sounds logical. The dive gear is metal. The drive and driven gear need match or you will not get proper tooth engagement and it will chew up the driven gear. The driven gear should have the ratio stamped on it.

I actually have 5x18 driven gear that nobody has ever seen before.

 

[Ollie88]

alright, thanks I'll pull it out again and check what's on there! Thx for sharing the pics that's very helpful

 

[jimfischhp]

Hey guys,

So my speedometer hasn't really been reliable (already since I bought the car 6 months ago). Sometimes it works, sometimes it doesn't. And if it does work it only picks up above a certain speed (> 15mph). I replaced the cable but instead it stopped working altogether. So I took out the worm wheel at the drive shaft and thought maybe it's worn and needs to be replaced?

See pic below. Can someone tell me if this one is worn? Is this common? Would love to get tips how to fix. Thanks!
View attachment 3221380

View attachment 3221381

Unfortunately, I'm in need of similar help (not providing it). My speedo is dancing, gets stuck at speeds I've never hit, and generally is making a heckuva racket. I'm wondering if yours was doing any of the same stuff. I purchased a new cable (not installed, yet), but am wondering if it's a combo of the drive gear being worn (or worse...missing teeth) and a worn cable. Since all the noise is at the speedo, I'm wondering if that's the problem. If you replaced your cable, did you lube it? If so, what with and how? I assume a grease of some type, but getting it where it matters without messing up the cable with too much...the could be a balancing act. Any guidance or warnings appreciated. ~ Fish

 

[Ollie88]

Hi Jim, I had the exact same problem (speedo dancing, sometimes only engaged at 10-20mph+), I also ordered a new cable but that didn't make a difference so I ordered a new drive gear. I haven't received it yet as it's coming all the way from Japan but I will post here once I know more.

 

[-MaTTi-]

The drive and driven gear need match or you will not get proper tooth engagement and it will chew up the driven gear.

The drive gear allows few gears, for example my -81 BJ42: 33481-60060 N=6,MARK 6:15-17,N=6 (08/1980 - 10/1982)

So 15, 16 and 17 teeth driven gears will work.

 

[jimfischhp]

Hi Jim, I had the exact same problem (speedo dancing, sometimes only engaged at 10-20mph+), I also ordered a new cable but that didn't make a difference so I ordered a new drive gear. I haven't received it yet as it's coming all the way from Japan but I will post here once I know more.

Did you get that gear yet? Curious if it solved your problem. I pulled mine today and the gear looks good, but the cable was pretty rough. Unfortunately, the cable they sold me is too short since I have a chevy 350 + toyota 5 spd with an AA on it. I need something about 24" longer, so I'm working with Cruiser Corps to see if they'll exchange the shortie.

 

[pbgbottle]

Yes yours is worn out. Replace it

 

[Ollie88]

I got the new drive gear installed and it works perfectly fine again! No more dancing speedo!