Speedometer Stopped Working As Mileage Rolled Over

The other day while driving, I was watching the speedo gauge hit a milestone. 76000 miles. As the mileage started rolling over from 75999, the speedo needle froze at 30mph. At the next stop light I tapped on it (cause that AlwAYs WorKs) and nothing. When I started again, I got up to 30mph (i assume) and the needle climbed a bit and quickly looped all the way around clockwise and came to rest between the temp gauge and 0 mph.

The Odometer still works and now reads another 5 or so miles.

If I reverse, The needle moves a bit but then If I go forward it loops again.

Any Ideas?

This is not the original speedo. It was installed a few owners ago and they somehow matched the odometer when doing so.

 

Pull the cable out the back and see if there is evidence of transmission gear oil. Sometimes the spiral of the cable pulls gear oil up and gums up the speedo mechanism.
-Donny

 

What Donny sez or a small critter (wasp etc) built a nest in the speed cup.

 

Just pulled the speedo. Heres what I'm seeing initially. Tell me if it looks normal or if anything is glaring>>>

The threads on the back looked as if there were ground brass. no trace of any wet lubrication. Not sure what they're lubed with though.
The cable also didn't seem wet on either end besides a bit of tranny fluid on the low end tip.

I also made a video of me testing the spin with my drill.

Link Here:

 

Definitely there’s binding at the head of the speedometer itself. In your pic you see shavings, those shavings I believe are the culprit. Clean all around the base of the speedo and spray with WD-40 or the like. See if that corrects it.

 

On the earlier speedos, there was a tiny lubrication port where the rear bearing enters at the back of the head. Can't see from your pictures if you have one.

I'm wondering if the shavings are a result, not a cause. But not good either way.

Did you pull the cable core out to inspect it? It should have a light amount of lube. And no wild hairs - if pulled up an inch or two, it should turn freely in either direction.

Some speedo issues can be caused by a cable core being cut too long, and putting pressure against the speedo bearing. If driving with the top nut slightly loose improves the speedo behavior, that may be a clue.

 

I havent pulled the cable out yet but i will! What kind of lube should I use? Lithium grease? Silicone spray? wd40?

Here are some more pics of the back.

 

A smear of grease or oil on the core. Graphite lube back in the day. You don't want excess oil entering the head.

(BTW - WD40 is not a good lubricant in any real sense.)

It appears your speedo has a vestigal boss on the casting but the bearing lube port was eliminated. I'd see if you can get a (small) drop of light oil into the bearing.

 

Could that be achieved by dripping a drop of oil into the hole that the cable goes into from the outside? Or are you talking about taking the case apart and dropping oil on somewhere internal?
I have some light bike chain oil. maybe that could work? I def dont want to overdo it haha.

 

I'ld think sewing machine oil would be ideal. Bike chain lube may actually be wax or silicone based.

 

Some light lube may help though it looks like some wear or binding is going on internally. I say this because the needle went too far when you drove it.
I took mine apart to clean out bugs and lube it. Set back to -0-. This may or may not be something you want to try. If all else fails, take it a speedo repair shop.

 

On the speedo core you can use Vaseline. As stated by Pete, it looks like the core is too long and has put too much pressure on the rear bearing. The flat shoulder on the core tip should ride in the bottom of the coupling that screws to the speedo.

 

That happened to my dad on a UPS truck as it rolled to 1,000,000 miles. He was let down because he wanted to see it.

 

Remind me to never buy a 'low-milage' UPS truck.

 

Lol!

 

I went ahead and cut 1/4” off the tip of the core to help with it smashing up against the cup.
I also coated the core with Vaseline (except for the top 6” or so) and wiped off the excess before reinstalling.

in the speedo assy, I was able to take off the face and check out the guts a bit. There was some dust in there but nothing too grimey. I blew out as much as I could, and swabbed out some of the bigger stuff with some Q-tips. Added a drop of gun oil into the bearing and just the tiniest tiniest bit dabbed on points of contact that seemed worthy.

Didn’t really want to shoot WD-40 around anywhere in there, especially because it didn’t seem dirty enough. Everything seems like it was moving as it should before I put it back together.

The gas tank is still out of the jeep currently (another project) so I can’t drive it around the block to test for a couple days but I could twist the end of the core with my fingers at the transfer case and the needle jumped so… Fingers crossed.

will update once I take a test drive.

btw…. I called the only speedometer repair shop for 20 miles and they quoted me $525-$1000. This was after I told them a brand new unit goes for $125

That’s LA for you LOL.

 

In the modern world, no reason to be limited by geographical area.

 

For sure. Hopefully it won't come to outsourcing.

 

well did you try the drill again . just don't go pass 9

 

0h Yeah......My 2 cents is : throw the w2 -4 0 away. It's mostly made with water . Silicone or Tri-Flow only. Again, a wee bit of the light machine oil is all those gauges ever need.