Speedo / Tach / Gauges: Speedometer help needed

[packard352]

Hi,

Yesterday, I fitted a brand new speedometer cable to my 2R6-12 Pickup Truck, but was really disappointed to see the speedometer needle stay dead.

Now I'm left with either the adapter fitted to the 4-speed stick shift (no overdrive), or the speedometer itself as being faulty. I guess both could be bad too (worst case scenario).

So now I'm interested in what tests I can do to determine which unit is not working, what the remedy might be - easy or hard fix, or just buy a replacement adapter if it proves to be faulty.

I would also be interested in learning which would be the easiest unit to tackle first... and why?

I've attached a couple photos to help. The cable in the photos is the old cable.

It sure would be useful to know how fast, but more likely, how slow I am going, lol

Thanks for any and all suggestions,

Richard

[Skip Lackie]

You should be able to spin the back fitting of the speedo fast enough (CCW) with your fingers to see if the needle jumps off zero. And you can turn the cable by hand or with an electric drill to see if it is okay. The usual problem is that the cable is not meshing properly with the trans. Insert the cable correctly and see if you can turn the other end with your fingers. If it turns, then it's not meshing with the gear in the trans.

[packard352]

So here's the speedometer update. I reattached the old speedo cable into the back of the dash and with my wife sitting in the driver's seat, she was able to confirm the speedometer needle got up to 50 mph when I spun the other end of the cable vigorously with my fingers. The conclusion is there is an issue with the adapter without crawling under the truck. Looks like I'll be seeking a new adapter from one of esteemed vendors! Richard

[rockne10]

On one occasion I found the speedometer drive gear, which is slipped over the transmission output shaft, had stripped.
See if you can get a look at it through the hole the pinion fits in.

[packard352]

Got back under the truck late afternoon before the light closed in. I've taken a bunch of photos (x 14) and for me the most telling one of the bunch is the last one. Each photo has been cropped in the interests of reducing the photo file size. However, in the bad light this afternoon (we're getting leftover hurricanes coming across the Atlantic), I didn't see some of the chipped cogs.

Anyway, open to reading more views and suggested solutions, which will contacting some vendors I'm sure.

[packard352]

I've attached two photos from the previous post and the pic of the chipped cogs as they're all of the same internal drive unit and hopefully will complete the picture...

[PackardV8]

Usually there are numbers stamped on the adapter case which indicates the gear ratios.

I've got a couple around here if they can be found and if they're the correct gears, you could have them for shipping.

jack vines

[Chipmaker]

Before installing replacement gear, look in hole it came out of at the gear that drives it. Check for damage and any thing jammed between the teeth. Also probe the drive gear and make sure it is tight on shaft.

[packard352]

Chipmaker, I’m not so sure how easy that maybe to do.

I’ve got handbrake that clamps the half shaft, so there’s next to no eye sight room available. I do have a small camera with light that can be connected to my laptop, so is weather dependent.

But, I really hope it doesn’t mean the gearbox has to be dropped to be inspected.

[packard352]

The speedo gremlins are giving me a good fight for sure.

I was able to work from home today, which meant that lunch was a short break as I jacked the front of the truck up to get at the speedometer cable adapter, sleeve / shaft and pinion. In particular, I was interested to have another look at the pinion and with good sunshine, I was able to get some good shots off.

The race was back on this evening to get everything buttoned up again, so I could drive the truck back into the garage for the night.

However, before putting the adapter and all back on to the transmission, I tested the adapter. I hooked up my old speedo cable to the adapter, sleeve and pinion resting on some cardboard on the ground and was able to see the pinion spin around freely.

I therefore, deduce the adapter, sleeve and pinion are probably all okay... maybe even the old speedo cable was good too... and the cogs on the pinion don't looks so bad after all. But, someone may correct me on my deduction, which is fine.

Which now leaves me looking at the T-9, 4-speed gearbox ~ right?

As I've not been through this eye of the needle before, I'm still looking for any help (confirmation) that my sleuthing is correct, or not!

Thanks for reading and any further suggestion