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TR2/3/3A Speedometer question

Because they are mechanically separate counters. They're driven by the same cable, of course,but most of the mechanics are not common to both counters.
 
I have, but it's tricky. I would consider doing it again if it didn't involve disassembly of the odometer counter itself. The rest of the stuff is much easier to deal with.

That said, if only one counter is not working, something is probably worn or broken, and you won't have spare parts. I would either find a replacement speedometer or send it to a specialist; there are a lot of them and, from what I've seen, most are not unreasonably expensive.
 
I agree about taking the counters apart. Sometimes they get sticky and if you click them a little without taking apart they can become unstuck.
 
I agree about taking the counters apart. Sometimes they get sticky and if you click them a little without taking apart they can become unstuck.
Replying to myself, must be past the edit window. I didn't explain that very well. Once you have the cover off you can access the counters. As I recall you can move the separate digit rollers by hand or with a small screwdriver. There is a metal piece that extends out from the digit roller that facilitates this.
image-4.png
 
Replying to myself, must be past the edit window. I didn't explain that very well. Once you have the cover off you can access the counters. As I recall you can move the separate digit rollers by hand or with a small screwdriver. There is a metal piece that extends out from the digit roller that facilitates this.
View attachment 105474
So it is possible that the rollers may be just stuck and they can be freed up. Should a person use some sort of light lubricant to help gets things moving? This might be worth a try before sending the unit out to a shop?
 
In my opinion worth a shot, I use this stuff, sparingly.

Have a look at this:


You have probably lost some teeth from one of the plastic gears. You can rob a gear from a scrap speedometer but there are several different types, depending upon the speedometer gearing. If you find any Smiths speedometer with the same turns per mile (the three or four digit number after the SNxxxx/xx number) it will have the same gear as your speedo.
 
TR3 should have metal teeth, unless it has been mixed and matched with later heads.

The normal failure is gear lube from the tranny works its way up the cable into the speedo head. Then, over many years it becomes a sticky solid that jams up the Odometer mechanism. The odometers are very fidgety, with many small parts...only a job if you are very organized and a patient worker. But, with care you might be able to clean the mechanism of old lubricant and get it turning again without dis-assembly.
 
TR3 should have metal teeth, unless it has been mixed and matched with later heads.

The normal failure is gear lube from the tranny works its way up the cable into the speedo head. Then, over many years it becomes a sticky solid that jams up the Odometer mechanism. The odometers are very fidgety, with many small parts...only a job if you are very organized and a patient worker. But, with care you might be able to clean the mechanism of old lubricant and get it turning again without dis-assembly.
That's good to know that it is doable. A good winter project.(y)
 
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