Speedometer Question

[K10Kent]

My speedometer is not working at all. Here's what I've done so far: I took off the cable at the gear on the transmission and turned it with a drill. It moves the needle. So I think it's probably my gear ratio piece so I hook it u to my cable and turn it with a drill. Still works. I look at the square cable and it's not rounded off so I guess my transmission is not turning the cable. What would cause that??

[randy500]

Stripped speedo gear could cause it, pull the gear housing out and look at the gear. Could also me damaged gear on output shaft of trans.
That ratio adapter makes a nice handle to pull the round speedo gear housing

[K10Kent]

You're saying to take this out of my transmission and take a look? Just want to make sure. I'm guessing I may have some fluid come out with it?

[K10Kent]

See pic

[randy500]

Originally Posted by K10Kent

See pic

Yes inside of that is a plastic gear which is driven by a gear on the output shaft. When you remove it you can look inside at the gear on he output shaft, that gear is plastic on auto transmissions and usually metal on manuals. I see yours is 4wd and on the transfer case, I haven't personally removed one like that but it's the same general set up.

[randy500]

The metal piece in the center is the speedo driven gear and it appears to be metal. The ratio adapter in he previous picture does have a 1.5 inch long piece that is removable rihgt? Post a picture of the inside of the ratio adapter from the end with the hex nut

[randy500]

You willl loose oil if that speedo gear is lower than the fill plug, if not lower then you shouldn't loose much oil.

[K10Kent]

The gear ratio does have a square metal shaft. I suppose it's removable but I did not try.

When I get home tonight, I will take out the speedo gear in the transmission. I'm going to have to buy a socket to fit that: I don't have anything big enough. Thanks for the help with this. I'll let you know what I find out.

[davepl]

I've got a weirder one where turning it with a drill moves the speedo and if you run the wheels, you can see the end turning, but plug it all together and it doesn't work.

I think my inner cable is too short perhaps, so throwing that out there as a possibility.

[K10Kent]

When you say 'you see the end turning' , do you mean the end at the speedo gauge? I wonder if it might be rounded enough to be slipping, but when you attach a drill you don't have that problem.

[Andy4639]

Originally Posted by K10Kent

See pic

There should be a plastic gear inside the trans for the cable to slide into. I don't see it in your picture.

[K10Kent]

This pic helps a lot. Looks like I can just pull that out instead of getting a socket to fit it. I see what was meant by using the gear ratio as a handle to pull it out. Thanks! I check this tonight.

[randy500]

Originally Posted by K10Kent

This pic helps a lot. Looks like I can just pull that out instead of getting a socket to fit it. I see what was meant by using the gear ratio as a handle to pull it out. Thanks! I check this tonight.

I'm not an expert on 4wd but from your picture I think your Speedo gear adapter does unscrew, your gear will be much smaller but similar

[randy500]

Here is a picture of np 205 speedo gear housing
https://www.google.com/search?q=Np20...UwirfZzvIfIFM:

[Andy4639]

Originally Posted by randy500

Here is a picture of np 205 speedo gear housing
https://www.google.com/search?q=Np20...UwirfZzvIfIFM:

That is correct. My picture was a generic picture of a 2 wheel drive.
Either way though it looks like your gear is missing.

[K10Kent]

I got the socket and pulled it out last night. You guys were right, it's a metal gear. It looks to be in pretty good shape. I put it on the cable to check it all together and turned the little gear by hand and everything was tight and seemed to work fine.
I tried to take a pic inside the hole (pic 2). It's hard to see in there but it doesn't look stripped. So I put the driven gear back in and I can tell it's connected to the drive gear. The driven gear wasn't loose or turning freely. So I went for a test drive and at first I had a couple of bobbles on the speedometer, but then it went back to zero and stayed there. I'm thinking that maybe the drive gear needs a keeper pin, and maybe it's slipping on the shaft. I should have tried to turn it last night to see if it moves. I guess I'll try that tonight but it looks like I'm going to have to open it up.

[davepl]

Originally Posted by K10Kent

When you say 'you see the end turning' , do you mean the end at the speedo gauge? I wonder if it might be rounded enough to be slipping, but when you attach a drill you don't have that problem.

That's a possibility, I don't recall from memory, but will check it! Thanks!

[randy500]

I think the Speedo cable could have the tip broken off and not engaging the dapter or the ratio adapter could be bad. Test Speedo operation by removing ratio adapter and connecting cable directly to transfer case. That will isolate the ratio adapter.

[K10Kent]

I connected the speedo cable directly (without the ratio adapter). Still not working. I guess I have to open it up and see what's going on.

[RodnRudy]

From the last pic you posted it looks to me like the drive gear on the tail shaft might be too far forward. Could it have slipped forward on the shaft? Try prying the gear rearward to see if it will move on the shaft.

[K10Kent]

I'll give it a try tonight. Thanks for the tip

[randy500]

It does appear the speedo gear inside the transfer case is too far forward, it should be centered in the hole, picture could be skewed, verify it is centered. You won't be able to move it without a press. You can remove the tailshaft and move it with a gear puller though, or a tube and hammer to drive it in further if needed. Usually when pressing those on you center the gear on the raised portion of the shaft. Automatics and later ,Odell trans have a plastic gear held on with a spring clip under the gear, old manual trans are pressed on

[K10Kent]

When I bought the truck, I remember the seller told me he had just rebuilt the transfer case. I bet it's likely that he didn't get the drive gear pressed on far enough. That's a lot of help. I haven't ever taken one apart but I'll see what I can get done on it.

[randy500]

Nothing will fall apart or fall out by taking off the output housing. Remove the driveshaft yoke, not sure how tight those are. then just take off the 6 bolts or so holding the housing onto the transfer case, shouldn't even loose much oil. Check if gear is centered in hole before doing anything though.

[randy500]

And no need to take the aluminum tailshaft piece off first, just remove the cast iron tailshaft at the transfer case main body with the aluminum one attached.