Speedometer Question

[kwmech]

Originally Posted by 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.

DO NOT DO THAT!!, Unless you really know what you are doing, he could lose the needles at the rear of the support, AND if the shaft comes out far enough by accident he could lose the pocket bearings in the end of the shaft into the case. Pull the aluminum seal housing off (5 bolts). Get a couple of screw drivers and gently work the output bearing out of the cast housing. Under that will be the speedo gear.


Depending on the year of this thing, more than like though you probably have a steel gear in there as well. At this point I would remove a couple of phillips screws in the small adapter and take that reducer apart, you'll probably find a gear with a tooth or 2 missing

[randy500]

Originally Posted by kwmech

DO NOT DO THAT!!, Unless you really know what you are doing, he could lose the needles at the rear of the support, AND if the shaft comes out far enough by accident he could lose the pocket bearings in the end of the shaft into the case. Pull the aluminum seal housing off (5 bolts). Get a couple of screw drivers and gently work the output bearing out of the cast housing. Under that will be the speedo gear.


Depending on the year of this thing, more than like though you probably have a steel gear in there as well. At this point I would remove a couple of phillips screws in the small adapter and take that reducer apart, you'll probably find a gear with a tooth or 2 missing

Great catch, haven't taken one apart in a very long time.
http://67-72chevytrucks.com/vboard/a...1&d=1124774942

Here is an exploded view which appears applicable, doesn't appear to be room to place the speedo gear in the wrong position like on a manual trans.

[K10Kent]

Originally Posted by kwmech

DO NOT DO THAT!!, Unless you really know what you are doing, he could lose the needles at the rear of the support, AND if the shaft comes out far enough by accident he could lose the pocket bearings in the end of the shaft into the case. Pull the aluminum seal housing off (5 bolts). Get a couple of screw drivers and gently work the output bearing out of the cast housing. Under that will be the speedo gear.


Depending on the year of this thing, more than like though you probably have a steel gear in there as well. At this point I would remove a couple of phillips screws in the small adapter and take that reducer apart, you'll probably find a gear with a tooth or 2 missing

I'm thinking the gear ratio is ok because I put the cable directly into the transfer case and it still sat at 0 mph. When I get home tonight, I'll see if the metal drive gear is centered in the hole. If not, I'll take aluminum housing off and see if I can slide it back with a gear puller or something.

[K10Kent]

I got the drive shaft off but I don't have a 1 3/8" socket that allows me to get the aluminum housing off. So I'll get that tomorrow and try again. I did put a screwdriver on the drive gear and it's not loose at all. When I put my speedo driven gear in, I can turn the driven gear freely so they are not meshing for whatever reason.

[kwmech]

1-5/16'' socket, and judging by the new picture, you'll have to switch places with the spacer

[K10Kent]

Originally Posted by kwmech

1-5/16'' socket

You just saved me about an hour or more out of my day!

[randy500]

The new picture does show the gear is not center d in the hole. Great idea on inserting the gear and housing to find it's not meshing! The gear is very soft so be careful with it.
Look carefully at the cutaway view I sent, very easy to have that shaft come out and loose the roller bearings at the front of that shaft...

[randy500]

Looks like a spacer is missing in front of speedo gear, here is a pic
https://www.google.com/search?q=np20...stPSxCTZD30LM:

[K10Kent]

I'm hoping kwmech is right about the placement of the spacer and drive gear being swapped. We will see tonight!

[kwmech]

Originally Posted by K10Kent

I'm hoping kwmech is right about the placement of the spacer and drive gear being swapped. We will see tonight!

If the spacer wasn't there, the gear would spin freely on the shaft. Tightening down the driveshaft yoke is what locks everything down on the shaft

[K10Kent]

Got everything out but the drive gear. I'll have to get a gear puller tomorrow. I'm a little worried about putting too much force on it with a screwdriver.

[kwmech]

Gear puller not needed. Go through the speedo hole and give it a little nudge with a flat blade screw driver, it should slip off like the spacer

[K10Kent]

I've given it more than a nudge. I've dang near broke a screwdriver. I also almost messed up the threads on the speedo gear hole from prying against it. I got a gear puller and it's too tight to fit well but I've managed to put some pretty good force on the gear from the other side. I'm at a loss here.

[kwmech]

Can you see the line where the gear stops and the shaft is through the speedo hole?

[K10Kent]

No the gear is too far forward.

[randy500]

I think I would try some heat from a propane torch right on the gear, it should heat up pretty fast and expand before the shaft does, then it would slide off.
Since the gear is slip fit it must be stuck by dried grease/oil or hydrostatic pressure of the grease/oil, the heat would help break that bond.

[kwmech]

The heat should help, gear still shouldn't be jammed on there that tight though.....unless there is a sharp edge on the gear and it is stuck on the small radius of the shaft

[K10Kent]

I went out and bought a little propane torch and got the heat on it. I heated, I pried, I screamed at it......not budging. I decided I had to do something else so I took off the cast iron housing to get better access to the drive gear. I'm sure you guys already know that the whole shaft comes out when you do that. Then all the needle bearing pieces come out with it. I didn't lose any of them but I'm going to have to figure out how to get all of this back together. I may have made a mistake here. The worst part of the story.... even with the shaft out, I can't get that $$&()"@ drive gear off the shaft!!

[kwmech]

Looks like you had to pound the shaft out of the cast iron housing with the support bearing remaining on the shaft. The only thing at this point I can think of is sliding the support bearing back so you can see the line where the gear and the shaft come together and place a sharp chisel at that point and give it a rap.



I just looked at a 205 I have apart here and there is no reason why that gear should be jammed on the shaft like you are experiencing. The one here floats on the shaft every which way. AND the shaft where the gear is seated is partially undercut, so there should be no binding there.

Once this is resolved, the hardest part you should have is getting the pocket bearings back where they belong with some sticky grease AND BEHIND the washer

[kwmech]

So, what happened with this? get it squared away?

[K10Kent]

Well I finally got the drive gear off and then I got pulled away on other things that couldn't wait. I'm going to get back at it tonight. I hope I can get it all back together this evening. Is getting those roller pieces back in going to be a huge pain?

[randy500]

Use heavy grease to hold the needle bearings in place.

[demian5]

Originally Posted by 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.

I bet your speedo cable wasn't going into the drives far enough.

[kwmech]

Originally Posted by randy500

Use heavy grease to hold the needle bearings in place.

Exactly, thick grease and a small finger. The needles should go under the washer.

[K10Kent]

I put it all back together and got the position of the drive gear and the spacer switched. Took it out for a drive and it works! All gauges working now! Thanks everyone for the help on this.