Dana 300 Speedometer gear

[BusaDave9]

Are you sure the speedo gear rotates the opposite direction on the Dana 300 ? That would mean the speedo cable rotates the opposite direction and I know you can swap out TCases without having to swap out the Speedometer. Just because the cable comes out the other side doesn't necessarily mean it is rotating the other way.
For example lets say you remove the tail housing and then rotate it 180°. Of course the bolt holes will no longer line up but if they did then the speedometer gear and cable will still rotate the same direction.

 

[LASTCJ786]

I'm thinking the Scout 300 taht it came out of had 3:54 gears and 31" tires and it has 13 teeth . So If i'm running 3:73's with 33" tires then I think I need a 15 tooth gear. sound right?

 

[BusaDave9]

I'm thinking the Scout 300 taht it came out of had 3:54 gears and 31" tires and it has 13 teeth . So If i'm running 3:73's with 33" tires then I think I need a 15 tooth gear. sound right?

since you are getting bigger tires (33" instead of 31") you should also get lower gears (you are - .3.73 instead of 3.52) the speedometer shouldn't be too far off even with the same speedometer gear.
I checked the proportions of axle gears to tire size and it looks like even without changing the speedometer gear your speedometer will only show 1% slower speeds after this swap. I would go ahead and make the change, and then check your speedometer. It is easiest to test the odometer by comparing it to the mile markers. Please follow up and let me know how far off I am but I bet you don't even want to change the speedometer gear. That 1% won't be noticeable. You would have to be going 100 mph before your speedometer is off by 1 mph.
Since you now have 13 teeth on your speedometer gear going to 12 teeth will make a 7.7% change in your speedometer. That's way too much.
Check you odometer before you make any changes. It may be off already.

 

[LASTCJ786]

I'm off by about 5 milies a hour.

 

[BusaDave9]

At what speed were you going when it was off by 5 mph. I need to know how far off your speedometer is off as a percentage. If you were going 55 but your speedometer said 50 then it is off 10%.

 

[LASTCJ786]

It just seems like it's off about 5 miles ahour at all speeds.
When I first got my 86 Jeep (90) I had 2:73 gears junk! I had 3:73's put in
and the speedo was off read to fast. That was with a T-176 and Jeep 300.
You can get the speedo gear for a 86 Dana 300 .
Now I'm running a Jeep T-18 and Scout Dana 300 with the 3:73 gears.

 

[BusaDave9]

Is your speedometer too fast or too slow?
Check it with your odometer. On the highway pull over next to a mile marker. Write down the mile marker and write down the odometer reading. Drive 10 miles and pull over next to the mile marker 10 miles past the place you last stopped. Write down both numbers again. Let me know all 4 numbers or figure out what percentage it is off.
Those speedometer gears with less than 20 teeth are hard to find. You might want to see if you can find a seller first. I am looking for one with 17 teeth and haven't found one yet.
I have tried:
Nevada Speedometer 1-775-358-7422,
and North Hollywood speedometer 818-761-5136
and PATC 1-888-201-2066
and google and ebay.

 

[LASTCJ786]

I've got a line on one I hope. I'll let you know. My speedo is reading to slow. I know I'm going faster then my speedo says.

 

[LASTCJ786]

I have called my conatct for 2 weeks everyday. Says he has some but has not told me the tooth count yet. Had it on the Highway Saturday had the speedometer at 55 and the GPS said 65.

 

[BusaDave9]

First let me make sure I have my facts strait: you have a speedometer gear that has 13 teeth. Your speedometer reads 15.38% too slow (when you are driving 65mph your speedometer reads 55mph)
If that is correct then you need a speedometer gear with 11 teeth. The smaller gear will cause your speedometer to run faster and should then be much more accurate.
Let me know who your supplier is. I have been looking for a 17 tooth gear for my Dana 20 . People on this site have given me recommendations to find the gear but nothing has panned out.

 

[hagar]

13 is the lowest tooth count made for Dana 20 that I could reference.

 

[tim843]

[/ATTACH]

Trying to get the speedometer working on my 78 Jeep CJ5 V8 AMC 304 . A new cable didnt work. However, I can spin the speedo cable with my fingers and the speedo needle bounces up quickly as it should and odometer changes. When its hooked up needle doesnt move and it takes about 3 miles to change odometer 1/10 a mile. Attached a pic of the speedometer driven gear: it has 15 teeth.
I can stick my finger in the rear bearing cap and feel a lose gear sliding up and down what I think is the rear output shaft (I think this is the speedometer drive gear).
Can someone identify my Tcase by the pics? The tag reads 300596-125 on top, 5357020 on bottom. The case is stamped C18-15-24-8.
On the Rear bearing cap is stamped C18-19-44

 

[BusaDave9]

I can't see your image but unless it has been swapped out your jeep came with a Dana 20 Transfer Case .
Here is what the tcase output looks like:

Part 18.240-1 is the gear you are talking about that may not be rotating with the output shaft.

 

[hagar]

most likely your drive gear is bad. Most were made one piece metal design; some were made with an aluminum sleeve that had a nylon gear over that; what would happen is thru age and heat the nylon gear becomes loose on the aluminum sleeve; the sleeve turns but the nylon gear does not; a classic sign of this is the speedo works when cold or first driven about the first 10-15 miles; then the speedo gradually slows down till it stops working.
and it looks like a Dana 20 as previously mentioned.

 

[LASTCJ786]

Border Parts 1800-5330171 ask for John

 

[tim843]

Thanks for the info. How do I fix? Can these parts be replaced without dropping the Tcase? Do I drop the rear drive shaft and get to the bad parts? Thanks,
Tim

 

[BusaDave9]

The tail housing and output shaft can be removed without removing the TCase. There are 5 bolts holding it on. The speedometer drive gear in in the middle of this assembly. To take it apart you need to remove the large nut holding on the U joint yoke. That nut is big and takes a lot of leverage to remove. I would remove it before removing the rest of the tail housing. Here's how I would do it: Drain the oil from the TCase. Remove the rear drive shaft. Put the jeep in 4WD low. Put the tranny in reverse. Remove the nut holding on the U joint yoke. Remove the five bolts holding on the tail housing. Once that is removed you can repair the speedometer gears.