speedometer reducer/gear question

[jcondo]

I got a 1977 K10 95% original. I bought it with the speedometer not working earlier this week. I am looking for info on where to buy the Gear and reducer. Every where I have looked so far is different then what I have.
Or if there are parts I can fix the reducer with, I can possibly weld the broken spot back into the Gear.
Thanks for any info, its greatly appreciated.

[geezer#99]

What tranny?
Do you have a speedo housing in the tranny?
These guys have gears and reducers.
https://transmissioncenter.net/?swoo...edometer-world

[jcondo]

Sorry I should have stated that its a full time 4wd. the speedometer hooks up to the transfer case.
it has the 400 engine and I'm pretty sure a TH700R tranny, just going off the few mins I was under the truck and seeing what the transmission pan looked like. the photo is of the transfer case number if that helps.
I will get accurate information Friday when I get back to the shop.

[S10Fan]

Originally Posted by geezer#99

What tranny?
Do you have a speedo housing in the tranny?
These guys have gears and reducers.
https://transmissioncenter.net/?swoo...edometer-world

Contact these guys, they've helped me with a couple speedometer gear/calibration issues.

[jcondo]

Update*
I was able to get the broken speedometer cable out of the gear today. Now to see if I can find a replacement for the cable part that comes out of the reducer and in to the gear itself.
I was gonna call the website you guys suggested, but we had a major storm with numerous houses and power lines damaged. A normal 8 hour day turned into a 12 hour day.

[jcondo]

Located another gear reduction part and took the good speedo shaft out of it and installed it into my correct gear reduction unit. Still not working, thinking my speedo cable or gauge is bad.
But I got called into work so haven’t been able to go any farther with it yet.

[hatzie]

Full time 4x4 is the NP203 transfer case. If the transmission is original it's either a TH350 or TH400. The TH700R4 is a 4 speed auto that was first available from the early 80's on.

You can buy that metal driven gear for the NP203. They aren't pricey. Yours looks like it's been recovered from the bottom of the ocean.
Check the plastic helical drive gear on the transfer case output shaft to make sure it's not stripped.

Do you have cruise control?
The break in the end of the driven gear makes me think you may have a very tight or seized speedo cable or a seized or siezing up Cruisemaster transducer... or the gears in the ratio adapter are worn and bind up.

[jcondo]

Originally Posted by hatzie

Full time 4x4 is the NP203 transfer case. If the transmission is original it's either a TH350 or TH400. The TH700R4 is a 4 speed auto that was first available from the early 80's on.

You can buy that metal driven gear for the NP203. They aren't pricey. Yours looks like it's been recovered from the bottom of the ocean.
Check the plastic helical drive gear on the transfer case output shaft to make sure it's not stripped.

Do you have cruise control?
The break in the end of the driven gear makes me think you may have a very tight or seized speedo cable or a seized or siezing up Cruisemaster transducer... or the gears in the ratio adapter are worn and bind up.

Thanks for the reply, I was mistaken when I said the tranny was a TH700R, its actually a TH350. everything on the truck is original so far except the transmission pan, they put an after market air cooled pan on it.
Yes the gear looks bad, its been out of the transfer case for many years it seems. I donot have cruise control option. I am planning on changing the speedo cable, also on replacing all ujoints, so ill take the tail shaft housing off the transfer case and look a the gears when I have the drive shaft out.

[hatzie]

I usually replace the driveshaft bushing and seal in the end of the tailshaft housing while I have em off. It goes without saying theere's probably a bunch of crud sitting on top that you don't want falling inside the transfer case. The drive gear is not difficult to replace if it's knackered. Surprising the driven gear looks like that if it was installed...

BTW the NP 203 takes 30W non detergent motor oil. Lots of folks fill em with ATF or gear oil but the original fill was 30W non detergent. The older New Process cases are odd ducks. My NP201 in the 67 Dodge takes 50W non detergent motor oil. I run 75W90 Synthetic in the NP205 in the 72 F250... same as the axles in everything I own that has axles.