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NP208c

Holey76 - Square Nut

Holey76 - Square Nut

1/2 ton status
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Hi guys.
I cracked open an NP208c that i just bought, and these fell out immediately. I can't see them in the parts diagram. Anybody know what they are and where they go ?

20250730_092221.jpg

20250730_092209.jpg
 
Holey76 said:
Hi guys.
I cracked open an NP208c that i just bought, and these fell out immediately. I can't see them in the parts diagram. Anybody know what they are and where they go ?

View attachment 509381

View attachment 509382
Click to expand...
It's been a while since I opened one myself but they remind me of keys to go in between the two case halves, to secure them together.
If you don't get a response soon I will be taking one apart in the coming days
 
imiceman44 said:
It's been a while since I opened one myself but they remind me of keys to go in between the two case halves, to secure them together.
If you don't get a response soon I will be taking one apart in the coming days
Click to expand...
Thank you. I see, (on the curved side) what looks like wear marks ?
Can you see em in the pic ?
 
imiceman44 said:
It's been a while since I opened one myself but they remind me of keys to go in between the two case halves, to secure them together.
If you don't get a response soon I will be taking one apart in the coming days
Click to expand...
Thank you. I see, (on the curved side) what looks like wear marks ?
Can you see em in the pic
Holey76 said:
Thank you. I see, (on the curved side) what looks like wear marks ?
Can you see em in the pic ?
Click to expand...
They wouldn't be some type of chain tensioner?
 
Holey76 said:
Thank you. I see, (on the curved side) what looks like wear marks ?
Can you see em in the pic

They wouldn't be some type of chain tensioner?
Click to expand...
The wear marks look like the shifter rail is ramping up on it?
I should have time to take one apart next Monday or Tuesday if no one else chimes in
 
It's a "syncro key". They're part of assembly 23 below. Those snap rings are kind of like springs that hold them out, but let them push in for the collar to go over them. Those may be broken or missing. I'm not sure what the symptom would be, other than it wouldn't quite lock in place.
1753902136321.png
 
Last edited:
imiceman44 said:
The wear marks look like the shifter rail is ramping up on it?
I should have time to take one apart next Monday or Tuesday if no one else chimes in
Click to expand...
I've tried to fit them into and around the selector cam but no bueno.
I'll keep trying, and i appreciate your looking into yours next week , thank you.
 
Blue85 said:
It's a "syncro key". They're part of assembly 23 below. Those snap rings are kind of like springs that hold them out, but let them push in for the collar to go over them. Those may be broken or missing. I'm not sure what the symptom would be, other than it wouldn't quite lock in place.
View attachment 509386
Click to expand...
Is the box (23) the planetary and planetary carrier ?
Before i cracked it open, i noticed the main shaft/input shaft was traveling almost 1.5". Now i think I see why. The magnet had more shrapnel than a war zone. I'll go have a look and update this. But I'd bet your right on the broken ring, which would explain why the syncro keys are rattling around.
 
#25 is the planetary set (ring/planets). I don't know the name of #23, but it's the range selection. That is, whether the main shaft turns at the speed of the input (sun) or if it receives multiplication from the gears.
EDIT, I was wrong on that. Seeing it right by the planetaries threw me off, I guess. It is actually the mode selection. That is, in the drive to the chain engaged or freewheeling. There would be little point having a synchro on the range selection.
 
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Those are indeed the syncro keys, or syncro struts as another diagram refers to them. The planetary was locked to the planetary carrier and when I disassembled, i discoveed chunks of metal locking the gears together. Now i see there are supposed to be 3 syncro keys/struts, but i only found 2. The magnet was loaded with needle bearings and race material. What a basket case. :frown
 
Holey76 said:
Those are indeed the syncro keys, or syncro struts as another diagram refers to them. The planetary was locked to the planetary carrier and when I disassembled, i discoveed chunks of metal locking the gears together. Now i see there are supposed to be 3 syncro keys/struts, but i only found 2. The magnet was loaded with needle bearings and race material. What a basket case. :frown
Click to expand...
Thank you Blue85 for identifying those parts !!:)
 
I was just looking st the mainshaft pic i took, and noticed another needle bearing next to the selector spring. I'm wondering if i should even bother to go through the mainshaft. What would you need for a complete mainshaft ?
 
Holey76 said:
I was just looking st the mainshaft pic i took, and noticed another needle bearing next to the selector spring. I'm wondering if i should even bother to go through the mainshaft. What would you need for a complete mainshaft ?
Click to expand...
I will see how much it is for shipping something this long first.
 
Honestly 208’s are a dime a dozen. I’d find a better one that hasnt had metal run through it.
 
Fastereddie said:
Honestly 208’s are a dime a dozen. I’d find a better one that hasnt had metal run through it.
Click to expand...
If someone is going to blazer bash I could send the whole thing but,I don't know the conditions since they came off trucks I parted.
I personally would go through any tcase I put in my vehicle
 
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