Author Topic: NP 203 rear yoke nut  (Read 9229 times)

Offline berserk

  • Newbie
  • Posts: 98
NP 203 rear yoke nut
« on: May 29, 2024, 04:01:12 am »
I have an NP203 transfer case and Just replaced a bearing that required me to take off the rear yoke. Now I'm ready to reinstall everything I have found out that the yoke nut is supposed to be a one-time use locking nut. So in an effort to do everything correctly I have been looking for a replacement and cannot find this thing anywhere!!!

I have looked on all the parts websites that I know, forum searches, parts houses, I called local four-wheel drive shops etc. I can find a pinion nut anywhere I look but cannot find either the part or part number for an NP203 rear output yoke nut. Anybody run into this before? At this point I'm probably going to just torque it down with red loctite and call it good. But as I age I try to do things less redneck and more by the book. So I'd really like to get a fresh locking nut for the transfer case yoke. Please let me know a source for the part or a success story reusing the OG nut 😂
76 Chevy k10 350/th350/203 part time. Vortec head 350 Dana 60 w/Detroit, 14 bolt Tru Trac, 33" Micky T. Mudders.

Offline Mr Diesel

  • Frequent Member
  • **
  • Posts: 357
  • Aaron
Re: NP 203 rear yoke nut
« Reply #1 on: May 29, 2024, 07:21:19 am »
I'm not familiar with that particular locknut, but locknuts in general are either built with tiny metal protrusions into the threads or a plastic insert. Both accomplish the same idea: create enough extra friction that the nut doesn't vibrate loose. In theory they are one-time use items since the process of tightening them down causes then to "set" in place on the threads, but I have had good luck reusing them anyway.

I would NOT red lock tight it. MAYBE blue, but even that probably not necessary and just gonna make it harder for the next guy to take it apart.
1976 C20 Crewcab, 6.2L/SM465
1982 K30 Crewcab , 427TD/TH400
1983 C30, 6.2L/TH400
1983 K30 Crewcab 454/700R4
1986 K10 350/400. 1989 K30 cab/chassis 454/SM465

Offline berserk

  • Newbie
  • Posts: 98
Re: NP 203 rear yoke nut
« Reply #2 on: May 29, 2024, 10:33:23 am »
Yes it's a all metal flanged locking nut that takes a 1 5/16 socket.


Trucks been in the family for 32 years and won't have another owner. I have more time, money and memories in this truck than someone could afford. But I will take your advice into consideration, thanks!!

Best outcome would be to find a new one, I think I may talk to a few transmission shops that deal with T cases to see what they use as well as see if I get a part number on this forum.
76 Chevy k10 350/th350/203 part time. Vortec head 350 Dana 60 w/Detroit, 14 bolt Tru Trac, 33" Micky T. Mudders.

Offline Mike81K10

  • Junior Member
  • ***
  • Posts: 996
Re: NP 203 rear yoke nut
« Reply #3 on: May 29, 2024, 04:16:02 pm »
It is too bad they don't have a hole to safety wire it in place.
"Tell me and I forget. Teach me and I remember. Involve me and I learn." -Benjamin Franklin

Online bd

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6592
Re: NP 203 rear yoke nut
« Reply #4 on: May 29, 2024, 05:18:39 pm »
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline berserk

  • Newbie
  • Posts: 98
Re: NP 203 rear yoke nut
« Reply #5 on: May 29, 2024, 10:27:31 pm »
Wow!! I didn't even think about eBay 😂 I used the part number and found another ad with the specs out of a service manual and confirmed it's the right part.


It looks like the part you linked is still available, I have never ordered anything off eBay. Anyone know the safest payment method or tips when purchasing?
76 Chevy k10 350/th350/203 part time. Vortec head 350 Dana 60 w/Detroit, 14 bolt Tru Trac, 33" Micky T. Mudders.

Offline JohnnyPopper

  • Senior Member
  • ****
  • Posts: 2713
  • Old Goof
Re: NP 203 rear yoke nut
« Reply #6 on: May 30, 2024, 10:43:49 pm »
bd never fails to surprise...

Better get it, I have the same Xfer case... 8)
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline berserk

  • Newbie
  • Posts: 98
Re: NP 203 rear yoke nut
« Reply #7 on: May 31, 2024, 12:27:04 pm »
😂 I tested my old one by hand threading it on and the "locking" portion of the threads showed no resistance. I was able to run the nut snug against the spacer by hand, that shows me it's no good.


I ordered the nut from the eBay ad linked, thanks for the help guys!

Edit: Just got the part from DC truck parts on eBay, the shipping was quick, he provided a tracking number and the part was packaged good!
« Last Edit: June 06, 2024, 08:37:56 am by berserk »
76 Chevy k10 350/th350/203 part time. Vortec head 350 Dana 60 w/Detroit, 14 bolt Tru Trac, 33" Micky T. Mudders.