Transfer Case NP-203 issues

[Is that Normal]

Hey guys,
79 k10, Having issues with t. case where after 15-20 min of driving at 55 mph+ it pumps gear oil out of the breather tube.
I just got this in and it already had the full time 4X - conversion done where it's not full time now and i put locking hubs in. I put an elbow off the fill hole to be able to run more oil in it as everyone says you need to when that conversion is done, however it's still doing this even after spitting out over 1 qt +. I've even drained it, put less than book calls for and still same issue. I am not having tranny seal issue as I'm not losing or gaining any tranny fluid. Also put in new seals previous to installing t.case.

Second issue: I cannot get it to go into Low lock. It will go into Hi Lock but not Low. I've adjusted the linkages and can move one arm by hand but not the other.

I know this is hard to figure with not seeing it but any help or ideas will help. This was my dads truck my whole life and last year my kids and I tore it down to bare frame and rebuilt it. New GM crate high HP engine, with original TH350. Sure appreciate your help.

 

[Turbo4whl]

What oil are you using? Should be 10W-40 motor oil, not gear oil.

The lock in low issue could be a problem with how the unit was converted to part time.

 

[ali_c20]

What oil are you using? Should be 10W-40 motor oil, not gear oil.

The lock in low issue could be a problem with how the unit was converted to part time.

Second that.

The part time kit changes the shift pattern:

4 low

2 low

N

2 high

4 high

Have you tried putting the transmission in neutral no brakes applied (best done on a flat surface )?
It is also recommended that you regularly drive the truck in High Loc (hubs unlocked) about every 200 miles.
This will make sure the reservoir has oil in it to prevent the tail shaft bearings from running dry and being damaged

 

[Is that Normal]

appreciate the feedback guys. My haynes book called for 80w-90 gear oil for conventional and 10-40 for full time so i messed that up. I'll get it drained out and swapped over to 10-40 and update you guys. Ill try the flat ground neutral also. Thanks again.

 

[Is that Normal]

got the linkage to work and go into all ranges with foot off the brake, so awesome thank you.
Question about changing oils is it ok not being able to get every bit of gear oil out and add 10-40w? I'll drain it as much as possible from bottom bolt and jack it up to get as much out as possible but is it ok or do I need to get every last bit out?
Also what is the capacity? I know fill to the bottom of fill plug but curious what it actually calls for, my book doesn't list capacity. Thanks again guys, really appreciate the help.

 

[Turbo4whl]

You should be fine if you get most of the gear oil out. I don't remember the capacity off hand.

 

[Snoots]

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4-1/2 quarts

 

[Snoots]

NP203 Shifter Rebuild

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I couldn't get a good picture of the bolts but there are 2 that hold it to the T Case. Most likely they are already loose. 9/16" takes them out. Lift up on the whole setup and you will see 2 levers connected to it with cotter pins. Remove these and pull it out. The levers just sit there.

Lay it on your hood ( or bench if you prefer) so the bracket is sticking up. You now need to remove the cover. I first took the large nut off since I had better leverage without the other half of the cover being loose. 5/8 and 11/16 should do it.

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Next the 2 small bolts on the right side

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and finally bend the tab on the left side straight and lift off the cover

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Cover is off and this is what you should see

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This is the other side. Make sure you remember the direction they came off.

Continues:

 

[Snoots]

This plate and the hook under it stayed in while I pulled the other things off. You can see how much crap is in there.

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Remove the hook and now it’s time to clean. I used a lubricant spray and some rags. A gasket scraper was used for all the thick stuff. Also, I added grease to any metal parts that are touching, especially the metal pin sticking up.

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Not pictured but don't forget the thin washers between the triangle plate and the one above it, and then the one between the top 2. Putting the large bolt in helps to keep everything from moving around.


Next put the triangle shaped plate in

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Continues again:

 

[Snoots]

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Clean this chrome piece. Shines up good!

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This almost looks like a keychain. A hollow pin slides out of the top of the shifter mechanism and then this pulls out the bottom. Make sure you keep the long end of the spring on the square piece. When putting back in after cleaning the inside where it was, hold the shifter upside down and it will slide right in. When putting the pin in, you may need to apply small pressure to the circle side since the spring pulls on it.

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Clean the housing of previous part while it's out to get anything inside of it out good.

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Continues still:

 

[Snoots]

Now the little tricky part. Have to get aforementioned pin to slide all the way down through all the plates. It was easier to move the top 2 plates onto the shifter and then slide that down onto the bottom piece.

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Now that everything is in, you can replace the cover. I put in the 2 small bolts to hold it in place and then tightened down the large bolt. I do not know the torque specs but it was on pretty tight. Then tighten the 2 bolts and finally bend back the tab.

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This came from 73-87 chevytrucks before the moderators became a-holes.
I did this to my NP203 shifter and it's been great ever since!
Don't forget to do the alignment on the levers too!

THE END

 

[Is that Normal]

You guys are awesome, thank you so much. Really appreciate taking the time to post all that, with pics even. Seriously a huge blessing!

 

[Snoots]

You're very welcome.
Be sure to let us know how it turns out!

 

[Turbo4whl]

@Snoots

Roger, thanks for posting this picture overhaul!

Did you know Hurst Shifters was contracted to design this shifter for New Process Gear?

 

[Snoots]

@Snoots

Roger, thanks for posting this picture overhaul!

Did you know Hurst Shifters was contracted to design this shifter for New Process Gear?

You are welcome!
I only supposed since mine has a HURST shifter.