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Old 10-24-2001, 09:05 PM   #1 (permalink)
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Post Converting NP203 back to FULL-TIME.

I've already swapped the locking/freewheeling hubs out for the full-time gear slug, and as far as I can tell all I need to change is the dummy diff carrier with the bolted on output shaft for the original diff assembly with output shaft.

Am I right in thinking this, or is there more to it? I've already got the case stripped on the bench with a new bearing, seal and chain kit standing by.

Also, I've posted in the want section for an un-converted NP203 so I can scavange the diff. Just thought I'd mention it here in case someone reading this happens to have one laying around. I'll pay a fair price and pick it up to boot!...must be in Sacramento or San Francisco area.

Tim: (415) 215-1863 <IMG SRC="smilies/usa.gif" border="0">

PS: Does anyone know how to tell if a 203 has been converted to part-time without splitting the case? I'm sure it's just a matter of spinning the shafts and seeing how they respond but I can't seem to figure it out. Thanks in advance.

[ 10-24-2001: Message edited by: havespine ]
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Old 10-24-2001, 10:49 PM   #2 (permalink)
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why are you swaping out the part time kit?? most people swap that kit INTO their trucks. It puts a hell of alot more stress on your front end haveing it run full time.
PS-i dont know how to tell if you already have the kit in the transfer case
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Old 10-25-2001, 07:38 AM   #3 (permalink)
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Quote:
Originally posted by havespine:
<STRONG>I've already swapped the locking/freewheeling hubs out for the full-time gear slug, and as far as I can tell all I need to change is the dummy diff carrier with the bolted on output shaft for the original diff assembly with output shaft.

Am I right in thinking this, or is there more to it? I've already got the case stripped on the bench with a new bearing, seal and chain kit standing by.

Also, I've posted in the want section for an un-converted NP203 so I can scavange the diff. Just thought I'd mention it here in case someone reading this happens to have one laying around. I'll pay a fair price and pick it up to boot!...must be in Sacramento or San Francisco area.

Tim: (415) 215-1863 <IMG SRC="smilies/usa.gif" border="0">

PS: Does anyone know how to tell if a 203 has been converted to part-time without splitting the case? I'm sure it's just a matter of spinning the shafts and seeing how they respond but I can't seem to figure it out. Thanks in advance.

[ 10-24-2001: Message edited by: havespine ]</STRONG>
Really depends on the part time kit you have. If it has that POS Superlift then the cross shafts that the spider gears ride on will be screwed up and you will need to find a good cage as well as the funky concave spacer washer ( I had a hell of a time finding those when I replaced a supershit kit that ws in one of my trucks when bought it). If it has the low end Mile marker/nash kit then all you need is the gears. If it has the high end MM/Nash kit your going to need the whole output shaft and spider gear assembly.
You will notice a flat thrust roller bearing. That needs to go. It's part of the part time kit. Be carefull with the preload on the tail shaft. should have about 1 thousands end play. To much and it will beat up the gears.
Don't spin that chain while it's apart. there is 122 roller bearings that will fall out of the inside of the top gear (been there played that game of pick up before). I had to convert my 75 trail truck since I'm locked front a rear but I think for winter I'm pulling the lockright out of the front and going back fulltime so not interested in selling the parts..sorry. I am part of rescue group for winter emergency's and that fulltime sure will get some use if we get a bad winter.
I really like the full time and unless you got the top end mile marker kit I think the case is strong not converted. It also was designed to oil with the chain and in part time people run the tail shaft bearings dry and burn them up. Inspect those bearings while you got it appart.
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Old 10-25-2001, 07:05 PM   #4 (permalink)
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Thanks Grim Reaper, just the kind of experienced advice I was looking for.

Do you know how to tell if a removed case has been converted without splitting it?

Not sure who made the kit but it looks like a complete replacement of the entire diff cage and gear assembly. It has 2 parts: a heavy bowl shaped hunk of metal that resembles the original cage with a bolted on output shaft. The shaft has a bolt flange the same diameter as the cage, they simply mate together into a locked assembly. The original input shaft with the pinion/sun gear is still in place, but the gear dosn't do anything anymore. So it looks like I need to replace the entire diff cage/gear assembly and output shaft. Hopefully I can pick up an unconverted case and scavenge the parts.
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Old 10-26-2001, 10:36 AM   #5 (permalink)
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Quote:
Originally posted by havespine:
<STRONG>Thanks Grim Reaper, just the kind of experienced advice I was looking for.

Do you know how to tell if a removed case has been converted without splitting it?

Not sure who made the kit but it looks like a complete replacement of the entire diff cage and gear assembly. It has 2 parts: a heavy bowl shaped hunk of metal that resembles the original cage with a bolted on output shaft. The shaft has a bolt flange the same diameter as the cage, they simply mate together into a locked assembly. The original input shaft with the pinion/sun gear is still in place, but the gear dosn't do anything anymore. So it looks like I need to replace the entire diff cage/gear assembly and output shaft. Hopefully I can pick up an unconverted case and scavenge the parts.</STRONG>
As for checking if it has a kit or not. get the case in gear. hold the input shaft so the the gear box doesn't spin. On the chain section above the front output is the linkage that locks the center diff. puiing it forward will make sure it's not in lock. Try to spin the tail shaft. If the case is part time you will fight the imput shaft your holding and will not spin. if converted it will sping the front output.
Not sure what kit you have. have you taken the bolts out of the cage and seperated it? The MM shaft kit replaces the cage so it's not used. Here is a link to that kit www.off-road.com/chevy/mm-np203/
The cheaper MM kit you take the 4 bolts out of the cage and split it. Take the 4 spider gears off the cross. Put the 4 locking tabs on. engage the tabs with the rear output shaft. Then one side of the cage over the output so it locks it all as one unit. Still some slop in it but it does the job.
So let me get this right. the kit you have you discard half the cage, retain the cross for the slines and bolt the other half of the cage to it?
If you kit bolts to the cage that's a different one yet. I might be a older Nash kit (MM bought the stuff from the Nash estate) and MM may have redisigned it to eliminate the need for the cage.
Any way you could post some pictures of it. Curious to see it.
I might be interested in the kit when you get done converting it back. Let me know if you interested in unloading it.
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Old 10-27-2001, 11:25 PM   #6 (permalink)
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Sorry Reaper, I don't have a digital camera. But based on what you've told me and what I've learned since my kit is not MM and not supershit. But quality wise it's almost as good as MM's 1 piece shaft. It has two pieces: An output shaft has a 5 or 6" diam. flange which mounts directly to a large heavy hub of the same diam. The hub looks similar to the original diff cage, but there's no spider shaft or cross drillings, it's solid with a splined center hole for the input shaft and synchromesh gear teeth on the outer (internal) circumference. This is where the syncrhro selector on the input shaft engages. Compared to those cheaper setups it's definitely a more solid design.
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Old 10-29-2001, 10:43 AM   #7 (permalink)
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Quote:
Originally posted by havespine:
<STRONG>Sorry Reaper, I don't have a digital camera. But based on what you've told me and what I've learned since my kit is not MM and not supershit. But quality wise it's almost as good as MM's 1 piece shaft. It has two pieces: An output shaft has a 5 or 6" diam. flange which mounts directly to a large heavy hub of the same diam. The hub looks similar to the original diff cage, but there's no spider shaft or cross drillings, it's solid with a splined center hole for the input shaft and synchromesh gear teeth on the outer (internal) circumference. This is where the syncrhro selector on the input shaft engages. Compared to those cheaper setups it's definitely a more solid design.</STRONG>
Neat! I wonder who made that one. I bet it's an old Doug Nash kit. Mile Marker bought them and I bet the redisigned it to be a single peice instead of using the outer ring. Pretty cool. I bet it's just as strong as the MM single peice.
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