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Should I rebuild the np203?

wazzabie

wazzabie

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In the 78 K5 I swapped in a np205 from a 72 K5. I took out the np203 because it made noise. I assume chain slip in the np203. Someone gave me for free a np203. So I have two np203s. I don't know the state of the free np203. I've thought about going full time 4x4 with the np203.
 
If it were in the truck already set up and functional just needing a rebuild, I’d say yes every time.

Since the truck has already been 205 swapped, I’d say the work to get it back in is not worth the benefit.
 
A full-time case would be great in serious snow conditions but parts for 203’s are getting very hard to come by.
You can get seals, gaskets and bearings all day long but a quality chain and new sprockets are almost always needed and can’t be had new anymore.
This means you will most likely end up with a resealed and fresh bearings 203 instead of a truly “rebuilt” case - in other words, a lot of effort for not gett’n the ball in the end zone.

Besides you’ll have to lengthen and shorten your driveshafts again.

Like said above , keep what ya got - besides the 205 is king of reliability!
 
Seems like I read that no one makes chains for them anymore, if true I wouldn’t waste my time on it unless you were building the range box for a Doubler.
 
nvrenuf said:
Seems like I read that no one makes chains for them anymore, if true I wouldn’t waste my time on it unless you were building the range box for a Doubler.
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I feel bad these days for sh!t-caning so many 203 cases - we would throw them in the trunk of cars being scrapped to add weight.
We would remove the yokes because they interchanged with the 205’s and put what was left in the scrap pile - it’s a damn shame we killed so many good cases…

We had no idea that things like a Doubler were on the horizon.
 
I assume that it is a loose chain. When the np203 was last in the K5 when I would put it in drive I would hear a load grinding noise. Maybe a fork misalignment?
 
That’s great news about the chain but putting a new chain on worn sprockets won’t buy much time ( or miles ).
The sprockets will wear down the new chain very rapidly and excessive slop and slippage will be returned.
Just something to think about before you invest in the other rebuild parts.
 
The list link I posted comes with chain and sprocket for 135. I would confirm with seller.
 
tarussell said:
Didn’t know that - might be some hope left for those old boat anchors after all!
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I called them last year when I was considering rebuilding mine. It was going to be almost $700 with shipping for a chain and sprockets. If I was still driving the truck in snowy weather it might be worth it but I decided to swap a 208 in instead. I do occasionally see NOS sprockets pop up on ebay as well.
 
Chickntrk said:
I called them last year when I was considering rebuilding mine. It was going to be almost $700 with shipping for a chain and sprockets. If I was still driving the truck in snowy weather it might be worth it but I decided to swap a 208 in instead. I do occasionally see NOS sprockets pop up on ebay as well.
Click to expand...
Was the 208 a direct swap in? The 205 was an easy swap. All I needed custom was new drive shafts.
 
tarussell said:
A full-time case would be great in serious snow conditions but parts for 203’s are getting very hard to come by.
You can get seals, gaskets and bearings all day long but a quality chain and new sprockets are almost always needed and can’t be had new anymore.
This means you will most likely end up with a resealed and fresh bearings 203 instead of a truly “rebuilt” case - in other words, a lot of effort for not gett’n the ball in the end zone.

Besides you’ll have to lengthen and shorten your driveshafts again.

Like said above , keep what ya got - besides the 205 is king of reliability!
Click to expand...
I saved my old 203 drive shafts before I did the swap. For the 205 swap I had new drive shafts made. Parts are spending for the 203. I wonder if the used chain and sprocket is good on the spare used 203 that was given to me if I should just swap it into my old 203. The old 203 has the part time conversion kit which I would revert. I would like to have the option some day to return to full time 4x4.
 
wazzabie said:
Was the 208 a direct swap in? The 205 was an easy swap. All I needed custom was new drive shafts.
Click to expand...
No, because I have a TH400. The TH400 tailshaft for the NP203 is an oddball, its the shortest of all the output shafts. You would need to swap the output shaft in the trans (I swapped the entire trans). If you have a TH350 its a direct swap minus drive shafts.
 
wazzabie said:
I saved my old 203 drive shafts before I did the swap. For the 205 swap I had new drive shafts made. Parts are spending for the 203. I wonder if the used chain and sprocket is good on the spare used 203 that was given to me if I should just swap it into my old 203. The old 203 has the part time conversion kit which I would revert. I would like to have the option some day to return to full time 4x4.
Click to expand...
If you ever seriously thought about eventually wanting the full time 203 again ya might want to purchase these chain and sprockets now - I would assume that they will only go up in price and eventually fade away as the demand lessens over time.
The last NP203’s were made in 1979 so get these parts while the aftermarket still holds a value for them.
 
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