Discussion - NP203 Transfer Case Failures - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76k10 · 10-03-2012, 05:52 PM

If anyone has broken a NP203 transfer case internally, please tell us how.

I feel like the 203 has a bad reputation, but (like a 12 bolt) I never hear about them actually breaking.

csb#356 · 10-03-2012, 06:10 PM

I have only had one that broke. When you spun the tires locked in 4 wheel drive it would make a ferocious clunking sound. I didn't take it apart to see what actually was going on but I figured it was probably the chain jumping around but not sure. The problem with the one I have now is that there is some slack in the chain and clunks when going into reverse. This case has been in full time four wheel drive configuration since 1979.

Redcap · 10-03-2012, 06:16 PM

I have owned a few vehicles with NP203s over the years. Chain failures, drive sprocket failures and windowing the passenger side of the low case section are all pretty common. They also burn up fairly easily, even with a lightweight oil.

They are one of the first things I swap out.

vidman · 10-03-2012, 06:21 PM

Best thing to do is stay away from them. The two i had the chain and sprockets went. The last one i had i put a part time conversion in it and it did last longer but not by much..

Mike C · 10-03-2012, 08:33 PM

The high/low box is run with NP205 all the time to make a doubler setup, and in that format they are tough. So it looks like the chain and sprockets is the weak point, but obviously, the chain is the weak link in most of the chain drive cases. If it's in good shape, just run it.

76k10 · 10-03-2012, 08:36 PM

Quote:

Originally Posted by Mike C

The high/low box is run with NP205 all the time to make a doubler setup, and in that format they are tough. So it looks like the chain and sprockets is the weak point, but obviously, the chain is the weak link in most of the chain drive cases. If it's in good shape, just run it.

Mine is in good shape, I just like reading about this stuff.

SunSoaked · 10-03-2012, 08:46 PM

Quote:

Originally Posted by 76k10

Mine is in good shape, I just like reading about this stuff.

Go with what Redcap says. He gets everything for cheap and nothing ever fails.

kenbob87 · 10-16-2012, 01:29 AM

i have destoryed 3 203's before i swapped it out for a 205. the chains would always slip and on two of them i broke the front output shafts. but i ABUSE mine it is strickly a mud truck so it always under alot of load at the time i was running 35x15.5 thornbirds i also had alot of problems keeping my 203's in low range too

10-03-2012, 05:52 PM	#1
76k10 Registered User Join Date: Apr 2012 Location: Tuscaloosa, AL Posts: 131	Discussion - NP203 Transfer Case Failures If anyone has broken a NP203 transfer case internally, please tell us how. I feel like the 203 has a bad reputation, but (like a 12 bolt) I never hear about them actually breaking.

10-03-2012, 06:10 PM	#2
csb#356 Registered User Join Date: May 2009 Location: Pinehurst, Idaho Posts: 311	Re: Discussion - NP203 Transfer Case Failures I have only had one that broke. When you spun the tires locked in 4 wheel drive it would make a ferocious clunking sound. I didn't take it apart to see what actually was going on but I figured it was probably the chain jumping around but not sure. The problem with the one I have now is that there is some slack in the chain and clunks when going into reverse. This case has been in full time four wheel drive configuration since 1979.

10-03-2012, 06:21 PM	#4
vidman Registered User Join Date: Jun 2012 Location: Fitchburg,Mass Posts: 737	Re: Discussion - NP203 Transfer Case Failures Best thing to do is stay away from them. The two i had the chain and sprockets went. The last one i had i put a part time conversion in it and it did last longer but not by much.. __________________ 62 Willys 4wd Pickup : 72 C-10 swb 504 stroker 09 Taco 3" lift 33" tires: 90 K-5 blazer (plow truck): RIP Ross Little brother

10-03-2012, 08:33 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: Discussion - NP203 Transfer Case Failures The high/low box is run with NP205 all the time to make a doubler setup, and in that format they are tough. So it looks like the chain and sprockets is the weak point, but obviously, the chain is the weak link in most of the chain drive cases. If it's in good shape, just run it. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

10-16-2012, 01:29 AM	#8
kenbob87 Registered User Join Date: Oct 2012 Location: South Haven, MN Posts: 109	Re: Discussion - NP203 Transfer Case Failures i have destoryed 3 203's before i swapped it out for a 205. the chains would always slip and on two of them i broke the front output shafts. but i ABUSE mine it is strickly a mud truck so it always under alot of load at the time i was running 35x15.5 thornbirds i also had alot of problems keeping my 203's in low range too

10-03-2012, 06:16 PM	#3
Redcap Registered User Join Date: May 2010 Location: Lewis County, WA Posts: 1,523	Re: Discussion - NP203 Transfer Case Failures I have owned a few vehicles with NP203s over the years. Chain failures, drive sprocket failures and windowing the passenger side of the low case section are all pretty common. They also burn up fairly easily, even with a lightweight oil. They are one of the first things I swap out.



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