What fluid in NP203??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dale DuBose · 01-13-2003, 03:05 PM

So what kind of fluid goes in this thing? I do have a part-time kit in it. Thanks.

Tuffold72 · 01-13-2003, 03:56 PM

The service manual calls for 30W. If your running a part time kit, make sure you put it in 4x4 at least 1 time every to weeks and drive a few hundred feet. This puts oil back in the rear output shaft bearing area.

**MJN** · 01-16-2003, 12:21 AM

my book says 10w40

79Silv4x4 · 01-16-2003, 04:09 AM

10W40 in mine too.

silvereagle1770 · 01-16-2003, 10:44 PM

thats what the books say i run 80 90 in mine have been for 3 years hasent gave me no problems the oil just dont seem thick enough to me

wg77 · 01-21-2003, 03:36 AM

30wt,40wt,80w90,it all works,throw some Lucas oil stabilizer in,that will make any gearbox work smooth.

NAPCO ken · 01-21-2003, 12:20 PM

203s all use 10W40. I have an NP205 in my 88 crewcab dually, and it uses ATF!!! I thought about putting gear oil in there instead, but that's what the factory put in, and they have just a tad bit more engineering experience than me, so I left the ATF in it.

Mudder · 01-21-2003, 12:50 PM

10w40 in a 203

01-13-2003, 03:05 PM	#1
Dale DuBose Registered User Join Date: Oct 2002 Posts: 27	What fluid in NP203??? So what kind of fluid goes in this thing? I do have a part-time kit in it. Thanks. __________________ I need all the help I can get.

01-16-2003, 12:21 AM	#3
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	my book says 10w40 __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com

01-16-2003, 04:09 AM	#4
79Silv4x4 Workaholic Join Date: Oct 2002 Location: Katy, TX Posts: 1,589	10W40 in mine too. __________________ 1979 K-10 Silverado (work in progress) 1991 V1500 Subruban 1999 Suburban LT 4x4 2006 Suburban LTZ (daily driver)

01-16-2003, 10:44 PM	#5
silvereagle1770 Registered User Join Date: Oct 2002 Location: michgan Posts: 57	thats what the books say i run 80 90 in mine have been for 3 years hasent gave me no problems the oil just dont seem thick enough to me __________________ 79 4x4 short box

01-21-2003, 12:20 PM	#7
NAPCO ken Registered User Join Date: Aug 2001 Location: anaheim, ca Posts: 187	203s all use 10W40. I have an NP205 in my 88 crewcab dually, and it uses ATF!!! I thought about putting gear oil in there instead, but that's what the factory put in, and they have just a tad bit more engineering experience than me, so I left the ATF in it. __________________ ken '58 Chev NAPCO 4x4 short '60 GMC Suburban 4x4, restored '60 GMC 3/4T stepside 4x4 '64 GMC Suburban 4x4, restored '90 Chev Suburban 4x4, dually, ZZ502 '77 GMC Suburban 4x4, one ton axles, 12" lift, 39.5"s '88 Chevy crewcab dually 4x4, 10" lift, 42"s (x6!) '03 Jeep Wrangler Rubicon '79 Chev 3/4 Suburban 4x4, 400-400-203

01-13-2003, 03:56 PM	#2
Tuffold72 Registered User Join Date: Oct 2002 Location: Oregon Posts: 69	The service manual calls for 30W. If your running a part time kit, make sure you put it in 4x4 at least 1 time every to weeks and drive a few hundred feet. This puts oil back in the rear output shaft bearing area.

01-21-2003, 03:36 AM	#6
wg77 Registered User Join Date: Jan 2003 Location: Verona, PA Posts: 23	30wt,40wt,80w90,it all works,throw some Lucas oil stabilizer in,that will make any gearbox work smooth.

01-21-2003, 12:50 PM	#8
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	10w40 in a 203



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