The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

**hatzie** · 03-13-2021, 07:56 PM

You don't need a 205 because the chain drive cases are "Weak".
The NP205 is 1.96:1 low range, the NP208 is 2.62:1 low range and the NP241 is 2.72:1 low range.
The NP241 with the correct drop for the RV squarebodies is not as plentiful as the T400 CK version but it has the best low range and it's not so popular that it costs a mint to buy.

As far as weak goes...
I've plowed snow with a 78 W200 Power Wagon 360/A904 with a "weak" NP203, an '86 F250 with an NP208 transfer case behind a C6 & 460, and an '89 GMT400 K2500 with a NP241 transfer case behind a 4L60 and a 350. I flogged all three of them like a red headed step child.
The equipment dead list included the Ford Dana 44 IFS front axle that I swapped out to a Dana 44 straight axle, two 4L60 transmissions, and one A904 transmission gave up on me but that NP208 was not a problem no matter how hard I worked it and neither was the dead stock NP203.
The 460 was pretty rough on the wallet at the gas station with the 4.10 gears in that F250 tho.

03-13-2021, 07:56 PM	#13
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,915	Re: FINALLY got Old Green after 20 years. You don't need a 205 because the chain drive cases are "Weak". The NP205 is 1.96:1 low range, the NP208 is 2.62:1 low range and the NP241 is 2.72:1 low range. The NP241 with the correct drop for the RV squarebodies is not as plentiful as the T400 CK version but it has the best low range and it's not so popular that it costs a mint to buy. As far as weak goes... I've plowed snow with a 78 W200 Power Wagon 360/A904 with a "weak" NP203, an '86 F250 with an NP208 transfer case behind a C6 & 460, and an '89 GMT400 K2500 with a NP241 transfer case behind a 4L60 and a 350. I flogged all three of them like a red headed step child. The equipment dead list included the Ford Dana 44 IFS front axle that I swapped out to a Dana 44 straight axle, two 4L60 transmissions, and one A904 transmission gave up on me but that NP208 was not a problem no matter how hard I worked it and neither was the dead stock NP203. The 460 was pretty rough on the wallet at the gas station with the 4.10 gears in that F250 tho. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.