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**hatzie** · 10-08-2018, 12:03 AM

You're mixing GMT800 & GMT400 parts...
Sounds like you have the wiring at the transfer case sorted out... however the controllers on the GMT800 are a bit more tightly integrated than the old T400 chassis.
The GMT800 NP8 (NV246) and the GMT800 NP1 (NV263) use a different 4x4 controller or at least a different program in the controller. You may get away with using the NV263 electronics for the 1997 NP1 (NV243C)... It may be as simple as getting the 3 button switch and 4x4 control box from another 99 but probably not. It's probably easier to get an NP2 (NV261) from a 2500HD or a NV241C from a T400 and put a stick on the floor.

10-08-2018, 12:03 AM	#3
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,912	Re: Transfer wiring question You're mixing GMT800 & GMT400 parts... Sounds like you have the wiring at the transfer case sorted out... however the controllers on the GMT800 are a bit more tightly integrated than the old T400 chassis. The GMT800 NP8 (NV246) and the GMT800 NP1 (NV263) use a different 4x4 controller or at least a different program in the controller. You may get away with using the NV263 electronics for the 1997 NP1 (NV243C)... It may be as simple as getting the 3 button switch and 4x4 control box from another 99 but probably not. It's probably easier to get an NP2 (NV261) from a 2500HD or a NV241C from a T400 and put a stick on the floor. __________________ 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. Last edited by hatzie; 10-08-2018 at 12:20 AM.