1979 K25 Automatic NP203 or NP205

[Loww]

Hi,

I'm about to buy a 1979 GMC K25 . I read, that the 1979 Automatics had Full-Time 4WD and the NP203 transfer case. But this one has manual locking hubs on the front wheels and the transfer case lever has four positions: 4L, N, 2H, 4L. Did GM switch to the NP205 during the model year 1979 or how can this be explained?

Thanks

 

[Charlie]

 

[K201979]

Not sure on that but my 79k20 has th400/203. I put manual hubs on so i could use high lock to get around while i was saving for a front shaft and not b turning the front diff. The 4 positons on the stick does tell me 205 tho. Someone probly swaped it. Welcome!

 

[bucket]

In 40 years, there's a lot of parts swapping that could have went on. Many (most actually) would call the 205 an upgrade.

 

[dvdswan]

Some vehicles were order with auto trans and manual hubs. So this is not unheard of. A friend had a 80 Jimmy with manual hubs and 205 from the factory, his father ordered it that way. Yes, IMO, it is an upgrade since it is an all gear t/case.

 

[bucket]

Some vehicles were order with auto trans and manual hubs. So this is not unheard of. A friend had a 80 Jimmy with manual hubs and 205 from the factory, his father ordered it that way. Yes, IMO, it is an upgrade since it is an all gear t/case.

All '80 models came with the 205 and locking hubs, there was no other option that year.

Other than '73 models, '80 models, and 6cyl trucks some years, trucks with automatics got the 203 case and no locking hubs.

Many many many 203 trucks had locking hubs swapped in, often times without the 203 being converted. And in the decades since then, many trucks have had the drivetrains swapped a time or two. Or three or four even.

 

[Loww]

Thank you! Is it an easy swap (205 for a 203)? I mean, is it like experimental or more like a standard modification? Will it make future repairs more difficult, because of non-standard parts?

 

[dvdswan]

Curious, why do you want to go to a 203? They are heavier, have a chain, and linkage needs to be adjusted periodically. 205 is lighter, gear driven, simple, and strong. Swapping the 2 you will need the correct trans to t/case adapter and change your drive shafts IIRC.

All '80 models came with the 205 and locking hubs, there was no other option that year.

Other than '73 models, '80 models, and 6cyl trucks some years, trucks with automatics got the 203 case and no locking hubs.

Many many many 203 trucks had locking hubs swapped in, often times without the 203 being converted. And in the decades since then, many trucks have had the drivetrains swapped a time or two. Or three or four even.

Learn something new everyday. I never knew this.

 

[mgarland]

Don't worry about the 205 and future repairs, if you change the fluid in it and it looks ok then run it and don't look back. It was the best case GM ever put in a truck and they a virtually trouble free.
Mark

 

[71RAT]

Don't worry about the 205 and future repairs, if you change the fluid in it and it looks ok then run it and don't look back. It was the best case GM ever put in a truck and they a virtually trouble free.
Mark

X's 2 for the NP205
Nothing is bullitt proof, a 205 is as close as you can get!

 

[mgarland]

X's 2 for the NP205
Nothing is bullitt proof, a 205 is as close as you can get!

I agree, I've seen many 750 to 1000hp big block pulling trucks with a 205 in them and they are fairly trouble free. I've never hurt one and I have been mean to a few of them.
Mark

 

[shiftpro]

Yup ^^^^

Plus you can twin stick the 205 for more control and man points.