Trying to figure out what transfer case I have.

[Godfather240sx]

I have a 76 K5 blazer that I'm getting ready to fix up and get back on the road. It has a 350 and an auto trans. I have read some of the other treads to see if it will help me figure out my transfer case but they have not helped. The thing that's different from all the transfer cases I have heard discribed in the other threads is the shift patern. Starting the whole way front and working back it has L LOC - L - N - H - H LOC. I'm guessing that the L and H LOC would by low and high four wheel drive and the L and H would be low and high two wheel drive, is that correct? The Trans is shot and I'm checking prices to rebuild or replace it. If I replace it I want to find a Trans that will work with this transfer case.

Thanks in advance for any help you can give.
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[72shorbox]

Looks like you have the NP 203 transfer case.

[Godfather240sx]

Ok. Thanks.
Like I said the L and L loc is what was throwing me off.
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[Godfather240sx]

So would L be two wheel low and L LOC be four wheel low? I was reading that some of the NP 203's where full time four wheel drive and some where converted to part time four wheel drive? I know the blazer has locking hubs and I always used the L and H with the hubs unlocked and the L LOC and H LOC with the hubs locked in.
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[72shorbox]

you would be correct on "L" for 2wd low range and "L LOC" for 4wd low range.

[Godfather240sx]

Thanks for the help.
By your name I take it you own one of my favorite model trucks. The first thing I bought when I was 16 was a 72 c10 (long bed) and I wish I still had it. I have been looking for another one for years but you can't find them in decent shape for a decent price anymore. I just got a lead on a 72 k5 two wheel drive that I want to check out.
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[motornut]

thats how my 78 203 is ,don't know whats in it but
I read a mile marker kit will do it

[RoughKuntry]

Motornut, Thanks for the information, I have the same Transfer case In my 79 Jimmy, however I can not tell the transmission, besides it being a 4 Speed. The transfer case, states Model 203, Ratio 201, Serial 11 2 79. What is odd is I don't have a transmission pan, only a bolt at the bottom where I can drain the Transmission Fluid. Have any Suggestions?
_________________________
1979 GMC High Sierra Jimmy 4x4
1973 GMC 350-4 V8 2500 4x4
1984 Chevy Dully Crew Cab 454 V8 4x2

[motornut]

Originally Posted by T.Rokk

Motornut, Thanks for the information, I have the same Transfer case In my 79 Jimmy, however I can not tell the transmission, besides it being a 4 Speed. The transfer case, states Model 203, Ratio 201, Serial 11 2 79. What is odd is I don't have a transmission pan, only a bolt at the bottom where I can drain the Transmission Fluid. Have any Suggestions?
_________________________
1979 GMC High Sierra Jimmy 4x4
1973 GMC 350-4 V8 2500 4x4
1984 Chevy Dully Crew Cab 454 V8 4x2

4 speed with overdrive uses ATF
others use 80W oil
should have an upper bolt for check/fill
lower to drain it

[RoughKuntry]

Originally Posted by motornut

4 speed with overdrive uses ATF
others use 80W oil
should have an upper bolt for check/fill
lower to drain it

I don't have overdrive. only L, 1, 2, 3, R on the Shifter, with a 203 Transfer case

[motornut]

Originally Posted by T.Rokk

I don't have overdrive. only L, 1, 2, 3, R on the Shifter, with a 203 Transfer case

then it should be 80 oil
but when you drop it you will tell too
203 is 10/30 or 10/40 oil

[83GMCK2500]

Originally Posted by T.Rokk

I don't have overdrive. only L, 1, 2, 3, R on the Shifter, with a 203 Transfer case

Your manual trans is an SM-465, look: HERE

To the OP and others, NP203 clarification: HERE (scroll past diagram)

[motornut]

Originally Posted by 83GMCK2500

Your manual trans is an SM-465, look: HERE

To the OP and others, NP203 clarification: HERE (scroll past diagram)

some good info there

[jon75]

Your transfer case is a "full time" case, according to the GM owner's manual. Part-time cases only have L-N-2H-4H for modes.

[motornut]

Originally Posted by jon75

Your transfer case is a "full time" case, according to the GM owner's manual. Part-time cases only have L-N-2H-4H for modes.

yes but with a "mile marker" brand kit it makes it part time too
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[RoughKuntry]

Its really hard to say, because I haven't gotten that far yet about taking the transmission and transfer-case out. I still am working on getting a Steering Column from Mike.