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Looking to up-grade my K5 trans and case

L

liljoe8865

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I am a new B and my 1979 k5 chevy cheyenne full time 4x4 just went out it's original np203 case but i dont know what the tranny is I just wanted to know what would be the easy way to up-grade or replace it i would like to replace both at the same time dont want the full time no more. The truck has the axel swap in front and back 8 lug i just want an easy replacement and what would be recommended thanks alot happy new year from LIL joe
 
First off, welcome aboard!
I'm not sure without a little more info, there are other guys that can tell you for sure. Because I try to stay up on the '80's stuff. But, You either have a TH350 or a TH400.
Do you have a small block or big block? Probably Small block, 350CID or 400CID? Probably a TH400 transmission just because you said you have the 203 Transfercase.
Or you could check your RPO codes. 3 digit codes on a sticker inside your glovebox.

Oh, and what ever you do, save your Transfer case for your doubler that you will undoubtedly build , now that we have our claws in ya".
 
thanks for the reply but i do have a 350 in it the trans and case are shot just happened on friday during a quick trip to get lunch at work i just wan to replace as easy as possible
 
He will have a TH350/203 combo as GM never put a TH400 into a blazer. He will also have a SBC as GM never put a BBC into a blazer either.
 
Thats a start thanks i love Blazers (K5) just as much as anyone in here I want something that would just bolt right up with no probs Thanks guys
 
4X4HIGH said:
He will have a TH350/203 combo as GM never put a TH400 into a blazer. He will also have a SBC as GM never put a BBC into a blazer either.
Click to expand...

My memory must be shot. I remember my best friend's 76 Blazer having a smallblock 400 CID, AND a TH400, and a 203. But, that was a lot of years ago. Might have all been swapped in????:confused: OK memory is shot.
 
4X4HIGH said:
He will have a TH350/203 combo as GM never put a TH400 into a blazer. He will also have a SBC as GM never put a BBC into a blazer either.
Click to expand...
Take it easy with the never.
They did put th400 in blazers with the SBC400 as an option.
Only in the 70's though not sure it went all the way to 79 but I know I had a 76 with the 400/400/203
But with the 350 SBC it would be a th350/203 which is the most common setup there is.
 
should i just try to rebuild or replace with diffrent set up and what would be recommended i do like going MUD BOGGING if i do replace i would want to do i right so my toy can handle the terrains if i spend money it wont hurt to get a decent set up what is recommended thanks guys
 
liljoe8865 said:
i just want an easy replacement
Click to expand...

Easiest would be to rebuild your tranny/tcase combo. You can install a part time kit in the 203 which would be a nice upgrade.

After that, the possibilities are almost endless, but you will run into other issues like drive lines, sourcing cross members, ect...
 
i will take that to mind i seems to be the best thing to do But everything for sale out there seems to be np205s ect ect never can find what you need till its to late
 
4X4HIGH said:
He will have a TH350/203 combo as GM never put a TH400 into a blazer. He will also have a SBC as GM never put a BBC into a blazer either.
Click to expand...

oh man 4x4high is so wrong . :eek1:

m1009 got th400 factory :whistle::thumb:

.
.
.
..
and everyone is missin the easy clue tothe tranny id.

th350 has square pan with 1 corner 45 cut off.

th400 has texas shape pan .

super easy to spot this way .
 
good info i will look tomorrow truck is sitting at mother in laws house all alone and broken somebody has to know what would be a good replacement for the truck trying to replace trans and case all in one shot?
 
The only direct replacement will be another TH350/NP203 combo. You could go with a TH350/NP205 combo but then you'll need to do driveshafts and possibly move the crossmember and get the NP205 shifter as well.
 
thats sounds like something i wanted to hear nothing but the original is going to bolt right up so a TH350/np205 with shifter sounds easy now what would need to happen with the drive shafts the truck has a six inch lift i wish i could post pict but iam new and still a bit new with site thanks
 
th350 and 400 are super trannys. just have it rebuilt and smack it all back in and drive it.

turbos = turbo tranny slang word i bet.
 
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