Have a 79 k10, just bought an 81. Help with swap?

[amorgan93]

So a while back I did a very idiotic thing and traded my 79 F150 SM465 NP205 for a 79 K10. Ive been building on the truck for a while trying to get it running correctly, removed the engine and semi-overhauled it, the TH350 transmission is fairly new (has about 1500 miles on it), but the truck has a lot of other issues. The 12 bolt rear's pinion bearings are way shot even though it still functions, the cab and bed are in bad condition, full of bondo and lots of rust, the frame is cracked at the steering box, the window tracks in the doors are broken, door pins shot, blower motor shot, broken speedometer, broken rear window sliding glass, barely functioning windshield wipers, lots of annoying problems.

A friend of mine has an 81 k10 i can buy for $500 thats in 10x better condition, has some rust but in much better condition than mine, everything electrical works, speedo works, no sagging doors, No frame crack at steering box (the truck has a factory steering box brace), less rusty frame. The truck was a DD until the inline 6 in it gave out.

The 1979 has a 350, TH350, and np203 fixed-yoke transfer case with the part-time conversion. The 1981 has the 3-on the tree (Saginaw, Muncie, i dont know anything about these) converted to floor shifter, np208 aluminum slip-yoke T-case. I dont know how strong the 3-speed saginaw is, in comparison to the TH350, but i assume the TH350 is stronger.?? And Ive read the NP203 with fixed yoke is much better than the np208 with slip yoke. So i cant decide:
1) Use the 350 in front of the 3 speed saginaw, with the np208
2) use the 350 and TH350 with the np208 (if thats possible)
3) swap 350, TH350, and np203 into the 1981, along with driveshafts i assume?? will this all bolt to the crossmember used with the 3 speed and np208?

The truck is sometimes used for hauling gravel, but mostly for offroading, mudding, trails, etc.. my plans for the future would be to lift it 4"-6" suspension and go with 35s or 37s, and a 6 lug 14-bolt semi-floater. Any advice is appreciated.
any advice is appreciated.

 

[amorgan93]

So a while back I did a very idiotic thing and traded my 79 F150 SM465 NP205 for a 79 K10. Ive been building on the truck for a while trying to get it running correctly, removed the engine and semi-overhauled it, the TH350 transmission is fairly new (has about 1500 miles on it), but the truck has a lot of other issues. The 12 bolt rear's pinion bearings are way shot even though it still functions, the cab and bed are in bad condition, full of bondo and lots of rust, the frame is cracked at the steering box, the window tracks in the doors are broken, door pins shot, blower motor shot, broken speedometer, broken rear window sliding glass, barely functioning windshield wipers, lots of annoying problems.

A friend of mine has an 81 k10 i can buy for $500 thats in 10x better condition, has some rust but in much better condition than mine, everything electrical works, speedo works, no sagging doors, No frame crack at steering box (the truck has a factory steering box brace), less rusty frame. The truck was a DD until the inline 6 in it gave out.

The 1979 has a 350, TH350, and np203 fixed-yoke transfer case with the part-time conversion. The 1981 has the 3-on the tree (Saginaw 3-speed), converted to floor shifter, np208 aluminum slip-yoke T-case. I dont know how strong the 3-speed saginaw is, in comparison to the TH350, but i assume the TH350 is stronger. And Ive read the NP203 with fixed yoke is much better than the np208 with slip yoke. So i cant decide:
1) Use the 350 in front of the 3 speed saginaw, with the np208
2) use the 350 and TH350 with the np208 (if thats possible)
3) swap 350, TH350, and np203 into the 1981, along with driveshafts i assume?? will this all bolt to the crossmember used with the 3 speed and np208?

The truck is sometimes used for hauling gravel, but mostly for offroading, mudding, trails, etc.. my plans for the future would be to lift it 4"-6" suspension and go with 35s or 37s, and a 6 lug 14-bolt semi-floater. Any advice is appreciated.
any advice is appreciated.

 

[bluex]

That I6 Trans probably won't last long behind a 350, especially hauling an offroad.

If it was mine I'd take everything from the 79 an put it in the 81. You'll need the motor mounts, Trans cross member, driveshafts, the t-case shifter, column an auto linkages (unless you want a floor shift auto). The best part about it is by having both trucks if something off the 81 doesn't work with the 79 parts you can just go get what you need off the 79.

That's just my opinion though, I believe taking the drive train from your 79 would be better than just swapping motors....

 

[Swims350]

np208 behind a th350 works just fine, they bolt up the same as a 700r4 so it works.

as for needing motor mounts I'm not sure why on the frame side ones. block side yes or course but frame side we had a 2wd which was a 76 had a 6 cyl. in it straight 6, and we put in a 350 never changed a thing, bolted right up.

we also used a 3 spd on the tree behind it and it held up good. in our case the 2wd truck being 3 spd Saginaw a short 6 inch tail th350 fit right in it's place, not sure on the 4wd ones I've never seen a 4wd Saginaw 3 speed.

 

[bucket]

The best thing to do is find out exactly what trans it is. I'm not aware of a 4x4 being offered with a 3 on the tree. Maybe it's actually a 4 speed SM465 or even the elusive A833 4 speed with overdrive.

 

[amorgan93]

That I6 Trans probably won't last long behind a 350, especially hauling an offroad.

If it was mine I'd take everything from the 79 an put it in the 81. You'll need the motor mounts, Trans cross member, driveshafts, the t-case shifter, column an auto linkages (unless you want a floor shift auto). The best part about it is by having both trucks if something off the 81 doesn't work with the 79 parts you can just go get what you need off the 79.

That's just my opinion though, I believe taking the drive train from your 79 would be better than just swapping motors....

dad and a chevy buddy of mine also seems to think this is the best option. So the TH350 is definitely stronger than a 3 speed saginaw? Also the trans cross-member looked exactly the same as whats in my 79. I didn't have them side-by-side to compare, but the design and mounts were the identical, or very close. Either way, its not a big deal to swap over.

np208 behind a th350 works just fine, they bolt up the same as a 700r4 so it works.

as for needing motor mounts I'm not sure why on the frame side ones. block side yes or course but frame side we had a 2wd which was a 76 had a 6 cyl. in it straight 6, and we put in a 350 never changed a thing, bolted right up.

we also used a 3 spd on the tree behind it and it held up good. in our case the 2wd truck being 3 spd Saginaw a short 6 inch tail th350 fit right in it's place, not sure on the 4wd ones I've never seen a 4wd Saginaw 3 speed.

Yep according to Wikipedia it is the 3 speed saginaw. Ive read about rare cases of the 3 speed in 1981 after digging on the internet about 3 hours. I don't see how a trans that's been around for so long would be as weak as some people claim? Also, do you know is the 3 speed longer than the TH350, could i use the NP203 behind the 3 speed, and use the original drive-shafts from the 79? I just don't like the 208 because it is aluminum, but mostly because of the slip yoke, whereas the 203 is fixed.

The best thing to do is find out exactly what trans it is. I'm not aware of a 4x4 being offered with a 3 on the tree. Maybe it's actually a 4 speed SM465 or even the elusive A833 4 speed with overdrive.

It is most definitely the 3 on the tree, shifter linkage is on the side, not the top like an SM465. Oh how i wish it was the SM465. The guy drove it to school for a long time until the motor crapped out. Only reason he converted it to floor shifter was because the column shifter seized up.

Ill be getting better pics tomorrow!

 

[bucket]

The A833 also has the linkage on the side of the case. I'd be real curious to see a pic of this thing, especially how the t-case mounts up if it is indeed a 3-speed.

 

[sticman]

The A833 also has the linkage on the side of the case. I'd be real curious to see a pic of this thing, especially how the t-case mounts up if it is indeed a 3-speed.

Love to see this combo too, Ive only ever seen and had 3speed 2wd's

 

[amorgan93]

ok heres some more pics. Thanks again for all the help!

EDIT: After hours of searching, finally found just one photo of another of these transmissions. Its listed as a Saginaw 3 speed, although no other picture of saginaw 3 speeds looks like it. Notice the resemblance to the 3rd picture i posted.
http://www.pirate4x4.com/forum/engi...inaw-3-speed-colum-shift-tranny-se-kanas.html

 

[amorgan93]

more. The number 2603435 is on the side of the transmission. Also says F.02.78 no clue what that means.

 

[amorgan93]

and...

 

[bucket]

Well that's cool! Never heard of such a thing! I wonder if the t-case has a 27 spline or 32 spline input.

 

[amorgan93]

wanna see something weird? Check out the search results for a Ford 3.03 transmission. You get this >> Look at the resemblence.

1) Oil fill bolt is square and is tilted upward. Also notice the flat spot to the right of the fill bolt. They look identical...
2) neither have side panel, both have rounded sides.

You must be registered for see images attach

 

[bucket]

Yeah, they are definitely very closely related. So I'm not familiar with Furd transmixers, is this a common trans?

 

[sticman]

Holy wow.... You wont see your combo any time soon.

If a original gm release very rare. Three in the tree made your 4x4 unique.
Coming out of the 70's the three in the tree option was so unpopular.

Looks like a Ford top-loader crazy. Broncos are rumored to have come with a top-loaders as well.
Most ford top-loaders are only 2wd just like the GM saginaw's.
All common GM 3 speed manuals have side bolt on covers.

Got to love hecho en México = made in Mexico
I suspect 2603435 is the part number and F.02.78 the date code.
You'll have to go to a dealer and get a build sheet to find out what you got if your interested in knowing more. Guaranteed the dealer parts guy is going to wish you never walked in.

Gm did some different stuff if you ordered a truck with 3 speed on the column such as the offering of the dana 20 as an option when combo-ed with 3 in the tree. Rumor has it for years 69 to 74 you could get a combo of saginaw 3 speed coupled to dana 20 for GM.

Thanks for sharing... Cool GM things to see and learn.