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NP205 Swap

Mastiff

Mastiff

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I need to be educated a little. I have TH400 that is adapted to my original NP208 (1983 K5). Should the 205 bolt right up to the TH400? What else would be involved in making the swap? Rear driveshaft is a given, how about front? Can I make the shifters work and look right without hacking my tunnel?

Here's a pic of my current setup at the connection:

20131222_100429.jpg


I've been struggling with whether to SYE my 208, find a 241 and put a SYE on it, or try to go 205. I found a 205 near me on craigslist, and the bullet proof-ness is appealing, though the loss in gearing is a bummer.
 
It would have to be a 205 and matching adapter that was originally mated to a th400 as the th350 and 465 versions had different spline counts. I think you can do an input shafts swap if you found one that matched your 400 output, but I believe it requires machine work to the case.

400= 32 spline
350/700r4= 27 spline
Older 465= 10 spline
85? And newer 465= 32 spline

I am not sure if the 32 spline version from a newer 465 will work or not. Someone with more knowledge will hopefully post. :dunno: :whistle:
 
need a 32 spline input 05 with adaptor for th400

look at the chart for tail shaft diffrences . this will get you the correct 205 input style needed.

yes drive shaft tube length rework will be needed.

and 205 had slip yoke on lots of them . but stupid easy to get parts to swap it to fixed yoke.

floor shifter hole needs little rework . but should be fine.

np205 short input = fig 8 adaptor style 84 - older
np205 long input = round 6 style. 85-up

your pic shows 85-up crossmember besign already so shoot for the 85-up 205 design .

400 shaft pics.jpg
 
hell I blew up a 208 with 35" tires. and wimpy 350 .

if you want that kind of stuff 241 is much better option in my opinion.

with that I run nothing but 205 tcases and love them . ya low is tad under the rest out there . but being able to twin stick is so nice .
 
10 spline fig 8 from 4 speed . and not original to the 85 he said it was from . tag shows it was made in the mid 70's .

and its a early style yoke c/v head front output. 10 spline .

pass unless dirt cheep for parts to use or resell .

------------------------------------------

you want this setup

pic - 1 = 205 round 6 long input = ONE YOU WANT !
pic - 2 = left long input round 6 / right short input old fig 8 both 32 spline
pic - 3 = 4l80-e to 205 round 6 adaptor . note 2 mounting ear's position centered/ back just a bit . 1 year only way to spot $$$ adaptor .
pic - 4 = short input by its self . you not need this for your style tail shaft length .
pic - 5 = the round 6 adaptor you need . note 2 mounting feet forward of face . this is th400 tranny style.

chevy-np205-transfer-case-1-ton-400-ludlow-ma_11134474.jpg

img_3214-np20532spshortinputshaft.jpg

0624121043b.jpg

$T2eC16dHJIYE9qUcO3l2BRpi!eBtfg~~60_35.jpg

100_2936.JPG
 
The last one is a Ford case, left hand output.

You need an '85+ GM 205 w/ factory short adapter.
 
if smoking deal for any divorced or ford case there good for parts .

32 spline front output . and also fixed yoke rear setups .

but find what you need first .
 
Why do you want a SYE so bad? Are you having troubles with your rear shaft?

Martin
 
82355 said:
Why do you want a SYE so bad? Are you having troubles with your rear shaft?
Click to expand...

No, but with my recent 14bff and ORD spring swap my geometry is all messed up. I'm going to need a new driveshaft anyway, and I'm noticing how much the angle difference would be without the slip yoke. I don't think I'd need shims or perch rewelding at all without it. Plus dealing with the oil pouring out everywhere when the shaft was off reminded me of what a pain that is. A splined shaft seems like such a better solution.

But yeah, I could throw 10 degrees of shims and a new CV slip yoke shaft at it and it would probably be okay, just not as good as it could be.
 
sweetk30 (or anyone else), what year/model did the 205's I want come in?
 
One tons up to 1991, of course "our" body style only. They are relatively hard to find, at least when I was looking.

And I can't recall which but some of the 205's had slip yokes that vintage. Believe the difference was whether the truck had auto hubs or not.

The yoke still isn't going to fix the driveline/CV issue, period.
 
dyeager535 said:
One tons up to 1991, of course "our" body style only. They are relatively hard to find, at least when I was looking.

And I can't recall which but some of the 205's had slip yokes that vintage. Believe the difference was whether the truck had auto hubs or not.

The yoke still isn't going to fix the driveline/CV issue, period.
Click to expand...

After I posted this I found the ORD tech page on 205. If I understood, the short shaft covered part of the time and the long 32 spline input came around 1985. Does that sound right?

You're talking about my angle issues? Yeah, it may not totally solve it, but I think it'd make a big difference, and now is the time to do it before I weld the perches again.
 
All GM NP205's use a slip yoke from 1980-1987 except for crew cabs, I believe.

You need a 1985-1987(1991) NP205 from a K30 crew cab.

Martin
 
Mastiff said:
You're talking about my angle issues? Yeah, it may not totally solve it, but I think it'd make a big difference, and now is the time to do it before I weld the perches again.
Click to expand...

How is it going to make a big difference? Unless you are changing the operating angle of the joint (which will only happen by lengthening the driveshaft significantly, without dropping the case) vibration and joint life are still going to be issues.

I can never keep that spline issue straight. The TH400 output was the same for nearly ever on the 4WD applications IIRC, but you are getting advice to go '85-91, so I'd trust that. I know someone will clarify the shaft issue.
 
but switching to fixed rear gets him a HUGE option list for driveline setups over slip yoke.

85-91 round 6 adaptor style from 1ton . and bonus if from crew cab or stick shift long wheel base truck as it will have fixed yoke rear.

if not its easy to swap over from slip yoke. :thumb:
 
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