700r4/205 ??????

[blueblaze]

Okay! Here's the deal... I have a SM465/Np208 setup right now. I'm a little sick of the stick. I thought about it and deiced to go with the 700r4/Np205. Now the question... What can I do to make it as easy as possible? What year should the truck/blazer be for the part's? As anyone done this conversion?

 

[jekbrown]

I dont think K5s ever came with the 700R4/np205 combo. Dunno about trucks....

j

 

[Hossbaby50]

That combo was never offered that I am aware of. Several people have done that swap though. From what I understand you need find a specific 205 (I believe round bolt pattern) and you have to cut about 1" off you tailshaft on the 700R4 to do it.

This is what I am thinking, but I am not 100% on any of it.

 

[outlaw612]

Do a search, this has been covered many times. It can and has been done.

 

[doctor4x4]

and please just buy the right out put shaft from advance adapters its only like 125.00 not cut your old 1 if your gonna run big tires or really off road it

 

[jekbrown]

yeah, never cut that much off a tranny output shaft unless you have some pimpin way to respline it etc. I have a 205 behind a 700r4. I mounted it using the 205s original th350 adapter plus a 2" spacer (part # is out there, do a search). This spacer only requires that you trim 1/8" or so off the shaft, which is really insignificant. The spacer only costs $50 or so, and unlike the new output shaft from AA, you wont have to tear your tranny ALL the way down to do the install...

j

 

[bigjbear]

And be prepared to loose a lot of gear reduction. If you're having case trouble put a 205 behind the 465. If you just want to ditch the standard use the 208 or 241 behind the 700R4.
Just my $.02, I've got a TH350/NP205 & 4.56 gears and it sucks big time for reduction. The differance in my buds truck w/ TH700R4/NP241 & 4.88 gears (that were to low for me w/o O/D) is amazing. Both are on 35s.

 

[jekbrown]

the 205 doesnt have the best low range... but I'd never recommend swapping in a tcase that has a slip yoke on a off-road vehicle. the design just sux.

j

 

[bigjbear]

You mean one like the '80 & up NP205?

 

[jekbrown]

dont get a 1980 205, they have slip yokes. /forums/images/graemlins/confused.gif what you need is a np205 that was from the factory behind a th350, not sure which years they came on. I think in webshots I have a pic of the factory adaptor though so it'd be pretty easy to pick out in a yard. Here is a pic...

http://community.webshots.com/photo/63209924/63211011btRBAb

yep, thats the one. The adapter is the big thingy on the top/right of the photo that has the shifter bolted to the top/left side of it as well as the input shaft deal (round thingy to the right of the shifter) and the mounting part (below the input with the 2 big holes in it for mounting to an x-member). Anyway, this is the np205 you wanna look for... its the easiest to get behind a 700r4. Once you have one of these, all you need is one of them aluminum spacer things and your are set.

btw, another good mod to do while you have your np205 out of your rig is the front-output-shaft swap, especially if the np205 ya have has a 10-spline front output. I got a 32-spline one from a furd np205 and swapped it in myself. Its not that hard and a tech article (think its posted here at ck5) helps a lot.

j

 

[bigjbear]

All I wanted to point out was that just getting a 205 doesn't net you a fixed rear output. The 27 spline 205s w/ a fixed rear used the figure-8 mounting pattern, while the 208s & 241s that came behind the 700R4 used the round pattern. This is nothing that can't be overcome but it add a little more compilaction. Just from looking at the parts it seems that it would be easier to use the newer 205, assuming that is what you realy want, and swap outputs. As far as the 241 goes you can swap a fixed output on to it as well. I thought you could do the same w/ the 208 using Dodge parts, but the last time I tried to find the info/part #s I had no luck.
No matter what 205 he uses it will be a big difference between ~ 17:1 and ~ 6:1 out of the case. I just wanted to throw that out there. I agree w/ you on the slip yoke, in fact that and 2WD Lo are why I like the 203 in my '73 better than the 205 in my '80. As always, YMMV.