NP205 to 700R4

[K5dreamer]

Hey all, im lookin to swap a 4x4 700R4 into a 72 blazer with the NP205 transfer case to get the overdrive gear. anyone know what imma need to do that swap? do they bolt right up or am i going to need some sort of adapter?

thanks in advance for any tips.

 

[jekbrown]

you'll need a factory th350-to-np205 adapter + the ~2" spacer. I used one with my 700 for years, worked great. They are around $60. I forget the part #, but if you search, its out there.

j

 

[Cricket]

You might check with advance adapters: http://www.advanceadapters.com/ As far as I know there was never a 700 to 205 from the factory.

Ooop, looks like Jek answered your question.

 

[chosen(1)]

you'll need a factory th350-to-np205 adapter + the ~2" spacer. I used one with my 700 for years, worked great. They are around $60. I forget the part #, but if you search, its out there.

j

Which 205 do you need?

 

[4X4HIGH]

Would need to be a 27 spline 205 from behind a TH350.

 

[jekbrown]

yeah, what he said... sorry I forgot about that part. On the plus side, th350-version 205s are common and cheap.

j

 

[gmc4cw]

If you buy a klune-v underdrive it will work as the adapter and give you another gear to choose. They are expensive though. But any input spline to any output spline is nice with a choice of ratios.

 

[K5dreamer]

ok well the truck already has the th350 and np205 transfer case, so i guess i just gotta find that 2in spacer.

second question, does this swap create any drivetrain angle problems or driveshaft length issues??

i plan on putting a 4in suspension lift on the truck sometime down the road, would that complicate the swap?

thanks again

 

[bigblock72]

There are two options to adapt, the 2 inch spacer mentioned (usually found on 80s 350/208 combos) or get a short output shaft for the 700r4.
This swap (especially if you use the spacer) will actually help the front drive line because it will be longer and will keep the u-joint angles liveable. I would recommend using a CV on the rear driveshaft to keep the angles and vibrations down to a minimum.

 

[4X4HIGH]

ok well the truck already has the th350 and np205 transfer case, so i guess i just gotta find that 2in spacer.

second question, does this swap create any drivetrain angle problems or driveshaft length issues??

i plan on putting a 4in suspension lift on the truck sometime down the road, would that complicate the swap?

thanks again

You will need to lengthen the front shaft and shorten the rear shaft. The 700R4 is 1 7/8" longer than a TH350 and then you'll be adding a 2" spacer so you're going to be about 4" longer than your existing TH350/205. Driveshaft angle on the rear will be a problem that you will need to address right away or else you'll be getting a bad vibe. I would definately run a CV rear shaft.

 

[K5dreamer]

good to know guys, thanks.

you mention the CV rear shaft link. is that something i can just google, or do you reccomend a specific source for that part? also is it hard to install? i have an air compressor and probly most automotive tools nessesary, however i do not have a welder, and am not really experienced at the task. would this CV joint install be a bolt in process?

 

[bigblock72]

You will have to have the driveshaft built the correct length with a CV (basicly two u-joints right next to each other allows higher operating angles, most front driveshafts use a cv on the front shaft on the t-case end.) You will have to change the yoke on the transfer case to correspond with the CV. So basicly once the shaft is built it is a simple bolt on deal.