transfer case exchange

[ol yellow 72]

hey guy im looking at swapping my np205 for a np208, anywho i was at pull-a-part over the weekend and they had a nice 87 blazer with a np208 in it but it was hooked to a 700r4, i have a 350 turbo, so my question is, does the transfer case have to come of a th350 or will one off a th400, 700r4, or even a maunal tranny work for me?

also other then the case, the shifter, and the floor hump, what else would i need to swap the 208 inplace of the 205

my rig is a 77 chevy 1/2 ton 4x4

[48cj2a]

Any particular reason you are wanting to go from a HD totally gear drive case to a weaker chain drive case?

The adapters are different as well as the tranny output or T/C input spline count.

Checkout Advanced Adapters or Novak. They explain what transfercases fit what trannys.

If you are going to go for the 208, get the 700R4 also and pickup a 4th gear for the tranny at the same time. At least you benefit from slightly better fuel economy.

You will also need the shifter assembly from the cab and all the linkage for the 208. Probably have to cut a different tranny hump hole as well.

[ol yellow 72]

basically i dont like the idea of being in 4x4 all the time, and i want the fuel economy of being able diesnguage the front end when not needed

[GM72K10]

Originally Posted by ol yellow 72

basically i dont like the idea of being in 4x4 all the time, and i want the fuel economy of being able diesnguage the front end when not needed

You sure you don't have a 203?

[48cj2a]

What he said...the 205 is the part time transfercase. The 203 is the full time. Do you have lockouts on the front axle?

If you have the 203 there is a part time kit you can get that changes the parts in the transfer case to make it part time.

Post a pic of the transfer case.

[ol yellow 72]

guys im sorry u r correct, 203 is what i have and its killing my fuel mileage

[ol yellow 72]

no lockouts on the hubs

[royo]

t350, 700r have 27 spline outputs. th400 is a 32 spline output

[48cj2a]

Now that you have confirmed you have a 203 you have a couple options. But to also benefit fully from this you will also need lockout hubs for the front axle either way you descide.

Option 1: (Most expensive) get the 700R4 with the 208 and probably the crossmember and the driveshafts, remember you need the shifter and linkage and will need to cut a new hole in the hump and patch the old hole as well. (here you will gain some fuel economy from the 4 gear OD transmission).

Option 2: get a part time kit for your transfercase. These are pretty easy to install with basic mechanical skills and will require no mods to the driveshafts or anything other than what parts you swap inside the transfercase. This kit I found with a quick eBay search is one of the most popular and under $45 plus shipping so this is a win win here: http://cgi.ebay.com/ebaymotors/MILE-...Q5fAccessories

Looks like he has the lockouts too for under $70 plus shipping: http://cgi.ebay.com/ebaymotors/MILE-...item45f7532d85

[ol yellow 72]

im pretty confident i can do the transfer case part, but whats involved in making the front end locking hub? i know it cant be as simple as just putting the lockers on

[48cj2a]

Originally Posted by ol yellow 72

im pretty confident i can do the transfer case part, but whats involved in making the front end locking hub? i know it cant be as simple as just putting the lockers on

Actually it is about that simple.

Do yourself a favor and inspect and repack your bearings at the same time.

Layout a shop towel, 6pack box flat, or cardboard and layout the parts as you disassemble.

Once you get the chrome cap off, there is a big snap ring around the edge of the hub and one on the axle. remove the metal gear the ties the axle to the hub, the big tension spring, and the axle nuts n washer.

Remove the hub, remove and repack the inner and outer bearings and repalce the seal. If you remove the 6 nuts that hold the spindle there another caged bearing that should be inspected and repacked inside the spindle.

While you got the spindle out you can actually pull the front axles out and inspect the u-joints and replace if needed.

When you go to put it back together there will be a new part time gear assbly that replaces the big metal one u pulled, and the lockout hub will bolt to that replacing the chrome cap.

[motornut]

Mine was done before i got it
seems to have been done right

[bmchevy1979]

here is a link on how to install the part-time kit in the transfer case http://www.coloradok5.com/milemarkerpt.shtml