New th400 with a few Q's

[mattman4x4]

Hi guys,
I currently have a th400 NP203 set up in my truck. my father-in-law hooked me up with a new th400 and transfer case from an 85 short bed. I am in Salisbury MD, he is in Frederick so I have not seen the T/C. He is planning on bringing it down in a few weeks.
my questions:
1. what transfer case came on an 85?
2. where would I find differences in over all transmission-transfer case length?
3. Is a th400/203 longer or shorter, will I need different drive shafts?

thanks
Matt

 

[sweetk30]

if its all stock i think you will find its not a 400 tranny in a short bed in 85.

prob a 700r4 and 208 case.

 

[mattman4x4]

That is interesting, my Father-in-law is a retired mechanic. He defiantly said it was a 400. Now I am really wondering what transfer case is attached.
thanks
Matt

 

[scrappyk5]

The tranny could have been changed at one time. if that is so, then the th400 your getting could have a 203,205,or a 208 tcase have him take a pic, put it up on the board, we will tell then

 

[mattman4x4]

Thanks, will do!

 

[mattman4x4]

ok, Don (Father-in-law) just called and said it has an aluminum case with two drain ports on the back side. He also said it had a squarish front output(he dose not do digital photos). This would make it a 208? looks like this:
http://www.4x4review.com/Portals/1/OldImages/tech/tCase-spotters-guide/np208.jpg

So now do the 203 and 208 have different spline counts?

 

[BlazerBoyK5]

Your th400 has a 32 spline out put so the 203 will have a 32 spline input.
If the 208 tcase was behind a 700r4 then it will have a 27 spline input. If the 208 was behind a standard it will have the 32 spline input. Ask your father in law that the tcase was behind and then you will be able to figure out what the spline count is without seeing it. But then again i could be wrong bacuse it could have been moded to fit behind something else.

 

[nvrenuf]

Allow me to muddy up the water a little...

I'm not going to say the th400 came in the truck but at some point in the mid/late 80's the th350 was discontinued and the th400 became the "standard equipment" 3spd auto. The th700 was much more common but o/d was an option. I was thinking this change hit around '87 but I've never been able to confirm the year.

 

[BlazerBoyK5]

My 84 came with a 700r4. So that was an option not standard?

 

[nvrenuf]

Overdrive was always an option.

 

[BlazerBoyK5]

I didnt know that. Learn something new everyday.

 

[mattman4x4]

Humm... Chevy always has lots of options!
So now to the major question of drive shafts?
How will I be able to know if I can use my current drive shafts, or find "new" ones from the parts yard?

 

[BlazerBoyK5]

You should be able to reuse the old ones but probably have to have them extended or shortened. I get my done for about 100 bucks a shaft at a locla driveshaft shop. That includes them balanced and new ujoints.

 

[mattman4x4]

I have the feeling that Salisbury probably dose not have a drive shaft shop...Ill have to look around.
Thanks

 

[sweetk30]

look for a big truck parts supply house. like a napa also .

thay sometimes have machine shops in house or drive shaft shop in house.

here we have a cook brothers big truck parts shop with full driveline shop in house and thay make a lot of shafts all the time. and are full spicer dealer.

 

[toomany]

If you're swapping in a 208 in place of a 203, you will need a new rear drive shaft. The 203 has a bolt on yoke, with a slip in the drive shaft. The 208 will have a slip yoke output, needing a solid shaft.

 

[mattman4x4]

My plan was to bolt up the new TH400 and 208 as a unit, since it is getting a rebuild.
My old 400 is on its way out (slipping. leaking,..not shifting well) also the 203 is leaking.
So drive shafts will have to be fiddled with....o.k.