Swapping out 700R4 to TH400?

[BruceLopesJr]

OK, so I bought an 84' GMC Sierra (70K original miles) with the 305/700R4 drivetrain to start my plowing business.  I have a new rebuilt left over TH400 out of an 80-something Blazer that is just laying around.  

Since I'm sure the 700R4 will tire after a season or two of plowing (I'm adding a deep trans pan, synthetic fluid, and cooler this year) what would it take to put in the TH400?  

I'm assuming the driveshaft is a different length and the splines are different too?  How about the ability of the TH400 to mate with the stock transfer case?  

Just trying to figure out whether it would be easier to buy a better 700R4 or swap out what I have.

Thanks

[BruceLopesJr]

So nobody knows anything.........

[roundedline]

It is a different spline count for the 700R4 vs TH400.  You won't be able to use the factory transfer.  If you had the matching transfer case with the TH400 it would be a bolt in except for the driveshafts.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[BruceLopesJr]

Thanks for the info.

[Blazin]

Bruce do you have a relative Rick Lopes from N.H.?

[BruceLopesJr]

Not as far as I know, but we're all related somehow.    

[Blazin]

Yeh we are, I was just curious because Lopes is not a common name.

[BruceLopesJr]

All depends where you're from.  There's plenty of Lopes' down here.  Very few of which are related to me.

There is a very high percentage of Portuguese families here, with Fall River pretty much the center of it all.  Some refer to it as "Little Portugal".