72 4x4 transmission

[Lake bums]

Im needing help , will a 400 turbo work in a 4x4 truck that I'm building . It has a 402 engine.

[mechanicalman]

Originally Posted by Lake bums

Im needing help , will a 400 turbo work in a 4x4 truck that I'm building . It has a 402 engine.

What transmission do you have now?

Consider the dimension from the bell housing flange on the engine to the rear of the transmission where the transfer case adaptor bolts on. If you can move the engine that far forward then that would be the easiest way, IMO. You would need a new transfer case adaptor as the T400 takes 6 tail housing bolts and the T350 takes 4, and consider that it might be different dimensions lengthwise and might have an influence on the position of the engine. Not sure about the NP 4 speed.
You can move the transfer case back, but that requires a lot of fabrication to the linkage system, both new drive-shafts, and probably more.

I believe a 700R4 might be an easier swap. Or just use a T350 with HD parts.
See the diagram below for Hydramatic dimensions.

[mrein3]

Originally Posted by Lake bums

Im needing help , will a 400 turbo work in a 4x4 truck that I'm building . It has a 402 engine.

Only with the correct adapter and correct transfer case.

I'm only referring to GM built trucks from 1967 through 1972 that came with a NP-205 transfer case. I have no experience with other transfer cases.

For whatever reason, GM built all manual transmission trucks with a 10-spline output shaft and mated them to a 10-spline input shaft in the transfer case.

The automatic 4x4s all had TH-350s. They have a 28-spline output shaft and are mated to a 28-spline input shaft through an adapter that is different than the manual tranny adapters.

Some time after 1972 GM started offering TH-400s in 4x4s. These have 32-spline output shafts and mate to a 32-spline input shaft on the NP-205.

So to answer your question:
YES. A TH-400 will work as long as you have the correct adapter and transfer case.

[57taskforce]

Don't forget the bigger input bearing on the turbo 400 205. Meaning it's not as easy as swapping the T400 input shaft, into a non T400 205. The non T400 205 case can be machined to accept the bigger T400 205 bearing however, to allow the use of the T400 input shaft.

[Nitis]

I don't see a quick and easy fix here. You're going to be fabricating something and I assume you know this since these trucks didn't come with a big block in 4x4s

So you are either dropping a big block I one or making a 2 wheeler a 4x. Lots a custom fitting for sure.

[mechanicalman]

Originally Posted by Lake bums

Im needing help , will a 400 turbo work in a 4x4 truck that I'm building . It has a 402 engine.

TCI claims to have a kit to put a 27 spline 4x4 output shaft into a turbo 400.


Comment: Want to put a T400 in place of a T350 in a 4x4. Need a 27 spline 4x4 style output shaft for the T400 to fit my transfer case.


On 10/8/2014 5:52 AM, TCI Technical Support wrote:
> Here is the trans for your application
>
> 211100 $1200.00 TCI Th400 with the correct output shaft for the TH350

No, just need the 27 spline 4x4 output shaft. Already have a transmission. Can you provide the shaft?

On 10/8/2014 12:15 PM, TCI Technical Support wrote:
> Here is the kit for the swap 229900 It is $279.91 for the kit

I believe you will still need the 6 bolt T400 adaptor but this should make the output shaft fit the transfer case.

Or, put a new 32 spline input shaft into the transfer case. Raise the bridge, or lower the water.