Ok, First I have the following,

1986 Pontiac Trans AM 305 with A4 700r4 trans

I have been given a TH400 or Turbo400 if you will, transmission....

I want to put this TH400 in my trans am.... I want to know the following:

1: Additional Parts Needed?

2: Modifications Needed?

3: Any guides/websites outlining the swap available?


I have searched on the board and found various answers and would hope to find a more definate one. Please assist.

The th400 has been rebuilt professionally.

 

TH400 slip yoke and shorter driveshaft
A crossmember since the TH400 rear mount sits back a lot farther.
Some way to attach the torque arm
Electric kickdown

The crossmember and torque arm solution can be done with a Spohn torque arm conversion.

 

Do you have the spohn's part numbers or link?

Thanks for the reply.

 

Click the banner at the top of the page. www.spohn.net

 

Where does this come from and how does it work? A cable won't work? Thanks

 

There's a solenoid in the trans that can be activated by a micro switch on either the throttle linkage at the carb or mounted at the gas pedal(this is how the factory mounts it).
I know TCI and B&M make kits just for this.Others probably do but those are the first that come to mind.You can fab your own too.
Just for curiosity why do you want to switch from the 700R4 to the TH400.Unless you're pushing some very serious power the added weight and power consumption really isn't worth it.The 700 can now be built to be very reliable or use a TH350.And maybe sell the TH400 to cover your cost.

 

700r4 isnt capable of anything, and thats a fact

 

Start with the sticky post up top. It covers everything briefly. It's going to run you more than a couple bucks to get it in and in my opinion, for your application it wouldn't be worth it. Putting a th400 behind a 305 makes almost no sense. Not worth losing overdrive, it's heavier and will suck up more HP before it makes it to the wheels. If I were you I would sell the th400 and buy a stall converter and shift kit for the 700R4.

 

Tony did a great job with his write up. Have a look at the top of the page.