So I have the following waiting to swap out my dying auto trans:

- S4 NA Manual Trans + subframe (cross member?)
- S4 Driveshaft
- S4 Differential
- S4 Flywheel
- S4 Manual pedal assembly
- I know I need a clutch, what do you guys recommend?
[all of this is from a donor S4 [1986] with no motor]

The car that I'm swapping it into is an S5 NA automatic car. What other parts do I need? ECU?

 

swapping an s4 manual trans to an S5 auto car.

#1 is you will have to figure out Mounts on the chassis as the car is not set up for a Manual trans.(Fabrication)
s4 ManualTrans.
s4 manual Trans cross member
S FIVE Flywheel..(it has to be engine specific not Transmission specific,so if you got an s5 engine in the car then you need the flywheel for that engine,which would be S5.)
Manual starter.
Clutch pedal assembly
Master and N/A slave for the N/A trans with respective hydraulic hoses.
Clutch and Pressure plate..
Throw out bearing for Trans.

and some people will overlook this But it is Important...PILOT BEARING..(the auto trans setup does not have one in the eccentric shaft..BUT the Manual setup needs one!)

Only thing I can't say with 100% certainty is the Driveshaft..But I am assuming so,since the Auto shaft is about 1 inch shorter.

 

You will need to make a custom mount for the transmission because the manual cars and auto cars have the bolt holes for the cross member in different locations. You will also need a master and slave cylinder for your clutch. Make sure you use the speed sensor thats installed in the manual trans if you plan on using the s4 differential otherwise your speedometer will be off. Also if you want your cruise control to work after the swap you will need to remove pins j and g from the cruise control computer connector. Note however that if you are using the cruise control and you push in the clutch the engine will go to redline because there is no clutch kill switch (unless you connect one up). Other then that it looks like you have everything, I did my swap 9 months ago and the hardest part is definitely swapping the pedals, you will have to remove your steering column... I recommend removing your drivers seat as well. As for a clutch, if you decide to stick OEM you cant go wrong with Exedy. Good Luck!

 

What about the ECUs? Is there a difference between the manual and auto like in the FD? And is there a difference in transmission harnesses for things like the neutral safety and reverse lights to work?

 

Im not sure if there is a difference between the ECUs but all I did was unplug the automatic transmission computer and left my ECU alone. I didnt hook up a neutral safety switch but you can if you want, and for the reverse lights you have to do some custom wiring which is explained in a write up on the archives.

 

there is no difference in the ECU.

 

Couldn't you just use a switch to turn on/off the reverse lights?

Also, does anyone know exactly what needs to be fabricated for the mounts?

So the auto diff should work just fine, correct?

My auto does not have cruise control, but the S4 does. Does that mean it will swap right in?