Sorry for posting such a noob question but it's been a while since I've had an FC and I've forgotten things

Came across on for sale a S4 with bad tranny and I happen to have an S5 tranny/starter/driveshaft/LSD rear end laying around and was wondering if it's bolt-on with what I have or would I also need S5 flywheel/clutch?

(oh, manual transmission btw)

 

i think you need the s5 counterweight, correct me if i'm wrong

 

Naw, you gotta put the Miata tranny in.

 

OK:

are both cars in question TII's?

if yes, then you can leave the flywheel on the S4 and just use all the other S5 parts (tranny, driveshaft, rear end)

If no, then no.

edit: "nah you gotta put the miata tranny in" - eatmyclutch

Sorry dude, but I have yet to see you post useful information.........just something you might want to think about....or not, whateva.

 

The NA Transmissions swap over with no changes needed.
While you are down there, you could swap in your driveshaft and lsd if they are in better shape

 

Ok, let me say it differently.

S4 and S5 NA tranny's swap out straight across. The only exceptioni is you need a S5 Tranny mount for a S5 tranny, a S4 tranny mount for a S4 tranny.

S4 and S5 TII trannys swap out straight across, albeit with the same tranny mount conversation. And, TII tranny mounts are different part numbers than NA tranny mounts.

You can put a TII tranny (regardless if s4 or S5) into a NA (regardless if S4 or S5), but will need all the TII things that go with it like clutch, starter, flywheel, clutch slave cylinder, and the custom drive axle that Mazdatrix sells.

Same thing for putting a NA tranny into a TII with the same additional parts. But few would advise doing this, my self included.

In all cases, you don't have to worry about the rear counter weight if you already have an aftermarket aluminum or lightened steel flywheel. Again, the NA and TII flywheels are different as well