sft3303

So I've found plenty of info for people wanting to swap over to tII transmissions, but what if my n/a transmission is tired and needs to be swapped out, and all I want is another n/a transmission. For an S5 FC (1990 model to be exact), what are my options? Must I stick to s5 trannies? Can I use any FC transmission (i.e. s4 and s5?)? Any n/a 13B transmission (including that one 13B FB trans, but not the rx8, we've been over this)?

On another note, I'm looking to swap over to a turbo II lsd (as my diff is pretty tired too) and so far I have a line on the diff and the halfshafts. I'm assuming I'll need another driveshaft in order to have this work with my N/A setup (good deal, I already need one of those, my U-Joints are pretty worn)? Am I missing anything else here?

Thanks for all the help guys, if I just looked over something stupidly, it'd be awesome if someone could just point me in the right direction to whatever page or something that I missed.

DaBrkddy

I have swapped an S3 13B trans out of a GSL-SE into my '88 GXL, and I've also swapped a '90 S5 N/A manual trans into an auto '88 GXL. Both are still running and driving (I now own both of these cars.)

From what I remember, the FB trans went into the GXL without too much of a fuss. Basic drilling/filing skills will be necessary here. Stock FC driveshaft works with this trans swap, you will have to splice wires, and the stock FB shifter works best. Second gear synchro in the FB trans is smaller, so it wont last as long.

Don't quote me. Take this with a grain of salt: I believe the "Type M" gear box used in one form or another from '84 to '91 in the N/A cars is RELATIVELY the same gear box, with minor changes/improvements through the above years. Among these were: Changed shifter pedestal location from FB to FC, changed Synchro diameter, Changed mounting size/ location on tail housing, and changed wire connectors. I believe similar changes were made from S4 to S5, but I don't think the changes were as drastic.

I will say it again in different words: Don't hold me responsible, you're on your own.

as for the rear diff, you're probably going to have to at least have a custom drive shaft fabbed up. I'm also not sure on the rear hub spline fitment between the N/A and turbo cars.

Good luck. That's all I have to say.

Derekcat

iTrader: (8)

If it's a factory Manual car, you can use any S4/5 transmission so long as you have the matching Y/T-bracket and crossmember [the S5 has a Y-bracket that bolts diagonally to the trans, S4 is more of a T that bolts vertically -- the crossmembers again only work with the matching bracket/transmission]

You CAN use an NA driveshaft with your T2 diff, I helped a friend do this:
Take the rear flange of the NA driveshaft and press it against the input flange of the T2 diff, rotate so you're ~45deg off from the turbo driveshaft holes... Make your marks and drill. Simple as that [you may have to rotate the flange to drill without damaging the neck of the diff]

sft3303

I wouldn't hold anyone here responsible for my own work, no worries. That's common sense.

However, it looks like there are some different mounting brackets and shifter issues I'd be running into? Even if the transmission basically bolted up the same? So I'd guess my best bet would be to go to another s5 transmission?

For the recored, it is a factory manual n/a s5 car. I just want to replace the old, tired, 220k mile 5 speed.

sft3303

I'm also looking at the diff swap. aside from the diff itself, I will only be needing the driveshaft and halfshafts? Does anyone with experience want to chime in here? I have heard of people doing this, but I'm a bit fuzzy with the details (i.e., he used the halfshafts from the LSD but also had to transfer over the hubs b/c the splines didn't match up or whatever, idk)

Thanks so much guys

Derekcat

iTrader: (8)

It'll be fine if you find an S4 transmission with the bracket and crossmember [about half the time I see people include them].. Aside from the mounting difference, I think the only S5 change was a *slight* gear ratio change for 5th.

You'd need the halfshafts, but not the drive shaft [per my previous post].
I don't know if any other halfshafts fit, but I know the T2 ones will slide right into the non-turbo hubs.

sft3303

Awesome, that helps. Broadens my choices.


Sorry I missed that, but thanks for following up! Sounds like it'll work great for me.

wvumtnbkr

If you are going to all this trouble, why not put in a TII trans also? That way you are only an engine swap away from a full TII drivetrain.

The TII trans are MUCH stronger.

texFCturboII

iTrader: (17)

Why? If you aren't looking to swap in a turbo engine and aren't modifying your N/A to ridiculous levels the N/A transmission works fantastic without having to go through the trouble and COST to source:

Decent T2 transmission: $250
T2 clutch: $60
T2 flywheel: $100
T2 slave cylinder: $40
Special T2 transmission to N/A Differential Driveshaft: $180

Total cost: $630

OR

Decent N/A transmission: $150

texFCturboII

iTrader: (17)

Nevermind.... didn't read well.... Unless you are swapping over a T2 transmission then it will be difficult to JUST swap the differential. I don't think the N/A driveshaft will work and I don't know of anyone who sells a reverse N/A to T2 driveshaft.

Why not just source a LSD differential off of a S4 GXL and call it a day?

Derekcat

iTrader: (8)

As I've said twice, it will work. I helped do it to a friend's car.

The issue you normally run into is that the rear flange [the flat piece on the rear end of the driveshaft] is smaller on the NA driveshafts. Carefully lining it up on the input flange of the T2 trans and marking/drilling out the holes works fine.

But yes, finding a real NA LSD would be MUCH easier. Sometimes the halfshafts are very stubborn to remove...

texFCturboII

iTrader: (17)

Sorry to sound rude, but that sounds like a ghetto *** fix! If it works, it works I guess; I've definitely done my share of ghetto fixes! I'd worry that I'd mess up the holes without using a proper press and that rotating mass being off balance would put unnecessary stress on the gears?

sft3303

Mazdatrix sells a driveshaft just for this. Non turbo tranny in non turbo car with turbo diff. I needed new u-joints (and a lot of other things) so this may just go in at the same time...

Derekcat

iTrader: (8)

No worries! If I remember the details correctly we cut a flange off of a bad driveshaft and held it up against the diff input shaft and the centering ring was the same size, so all we had to do was not twist it while marking the holes. He never had any trouble with it.. Probably ran 9 months or so before a coolant seal went in the engine and he parted it out.


sft3303 >> Yep! That is certainly easier, and with replaceable joints as a bonus, it's probably the best solution for you.

I just wanted to emphasis that you can do this with the NA shaft, for any future searches