Im going to need a transmission rebuild soon and was wondering if anybody knew of any rebuild kit for the s4 n/a 5-speed transmission? I know everyone says to swap to the turbo transmission but I unfortunately don't have money for the whole swap.

Any help pointing me in the right direction would be greatly appreciated!

 

you can find kits on ebay and such. Mazda sells all the parts separately.
if you are doing to try this yourself you need a puller with really long fingers,

Mazda's were just a bar with the an end thing bolted on, so its pretty straightforward.

you also want a bench vice, to hold the center plate, and then a nice clean place to lay out all of the parts in order where they won't get disturbed.
there are a lot of little bits in there, and they all need to go back in exactly right or it won't work.

 

all you can do is rely on the reputation of the parts supplied, some aftermarket synchros may not hold up as well as OEM(OEM is Bronze some of these kits use brass because its cheaper to produce and also less durable, brass has a near golden yellow appearance, bronze looks dirty and aged) but they cost a fraction of the price. many suppliers of aftermarket kits use Nachi/NTN bearings which are mostly what the OEM uses, the seals may be supplied by various companies and have varying results, i have no idea how well a timken seal would hold up for example.

would i risk it? probably, because the difference of parting out an OEM kit is the difference of $200 for aftermarket versus nearly $1k for an OEM set.

I'm actually going through this right now since i have an ex customer who needs an FD transmission overhauled and pricing out various suppliers. most likely i'll use an aftermarket bearing kit and replace the needed synchros with OEM(FD costs $600 for a set of synchros FYI, mostly due to the double cone synchros which the n/a doesn't have).

some synchros in brass is fine, the FD uses a brass 5th gear synchro, it is also why when you miss a 3rd gear shift and go into 5th it cracks, however it appears mazda never rectified the potential shift issue fault with a true material revision(however i didn't pay close enough attention last time i did one, the stock photos i see of it online are brass. it has had 3 revisions so i could be wrong). though that is a turbo transmission issue, not an n/a one, the engineers never anticipated someone trying to bang into 5th though it happens quite often and with a very wrong RPM match speed(2nd to 5th).

with the lesson over, basically if you don't beat the snot out of your car the aftermarket kits should be fine, if you do drive it hard occasionally or often the OEM bronze synchros are pretty much a need. do the synchros really need to be replaced? it depends on how the car was driven and how hard, and what fault the transmission is being rebuilt for. there is specs in the service manual for synchro wear, if the teeth are mangled too, time to toss 'em.