subaru WRX 5 speed transmission input shaft question?

Question

I have a subaru WRX 5 speed transmission with 1st gear broken (a tooth came out the drain plug).
I got the transmission out of the WRX last night and I have an extra subaru transmission from a non WRX model that was a similar year (I never actually saw the car it came from, it was sold to me as a WRX transmission, but it has a push type clutch, so it will not fit my car).

anyone know if the input shaft from my WRX will fit on another random subaru gearset ? or what are the chances ?
I am going to take it apart tonight to see,

anyone see a down side to saving money by not getting the original parts ?

also, anyone know if you really have to replace the thrust washer that the service books say that you have to replace every time you take the transmission apart ?

Answer 1

Hi. Look I'm not certain but as you're not getting any other answers and I'm a Rex nut (former owner and near future owner) I'll answer anyway.



I would think it would be risky in the long run, particularly if you have worked the Rex at all. The WRX pulls about 300 Nm of torque and the RX pulls about 150 with a caravan pushing it down a hill. If you've worked the Rex it might pull up to 400! There'd be a fair risk I would reckon of shredding the gearbox when you least want it - in a race, up a winding mountain in the night time etc.



If there's no other damage inside the box, pull it apart and replace first gear. Not THAT hard - just make sure you have any required tools and an accurate torque wrench ... and you label every part!



I suspect Subaru may have even deliberately made them not fit. I would also think most of the Subaru dealer service people gush when they're talking about WRX's so you could go and have a chat to them. They'll probably tell you what's involved in replacing a gear - they would have rally drivers asking this all the time!



Thrust washers are cheap and fairly important. Do it!

Answer 2

If you have the transmission apart already, I think it is a good idea to purchase the correct replacement part so you don't have to crack open the transmission again.



I think a great idea would be to purchase replacement WRX gears (make sure they are for a late '03-'05 5spd transmission, because the gear width was increase compared to the '02 and early '03 transmission) and get them shot peened for strength. The parts might cost a bit more up front, but you will have a stronger transmission you won't have to worry as much about down the road.



1st, 2nd and 3rd are heavily stressed gears, so I don't think it is a good idea to cut corners when replacing those gears

Answer 3

Ppg Gears Wrx

Answer 4

Hey, instead of getting the stock gears, try the legacy GT gears. Should be the same price as stock gears and they are stronger. From what I read, they are the same as the jdm sti non-ra. Do a search on nasioc, a number of people have done it and are very happy. Good luck!

Answer 5

It appears as though money is not a factor for you.... If thats the case, go with the 6 speed STi swap. Better gears, stronger tranny, and its a 6 speed!