STi Version 3 gearbox into WRX Version 2 - Possible?
 

Dear All,

Newbie here.

I just bought a MY94 WRX and the gearbox went to heaven...Someone has STi version 3 gearbox lying around (without dive shaft and rear diff) and i want to get it...

Is the STi version 3 gearbox compatible with the normal WRX Version 2 engine, chassis, drive shafts and rear diffs?

I know the one with DCCD probably not compatible, but without DCCD...is it compatible?

Thanks!!!

Andy

Should be a straight swap m8, the sti box will have closer ratios aswell, making for faster acceleration through the gears, always a good thing!

but i've heard of issues on mismatched final drives for front and rear, non fitting prop shaft...bolting it on should not be a problem, but matching the ratios/final drives...???

Tread carefully.

Best to get the rear diff with the box. My Sti v3 trans is a 4.44 ratio, you must get the right rear diff.

The Sti v3 box is a real delight to drive, short ratios but not RA short, and a fab short shift throw. Tough too.

According to my book, the 1994 WRX has a 4.111 rear diff. Thus you need thie 4.444 diff for the box.

Call David at www.apiengines.co.uk and he may have one.

A worthwlile conversion, will enhance the car and its fun-factor by a zillion % :D

911 :norty:

i would stay with the 4.111 front and rear diffs and use the sti gearbox but thats just me :)

I have had the same problem a few months back..my box went with a bang..i have a 95 WRX , got hold of a STI box and diff from a 97 model and fits a treat... seems to be a far better box than the wrx .. but dont mix gearbox and diffs..have to be the same or you will be back to square one with another blown box :-)

i know for a fact that mismatching the rear and front diffs will result in the diffs grinding themselves to death very soon...


911,
you put it as the only way to do it is to install the matching rear diff with the gearbox. and the normal MY94 WRX rear diff is not a match for the STi ver3 gearbox...so i cannot do just a plain replacement of just the gearbox...can you confirm this?

is there anything that can be taken out of the ver2 gearbox and put inside the STi ver3 (like centre diff, etc...) to make it match the normal wrx rear diff?

Andy:

To fit the Sti v3 (4.444) box 'as is' is hard work, but simple. You will have a very nice box to drive.
To get and change the diff to 4.444 is just an extention of the work you do. I changed mine in 6 hours. It is just a lot of 8mm bolts seemingly every where and releasing the rear suspension on both sides.

I once fitted an RA trans, 4.111, to my car, inc rear diff, so i've done it!

The propshaft is the same and apart from some fresh oil in both parts, just hard labour.

If you are not in a position to do it yourself, any good general garage will do it for you, all a bit of Meccano to be honest.

If you start splitting boxes and trying to match the front diff of the existing box to the Sti gears etc you will have grief all the way as I believe it is NOT Meccano if you do that!

Keep it simple. Buy the Sti box, get a matching diff for £250, some oil, some beer, and friend(s) you can trust. Working hard you can do the conversion over a friday afternoon/sat/sun and go to work (faster) on the monday!

Good luck,

911 :D

in my opinion the sti box is too close for a 7000rpm rev limit, thats why i would use the 4.111 diffs instead of the 4.444's in a v2 wrx

i have an sti RA gear set in my car and mine is a UK car so it can be done :)

steve, you are using 3.9 diffs though ain't you?

the box was split and my front diff was used :) so im still on uk diffs, if thats the 3.9 then yes

fairly straight froward job to open the v.3 box up and check/replace the front diff. (if indeed it has a 4.44) with the 4.11..............

alyn - asperformance.com

You'll probably have to change the Speedo drives over as well, IIRC the STi 3 has an electronic speedo sender, and the MY94 WRX mechancial...they should swap straight over though between the gearboxes.

Good point about the rev limit! My Sti runs 8400 rpm.
The car also has mech speedo drive, its a MY96 'P' reg.
So much for keeping it simple!
My experiment with a 94 RA trans had a set of 4.111 diffs, but was a killer on any road where you ran 70+ for over 20 mins....
911.

Re: Checkengine light issue! Code 33. Speed sensor error.
 

Been fixing up a 95 wrx wagon, I purchased it as is thru a m8 on impulse. So never had a chance to talk to the person responsible for my nightmare.
However its had an engine upgrade along with ecu & wiring loom. Which would all be fine if they had used the gearbox to match the newer power plant! Here's the problem. Original gearbox has the manual speed cable where the newer V4 has the electronic equivalent. So after replacing the cable with no joy i came to the conclusion the Ecu needs that signal..
Anyone know a way to trick the ecu into thinking there is no issue? Or like i read above can the Speedo drives be swapped from mechanical to an electronic one. Obviously would need to change my dash cluster also to match. .