When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Recently my 03 wrx has started making a whirring noise and without going into the whirry details, i've taken it to a gearbox and axle specialist and theyre 100% sure its the transfer box causing the noise after taking it for a road test. This is a very good result for me as I took it to a normal garage originally and they said i needed a new gearbox / gearbox rebuild so i'm quids in for a transfer box.
I have however also had a bit of difficulty getting into reverse and first, although this has been for a few months and much longer than i've had the noise issues. I'd say around every 100 miles or so worth of driving, it'll be a pain to get into reverse from standstill and when it plays up i normally just cycle through the gears and manage to get into reverse, annoying but not the end of the world. My old leggy was like this sometimes as well. A lot less frequently, say around every 500 miles of driving, first gear will do the same to me and has on a couple of occasions spat going into first.
Unfortunately I have to wait until 1st sepetmeber before they can fix it but just had a couple of queries on tranfer boxes and transmission in general. My car has done 96k, blobeye wrx and has been mapped at 280bhp so above standard but not silly power.
From my very limited knowledge of transmission, i'm guessing the gear issue is completely unrelated to the transfer box and that a knacleered transfer box will have no affect on getting into gear at a standstill?
To change the transfer box, will all the gearbox oil have to be drained out and replaced? If so is there any hope this might also solve the shifting issues?
I've had a bit of a look at various stuff to see what could be causing the shifting issues and it seems synchros and clutch not releasing properly are the most likely culprits. I'm hoping that the transfer box replacement and a full oil change on the gearbox may resolve the shifting issues, I'm guessing not but will be very happy if someone could tell me otherwise lol.
You need to ask what the specialist means by the 'transfer box' because Impreza's don't have a transfer box; the gearbox houses the normal gears (1-5 + R), the centre and front differentials in one casing with the rear diff connected via a prop shaft.
5 speeds do have a known issue with failing and most people just swap the gearbox.
Ah right, good start lol. Yeah i'm not sure, the noise sounds like its coming from infront of the dash if that makes sense (so closer to front of the car) so I would guess front and centre but not 100%. They said they can change it without having to take the box out if that helps.
The TAIL casing houses 5th and the centre diff in Don's last picture that is 5th gear and the bearings that Don has highlighted are in that casing that has been removed.
Last edited by 1509joe; 16 August 2021 at 08:54 PM.
Ah right, thanks a lot for the detailed response. Yeah the noise only came on after driving for a bit so when the gearbox was warmed up but it pretty much makes a noise straight away now.
Hopefully it will be something like a gear nut worked loose causing the shifting issues, the shifting problems aren't THAT bad, just enough to be annoying so it would be a huge plus if the work I'm getting done happens to resolve that.
The guys I took it too seemed fairly clued up, I could actually smell gearbox oil from the car park lol. They had loads of gearboxes and axles and stuff lying around and they seem really busy so obviously got a good reputation.
I had a bit of a nightmare finding a garage that would even look at the car, nobody wants to touch a scooby lol. This garage says they specialise in jap and European import gearboxes which is why I tried them after phoning a load of local gearbox places with no luck.
So if i'm looking at those diagrams correctly, the 5th gear nut on the main shaft needs to be removed anyway to replace the front transfer bearing? I'm presuming they would be replacing both the front and rear transfer bearings or would have at least quoted me for that (£500 plus vat).
EDIT: Sorry just re-read and looked again and can see the 5th gear nut is behind the front transfer bearing, would this be revealed when they remove the bearing or would there be further work involved to get at the 5th gear nut?
5th gear nut is looking at you when you remove the tail casing. The five speed tail casings are 99% interchangeable you just have to watch your drop gears are correct.
You should find more than enough info in this and it's linked threads.
As said the transfer case and extension can be removed and bearings replaced while box is still in the car.
16 August 2021, 03:24 PM
Potentially dumb transfer box questions 03 wrx
