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Blown Tranny

2K views 9 replies 7 participants last post by  jkimb01c 
#1 ·
Hey guys I have an 04 subaru impreza wrx with 335awhp 5 spd. I was going first to second pretty fast and it kinda popped in and it got stuck until I turned the car off. Then I had to kinda force it out. It won't go into first second or third. Also when I start the car it idles fine I just can't release the clutch or it stalls itself. Can anyone help me? :/
 
#2 ·
Sounds like you warped some teeth on your selector gear and a few other gears as well, unfortunately this means you'll have to replace a few gears if this is the case, the reason why multiple gears as well as it being stuck is happening is most likely because the selector can no longer slide freely. This is generally what happens when you force a gear before the synchronize is synchronized.
 
#6 ·
On a more serious note.. so you're sure 1-3 don't work, but 4, 5, R, and your clutch are still working fine? At first, I would say you broke the shift fork, but 1 and 2 use one fork, and 3 and 4 use a different fork.. although it's entirely possible you broke the fork for 2nd gear, then that piece floated around and jammed up something else.

Whatever the case, if you're sure this isn't a clutch problem, then you're probably going to need to drop the transmission and open it up to see what's going on. Although if you drive the car hard it's probably just time for an upgrade.. At which point it may not even be worth investigating what went wrong with the old transmission, just swap it out with a six speed, or built 5mt.
 
#7 ·
I have a question in would you know about converting a 04 WRX with a 5MT to a 6MT?

I'm new to the Sub'e world, have this 04 WRX with a blown 5MT trany and my son telling me, that the car can be converted to a 6MT, but me being a HD Mechanic. I'm wondering why it wouldn't be able to directly bolt on and what's with all the talk about having swap the drivelines & the rear pumpkin.

And why do the drive shafts have to be changed out when this is done, because the spline differently or the bores bigger? And why the rear pumpkin as well?
 
#8 ·
It is a direct bolt-on, but you have to remember the components are different.

The STi has different half-shafts and hubs, so you have to deal with that conversion. Second, the STi 6MT is physically larger and the R180 rear differential in the STi is larger than the R160 in the WRX. Therefore the prop shaft isn't a direct carry-over. Luckily, the 4EAT prop shaft is just the perfect length to connect the STi transmission to the R160 :)
 
#9 · (Edited)
So you would have to change up the front wheel hubs as well (if understood what you said, because the front driveshafts (which you call "half shafts") are physically different from the STI to the WRX)?
If the R180 (out of the STI) is larger, does this not effect the available room inside the rear differential housing for it to fit inside if the R160 (in the WRX) is smaller?
In last sentence your saying the rear driveshaft (what you call a "prop shaft")(4EAT) would work if you kept using the R160 differential?
The other question is, it would probably fail when all the other components have been up graded and with the amount of horsepower & torque (meaning he's (my son) got this car rod'd right to the nines) would go through it, correct?
Sorry if I'm repeating what you mention in your blog. But I just want to fully understand what's all involved in this Change Up (or 6MT Conversion).

And last thing come to mind; if I went with the idea of up grading to a 6MT, then it wouldn't really matter what year the transmission & differential and driveshafts came out of?
 
#10 ·
the thing is the r180 is upgraded and bigger and can with stand the abuse of the 6mt sti transmission.
the r160 is smaller and cant withstand the abuse from a 6mt.

they will all bolt up into the same spots no problems at all. subaru never changed the drivetrain bolts patterns. you can swap the ring and pinion gears from the r180 to the r160 but it would be easier to just do the swap from a r160 to a r180

also the hubs on your car have a diffrent spline pattern than the sti transmission does.

the sti has a 24 spline and the wrx has a 20 spline male axle (i might be wrong but i know they have diff splines) so you will need the axles but other then that. thats all you need.. just make sure your wrx is not a ealry 2004 because the early 2004 wrx has axle stubs coming out of the transmission.

if its a early 2004 wrx and you get a 2004-05 sti transmission then you can sti axle stubs and use your old axles with no issues.

now the reason for the automatic driveshaft is because the sti transmission is longer then the wrx and also bulkier. also the splines on the prop shaft are different.
 
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