dude that sucks, I hope you get that fixed!

 

I don't know why but it seems the 05's commonly have a 4th gear syncro issue when being driven...our shop STi developed a notchy 4th gear shift too...it was/is an 05.

 

I've fixed the 4th gear grind on an STi (and 1st gear grind on a WRX) by using one quart of Penzoil synchomesh in with 75w90 Valvoline NON-syn plain ol' tranny fluid (don't overfill it).

I reccomend getting the car back ASAP.
Escalate to SOA...and wait for resolution.
If that doesn't help, do my trick above.

 

Let the dealership look at it homemadewrx is right about the specialty tools. At my dealership we have a huge torque wrench. Also there is alot more with this tranny it even has its own oil pump. We are taking one appart right now at my dealership.So just to be safe let the dealership do it. Also if they decide to warranty or not when the tranny is fixed it does go back to the original warranty. Im not sure how it is if a different shop does the work.

 

better yet...
1 qt of redline heavy or light shock proof,
1 qt pensoil syncromesh
2 qt of regular 75w-90

see if it helps for now...kind of a bandaid really

 

Also Subaru makes a synchomesh for the sti and wrx if you want to try getting rid of the grind that way. Before havin it taken appart.

 

Sometimes this works but it most likely is a syncro problem.I would let them tear it down and see what subaru has to say they are very reasonable the dealership needs to have auth. because if subaru doesn't cover the repair the dealership doesn't get paid to diagnose it.Ask yourself would you take apart a six speed transmission for free?

 

They will deny u then did it to me 3700 later i got my car back from mastro i tried to go through SOA but the didnt help anything

 

this sucks subaru should really back up the 60k mile powertrain warranty!
i have a 04 sti that ive had for 6 months and my 4th gear started doing the same thing and now i have no 4th gear and to top it off my 5th gear is started to gring as well. dude we should go to the dealership and complain.

 

^ learn how to drive your Subaru and you wouldn't have problems.