I’m not sure if this is a common issue or not. I have a 5-speed manual 2002 Subaru Impreza TS Wagon, and although this is my first Subaru, my previous cars haven’t had this issue.
When I downshift into first gear, it grinds before slipping into place. There is talk about a transmission fluid cocktail that will fix this, but I’m not convinced this is a common problem, but it may be. This happens as I’m coming to a stop, but also when I am stopped. Not 100% of the time, but around 60% of the time. Does anyone else have this problem that they’ve rectified?
Thanks!
I have a similar generation Impreza although 04 WRX model. I must be going somewhere less than 5mph before downshifting to 1st gear. It was quite annoying when I bought the car but now do not think about it after driving it 6years/75k miles. My wifes 2005 Legacy GT does not do this at all.
I just consider a simple quirk of a WRX(at least 02-05 generation).
Hi there, thanks for the reply. It is annoying, indeed, but I am getting used to it.
I’m having a similar problem with my 2003 Outback Sport - not just 1st, but also Reverse… From the show - common causes are: Low level of transmission fluid (unfortunately the manual doesn’t have a dispstick so I think I’m stuck jacking it up), improper viscosity, or a toasted transmission… I’m hoping for (1) or (2) - will let you know 
An out of adjustment or worn clutch can be responsible for this up to a point.
After that, the problem will lie in not just the synchronizers but the entire synchronizer assembly.
Any fluid or fluid cocktail is not the cure although I suppose it may be possible to mask the problem a bit.
I’m not a fan of the way Subaru synchronizers are made anyway. Basically a synchronizer ring is supposed to be a brake shoe of sorts and stop the gear from spinning when the transmission is shifted. This will then allow a smoother shift.
You can take a brand new Subaru gear and brand new synchro ring and even when bone dry one can turn the ring on the gear cone by hand even when applying a lot of force. What SHOULD happen is that the ring ought to lock down tight on the gear cone.
Once the parts become used then imagine what will occur.
Inspect the clutch and clutch adjustment and hope that is the biggest cause of this problem.