1st gear hard to engage unless stopped, Subaru 2004 Impreza Outback Sport

Question

Since I've bought my 2004 Impreza Outback Sport, I've had a problem with shifting into 1st gear.

• First gear is generally difficult to engage while moving.
• You can just force it, but it's really quite hard.
• If I'm stopped, or going really really slow, there's no shifting resistance at all.
• No other gears have this problem.
• The problem is not 100% consistent -- I'd say it happens 80%-90% of the time.
• Anecdotally, it seems to be less of a problem after I've been on the road a little while.

Based on this post, the problem might be about a gear synchronizer.

My questions are:

1. What might be wrong here?
2. How can I further test what is the problem?
3. Can I fix or replace this part myself? How much harder will it be than what I've done before? (See my experience below)
4. Is it worth fixing the specific broken/worn part, or should I replace an entire assembly of some kind? (e.g., clutch)
5. Can you point me towards informational resources that could help me to fix this DIY?

My experience and tools: I have successfully replaced a rear strut assembly and two front axles without too much trouble. I have a floor jack and 2 stands at my disposal, plus a full ratchet set and torque wrench (20 to 150 ft/lbs).

Answer 1

I'm assuming no one here answering has driven a Subaru manual transmission before or long enough. I'm fairly certain there is nothing wrong with your synchros or transmission. Subaru's are generally very hard to shift into first while in motion. I daily-drive a 2011 WRX and and the first gear has always been like that, even when it was brand new. I have driven various manual Impreza's over the years and they are all like that. This is just another Subaru quirk. If you need to downshift into first for some reason, heel toeing wouldn't really help either since you can't even move the shifter into first gear. You should instead try double clutching to downshift. This usually always does the trick. Changing out your manual transmission fluid also helps a bit too. If I recall correctly, Subaru recommends changing it every 30,000 miles. There really isn't any reason to downshift into first gear unless you have to climb a really steep hill and second gear isn't cutting it. Usually when I'm crawling really slowly in second I can shift into first gear without a problem. It's only at speed where it becomes difficult to downshift into first and honestly I don't think I have ever needed to do this.

Answer 2

This possibly isn't worth fixing - I certainly wouldn't fix it.

In general you shouldn't use 1st gear except for starting off from stationary. The synchro for 1st gear is different to the others for this very reason. What you probably have done is worn the synchroniser out through not matching revs accurately. If you absolutely must change into 1st while moving, then match revs (by heel-and-toeing) for example.