Occasional issue shifting into first

[dag01]

I'm new to driving a stick, been driving for about a month. 2003 subaru impreza wrx. Occasionally when I'm driving, I have trouble moving the shifter into first gear. It is.. rough? And makes a grinding, farty noise. The first time I did it, my girlfriend(who has driven a stick for years) said that I didn't have the clutch all the way down (I did). I was confused, but went on my day. A few days later, it happened again. This time I was SURE my clutch was all the way down, but she wasn't there. The car was rolling a bit and my first gear usually locks if you're rolling, so I thought maybe it was that. A few days later the car was completely stopped and it did it again. I don't know what it is. Anyone have any ideas?

[Rope-Pusher]

Make sure the clutch pedal is.......



....pushed all the way.

How long does your clutch take to spin down from idle after the pedal is pushed to the downstop?

Assuming you don't have a synchronized REVERSE gear, hold the shift lever poised in Neutral, with the engine idling, push down the clutch pedal and count "1,2,3,Pizza, Pizza, Pizza!" and then shove the shift lever into REVERSE. Does it make a terrible sound? If so, the clutch was still spinning. If not, try it again, counting "1,2,3,Pizza Pizza!" and shove it into REVERSE. Still no gnashing of teeth? Next time count "1,2,Pizza, Pizza!"

Eventually, you'll come to find out if your spin-down time is 3, 2.5, 2, 1.5 or even 1 second. Again, if it is infinite, or longer than 2.5 seconds, you need to get the clutch to disengage more fully before you shift. There may be air in the clutch release hydraulics, or there may be scaly rust on the transmission input shaft. Does the clutch begin to engage with the pedal less than an inch off the floor - think air in the hydraulics. If the engagement point is 1" or more off the floor, the problem may be the rusty shaft. You may also help things out by giving the clutch a little extra time to spin down before you try shifting into first or reverse. Think "Little Caesar's" after you push down the clutch pedal before you shift.

[dag01]

Make sure the clutch pedal is.......



....pushed all the way.

How long does your clutch take to spin down from idle after the pedal is pushed to the downstop?

Assuming you don't have a synchronized REVERSE gear, hold the shift lever poised in Neutral, with the engine idling, push down the clutch pedal and count "1,2,3,Pizza, Pizza, Pizza!" and then shove the shift lever into REVERSE. Does it make a terrible sound? If so, the clutch was still spinning. If not, try it again, counting "1,2,3,Pizza Pizza!" and shove it into REVERSE. Still no gnashing of teeth? Next time count "1,2,Pizza, Pizza!"

Eventually, you'll come to find out if your spin-down time is 3, 2.5, 2, 1.5 or even 1 second. Again, if it is infinite, or longer than 2.5 seconds, you need to get the clutch to disengage more fully before you shift. There may be air in the clutch release hydraulics, or there may be scaly rust on the transmission input shaft. Does the clutch begin to engage with the pedal less than an inch off the floor - think air in the hydraulics. If the engagement point is 1" or more off the floor, the problem may be the rusty shaft. You may also help things out by giving the clutch a little extra time to spin down before you try shifting into first or reverse. Think "Little Caesar's" after you push down the clutch pedal before you shift.

I didn't know that this mattered, but it makes sense. I'll give it a shot tonight and let you know. Thanks!

[theholycow]

The workaround for smooth engagement if your clutch doesn't completely stop spinning is to shift into another gear before 1st or reverse. I shift into 2nd, or at least touch 2nd's synchro, often before I shift into 1st. I shift into 5th almost every time before shifting into reverse.

RP, what do you think of this: When my car is cold, my clutch spins down to a stop well enough. When warmed up, it does not spin down to a complete stop at all, so I am required to stop it with 5th before shifting into reverse. Marginally insufficient release clearance, where the thermal expansion of the assembly closes that gap, maybe?

Edit: Another idea...input shaft thermal expansion. My workmanship grinding the splines into it was craptastic so they could be marginal. There's also the excess length issue, it may be almost bottoming out in the crankshaft pilot hole. Or, it may be expanding and binding in the pilot bushing.

[kayubassist]

wow.
i learned something new today.

[Rope-Pusher]

Cowabunga,
I'm wandering if your hydraulic line is plastic and is getting exhausted and softened from the heat.
The pressures are high enough in the system for it to be noticeable when the the loins are soft.

[theholycow]

It is definitely plastic. You may remember the first time I got it working and it melted against the exhaust manifold. After that I made sure to route it far from the manifold, except maybe where it meets the slave cylinder it's probably closer than I'd want.

Any suggestions for easy cheap kludges? Some kind of insulation that might work? Maybe wrap it in a longitudinally sliced piece of rubber hose and/or wire loom? It's not severe enough to be worth replacing the line.

I think it happens before underhood air temperatures are high enough, though.

[Rope-Pusher]

get some fiberglass pipe wrap and after you wrap the line, secure it with twists of bailing wire or garbage bag twist-ties - if they get hot enough the paper chars and burns off and you are left with the wire.

If you think the problem is radiant heat, wrap the fiberglass pipe wrap with heavy-duty aluminum foil. I have also used aluminum tape to give a reflective surface over the fiberglass.