Difficulty getting into 1st gear when hot (and when AC is on?) - Manual Trans

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sonick

Member
:
2003 Mazda Protege5
We just got our first spell of warm weather here, and I noticed when I am driving in traffic for prolonged periods of time with the A/C on it gets increasingly difficult to shift into 1st (and other gears get notchier) from a complete stand-still. Is there some sort of safety that prevents accidental downshift into first that may be acting up?

Some other things I've noticed:
  • Slots into gear just fine immediately after engine is turned off
  • After some highway driving it gets easier to shift into 1st again
  • The A/C may or may not be causing or increasing the problem (I haven't done a real comparison yet)
  • When slow down to a stop, it shifts into 1st easily when I am at a very low speed and almost to a stop

Things I've done to try and stop this:
  • Front engine mount (side engine mounts seem ok)
  • Manual tranny fluid
  • Lubed up shift linkages

I am ordering some aftermarket Corksport bushings next, but I don't think that will make much difference.

Any ideas?
 
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trouble selecting gears is a common issue with clutch wear...specifically with the release bearing/collar...as that wears down, the clutch never fully disengages properly...making gear selection (particularly gears with a very short ratio i.e. 1st) a little annoying...next in line will be the shifter locking in place until the engine is off...if its only 'tight' for gear selection, this is probably the issue...however, if it makes noise/grinding...it could also be internal to the gear box, such as a shift fork or synchro...Is there any noise specifically when you JUST press the clutch in? as in, clutch disengaged but you're not touching the gear lever?...if you hear any noise in that case, its a strong bet on clutch problems, not gear box...

it works fine when the engine is off because the flywheel isn't turning...so it doesn't matter that the clutch disc is still grabbing the flywheel very slightly when the clutch pedal is pushed in...and its not quite as bad with the AC off, as the idle speed is slightly lower...making the problem a little less pronounced...the clutch disc is only partially engaged with the pedal in, so when engine rpm is significantly higher than idle...you probably don't notice it at all...its just a low engine speed threshold...

thats my best guess anyway...
 
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Thanks. There is no discernible noise at all, whether the clutch is pressed or not. I will pay attention if I hear anything with the clutch just pressed in.

Would the clutch/release bearing issue you describe be more pronounced with heat? As I only have the issue when it's hot and I am driving in stop & go traffic.
 
Been having the exact same problem. Stop and go traffic makes it incredibly hard to shift. It begins with 1st gear not wanting to engage, then 2nd becomes the same way. No grinding, just takes alot of muscle to get it in the gate. Highway cruising I am fine, but stop and go makes it happen every time.

For me the clutch pedal gets crunchy during stop and go. My pedal also makes a squeaking noise, which is coming from the engine bay. Haven't diagnosed exactly what it is yet.

I am planning on changing out the clutch line to stainless steel, replace the brake fluid and transmission fluid. Hopefully this fixes it, or at least temporarily mitigates it. I too feel it is the clutch, but I didn't realize it was so expensive on FWD cars. I will report back in a couple days when I do the work and go get myself stuck in some rush hour traffic.
 
I had this problem really badly before. I have been putting in some lucas oil stabilizer which really did help out my shifting. It does still happen to me especially when it gets really hot. But I've learned to get over it at this point and just start off in second gear if it doesnt go into first. No need to fix a clutch or trans if it's just random and only second gear, might as well wait till the trans is completely done with. Also if you havent changed your transmission oil you should def do that. I used redline MT-90. Good product.
 
I read in another thread saying a guy fixed it by adjusting his clutch pedal. I adjusted it last night and it seems to shift better; but the weather has cooled so I can't say for sure until I really do run it in traffic.

Other forums have suggested could be either the clutch master or slave cylinder going out as well.
 
the noise you hear when pressing the clutch pedal could be a different part, but still related to clutch disengagement...so i should've been a little more specific initially...something seems to be preventing your clutch from completely releasing...

that could be a release bearing (often called a throw out bearing), a clutch release cylinder, clutch master cylinder, clutch fluid line, a binding pedal, etc...or simply the pressure plate itself...but more often than not, a pressure plate will slip...the opposite of not letting go...

as far as the heat issue...not sure, exactly...it could be air in the line that is responding differently once the clutch is used more often...its easy to bleed the system, you don't even need to raise the car...
 
Ended up changing the clutch line, alone with new brake/clutch Fluid. The fluid came out a super dark green/black so I am assuming its been a while since it was changed last. The next day I took it on the 55 north from the 405 at 530 at night. Those of you that live in SoCal know that it is absolute stop and go at this time. The perfect proving ground! Drove it for about 30 minutes in these conditions, and it never stuck once. Just as seamless as when I had first started the car. My clutch pedal stays firm while in stop and go traffic, however the slight crunchy feel still shows up after a while. I think it is either the master or slave cylinder, but neither are leaking. I'll probably just end up replacing both in time.
 
sonick said:
I read in another thread saying a guy fixed it by adjusting his clutch pedal. I adjusted it last night and it seems to shift better; but the weather has cooled so I can't say for sure until I really do run it in traffic.

Other forums have suggested could be either the clutch master or slave cylinder going out as well.
Click to expand...

That was problaby me. I also replaced both the master and slave cylinder as well as adjusted the pedal. So far has been way better than before.
 
So after adjusting the clutch pedal and flushing with new brake fluid, the problem seems to have subsided. Spent all day Wednesday in stop-and-go city traffic, in the heat with the A/C on and had no problems. Fingers crossed.
 
Just an update, I recently discovered that my brake fluid reservoir cap was cracked and broken. It must have been leaking for awhile, but only this past weekend after a brake job did I really notice it.

After I replaced the cap I found my clutch feel was MUCH better and shifting much smoother. Just one more thing to check in case anybody has the same issue.
 
That's what I was going to say: fluid and/or line. getting worse with heat the way you describe is the key.

Just think, the exact same fluid is in your brake lines too. wonder how much better they'd feel after a flushing?

brake fluid (which is used in the clutch hydraulics) absorbs water VERY quickly. (it's designed that way chemically so you don't get pockets of water causing rust) Especially with a cracked cap, moisture gets in and as the fluid absorbs more and more water it works crappier and crappier. If it gets hot enough, the fluid boils. NEW DOT3 is rated at like 350f. With water in it, the boiling point drops FAST and it only takes a little. That's why you're supposed to flush the brake/clutch fluid every 2 years. I admit I don't do it either. Seems like bleeders that haven't been touched in 10 years open fine but if they've been opened once, they rust in place and break off the next time you open them no matter how you clean them.
 
So how would I go about adjusting my clutch pedal? Is it a simple bolt near the slave cylinder that I just loosen or something? I've tried the lithium grease in the cylinder it didn't do much. I've also swapped my clutch/brake fluid already, so was thinking I could tr adjusting the pedal a little like you said? Any simple instructions on how to do that?
 
kamesama980 said:
That's what I was going to say: fluid and/or line. getting worse with heat the way you describe is the key.

Just think, the exact same fluid is in your brake lines too. wonder how much better they'd feel after a flushing?

brake fluid (which is used in the clutch hydraulics) absorbs water VERY quickly. (it's designed that way chemically so you don't get pockets of water causing rust) Especially with a cracked cap, moisture gets in and as the fluid absorbs more and more water it works crappier and crappier. If it gets hot enough, the fluid boils. NEW DOT3 is rated at like 350f. With water in it, the boiling point drops FAST and it only takes a little. That's why you're supposed to flush the brake/clutch fluid every 2 years. I admit I don't do it either. Seems like bleeders that haven't been touched in 10 years open fine but if they've been opened once, they rust in place and break off the next time you open them no matter how you clean them.
Click to expand...

Well the fluid had been changed previously which helped but still shifted rough when hot. The reservoir lid replacement really made a significant difference.
 
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