Grind going into 3rd gear

[godbiggy]

Hi guys, I had this grind occur during my shift from 4th > neutral > 3rd




I was cruising around 4th gear at 40km/h and decided to put in neutral as I was coming to the stop light... and had the clutch in for a good 5-10 seconds, then all of a sudden the light turned green


so then I decided 3rd gear would be best at 30km/h... as I was slowly pushing it into 3rd, I heard this faint grind so I backed off and put it in firmly with no issue.


My question is... is this normal? and would the issue be I was holding the clutch in to long? so the shaft or gear (whichever is disengaged) slow down and not mesh?


this was all done during clutch fully depressed on a 2015 Subaru BRZ 45k KM.


thanks in advance

[humfrz]

Hi @godbiggy and welcome to Ye Ol Forum -

Yep, I reckon you confused your transmission gears and synchronizers.

I would suggest that when you shift from 4th down to 3rd, just push in on the clutch, blip the throttle and move the shift lever - in that order - all within a 1-3 second time frame.

If you would like a detailed explanation I will ring up ol @Ultramaroon for you and, if he not in a cranky mood, he will explain it to you. -


humfrz

[soundman98]

to be clear, are you not rev-matching the downshifts? that's the main reason to have a manual!

i grind occasionally, today, i accidentally started from a stop in 3rd. it happens. just let the motor sing to redline to apologize

[godbiggy]

Originally Posted by humfrz

Hi @godbiggy and welcome to Ye Ol Forum -

Yep, I reckon you confused your transmission gears and synchronizers.

I would suggest that when you shift from 4th down to 3rd, just push in on the clutch, blip the throttle and move the shift lever - in that order - all within a 1-3 second time frame.



humfrz

Hey Humfrz I see that you said blip the throttle and move into the selected gear, meaning rpms have a role in allowing the shifter to enter the gear?

What I'm really just confused on is why did it grind when I had my clutch fully depressed? I never had this happen

Thanks for replying tho

[godbiggy]

Originally Posted by soundman98

to be clear, are you not rev-matching the downshifts? that's the main reason to have a manual!

i grind occasionally, today, i accidentally started from a stop in 3rd. it happens. just let the motor sing to redline to apologize

I usually blip and downshift into 3rd gear, which goes in like butter but this time I cruised in neutral holding clutch in for 5-10 seconds

And when I decided to push it into 3rd it just had a faint grind, this all occurred during the clutch being fully depressed which is confusing

[soundman98]

i see. the simple answer is the revs fell too far.

the longer answer is the input and output shaft speeds became drastically different, forcing the syncro's to work harder, which created friction and more force on the gearstick lever.

it happens to all of us, but it's generally something you don't want to make a habit of

[humfrz]

Originally Posted by godbiggy

Hey Humfrz I see that you said blip the throttle and move into the selected gear, meaning rpms have a role in allowing the shifter to enter the gear?

What I'm really just confused on is why did it grind when I had my clutch fully depressed? I never had this happen

Thanks for replying tho

That's correct about the rpms.

I see ol @soundman98 explained "how it works" -

https://auto.howstuffworks.com/manua...chronizers.htm


humfrz

[Howaitoguru]

Sometimes mine grinds going into first, and acts like it wants to pop out. I’ve put about 5000 miles on my car since I got it though and haven’t really had any real issues. The gearbox is funky sometimes, but like everyone else said when down shifting you always want to give it some throttle. Also down shifting to 2nd gear make sure you’re not over 50mph or you’ll probably be in a bad mood for the rest of the day.


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[RToyo86]

I notice sometimes 2-3 shift sounds a little crunchy like a grind.

I think it mostly has to do with a lazy shift, and not being 100% on the floor with the clutch.

[churchx]

If grind doesn't repeat, non fully disengaged clutch is one of most probable reasons. Slight clutch drag - synchros not working well to even out speeds, and here you go, gears grind.

[soundman98]

Originally Posted by Howaitoguru

Sometimes mine grinds going into first, and acts like it wants to pop out. I’ve put about 5000 miles on my car since I got it though and haven’t really had any real issues. The gearbox is funky sometimes, but like everyone else said when down shifting you always want to give it some throttle. Also down shifting to 2nd gear make sure you’re not over 50mph or you’ll probably be in a bad mood for the rest of the day.


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not exactly.

Originally Posted by FR-Sky

I found this on other website:
"Road & Track, July 2012 issue, pg. 89.

At 7400 rpm the speeds in each gear are respectively:

1: 35 mph (too much commotion in town)

2: 58 mph

3: 83 mph (you could be in trouble)

4: 105 (you're probably going to jail)

5: 127 (do you have a lawyer?)

6: 135 (estimated at 6000 rpm, so I assume it's drag limited)

RPM at 60 mph in top gear: 2700

Hope this helps."

I was doing a pull on the freeway, and I didn't notice that I went over the redline on 2nd gear and it is showing 61mph before I shift to 3rd.
Does any one experience this?

because i routinely drop from 4th to 2nd into and out of cloverleafs, with a general entry speed around 40-50. i know i'm doing 60 at fuel cut..

[Howaitoguru]

Originally Posted by soundman98

not exactly.







because i routinely drop from 4th to 2nd into and out of cloverleafs, with a general entry speed around 40-50. i know i'm doing 60 at fuel cut..

My shit red lines if I’m not at 50mph when I shift to second.


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[Howaitoguru]

Originally Posted by Howaitoguru

My shit red lines if I’m not at 50mph when I shift to second.


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Down shift*


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[soundman98]

ah, didn't they drop the final drive ratio in '16? i want to say they did, which would then make sense..