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Transmission Grinding: Am I doing something wrong?

5410 Views 46 Replies 21 Participants Last post by  WandersX
I'm currently running a Koup SX 6 speed and here is my problem. Whenever I do a 3 - 6 shift my transmission grinds, in fact, if I do a 4 - 6 shift, my transmission grinds. So I'm wondering, am I not supposed to be shifting from third to sixth (say accelerating onto the highway then shifting into 6th to cruise)? I was always under the impression that this was okay. Does anybody else's transmission grind when doing this or should I get it checked by the dealer?
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I've been able to replicate the problem without fail every time since I noticed the problem. I am 6' tall and no winter mats, so its not that I'm not depressing the clutch all the way. I will give you exactly what I do when I face this grinding issue.

- Approach highway entrance, downshift into 2nd gear and take turn at roughly 15 - 20 mph.
- Begin acceleration in 2nd and shift to 3rd
- After I get to ~ 55 - 65 mph (roughly 4,000 - 4,200 rpm) I depress the clutch ALL THE WAY to the floor, I've even held it on the floor for a good 3 - 5 seconds to make sure that the clutch has fully disengaged.
- Pull shift knob out of 3rd (or 4th depending on where I was) and put it into 6th, at that time I hear grinding.

I'm 21 years old and have been driving manual on and off for the duration of my driving experience.
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I do not have any grinding issues going from 5th to 6th, however I can't find anything at all that I could be doing wrong?
Are you shifting quickly to 6th from 4th? Maybe not giving the tranny/engine enough time to sync up? Shifting between three gears needs to give time for the high engine rpm to match the low rpm of 6th gear at that moment.
That was one of my thoughts, however I gave the engine sufficient time to decline to 2,000 rpm before engaging 6th gear (2,000 rpm in 6th is roughly 60 mph based on my observations). Even after the engine hit 2,000 rpm I still had grinding issues.
I will try the double clutch method tonight and post back with my results
Alright, I've done some more tests and here are my results:

A 'double clutch' shift (shifting to neutral and releasing the clutch then shifting to sixth) does not cause the problem (I will try again later today on my way to work).

However that did sort of cause me to try another thing.

While accelerating to ~60mph in 3rd gear, with the clutch fully depressed, shifting into 6th causes grinding, once in 6th, I pushed the clutch down again, shifted out and shifted back in (releasing the clutch while in neutral), no grinding.

While driving at about 30 - 35mph in 3rd gear (usually I'd cruise in 4th but this was for experimental purposes) I fully depress the clutch and put the transmission into 6th, without re-engaging the clutch - no grinding.

My final test was to, while traveling at ~30 mph, push down the clutch, and bring the engine's rpm to 4,000 - then immediately put the car in 6th gear (without re-engaging the clutch), still no grinding.

Therefore, to me, it seems that the transmission only grinds when shifting from 3rd (or 4th) straight to 6th while under load.

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Alright, so here's an update: the car was brought to the dealership, one of the tech's wanted to see it after I described the problem since there's a known issue with 6th gear completely failing (lol).

However that wasn't the problem with my car, they don't know if it's a defect or 'just how the transmission is designed' so they're calling the engineers in Cali. to figure out what the deal is.

They also replaced a part (which I don't know just looking at the invoice) under warranty:

STEER/SUSP RECALL (Part number 54619-1M000QQK) PAD... Don't know what that is.

Anyway, we'll see what happens
Got an answer today, here's the TechLine transcript:

*** NOTES 12/14/2010 05:47 AM clarify Action Type: Manager review
*** Performed by contact:
*** This is a Request for Assistance ***

Problem Description :
Customer states that they cant shift from third gear (with rpm's high) into sixth gear. Fourth and fifth gear go in ok. Third to sixth shift grinds.

Diagnostics Performed :
Test drove and verified concern. Is this normal?

*** PHONE LOG 12/14/2010 06:09 AM Pacific Daylight Time RHicks Action Type:Incoming call
Advice 1:
I believe this is normal... I'm driving one now and it does the same...
it is recommenced to shift all the way through gear pattern normally
- this reduces wear on blocking rings/springs and syncros
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