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6th Gear Grind

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Old Sep 3, 2006 | 10:54 PM
  #1  
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Default 6th Gear Grind

I just traded my A4 for another C5.

Its a 6 speed and has 90k miles.

At very high racing rpms, 4th gear will sometime grind.

BUT,
At any rpm's even 1500 rpms shifting into 6th will ALWAYS grind.

Im assuming that the previous owner NEVER changed the diff and tranny fluid so im going to do that tomorrow and im hoping that it will fix it.

Id be surprised if the 6th gear synchro was out. How often do you shift into 6th gear and even if you do its usually under 4000 rpm!

I also have a short shifter that im currently hating (not sure what brand it is but it is ridiculously notchy and sometimes its hard to find the 5th and 6th gates)

Could it be misaligned and also causing this grind? aside from that the tranny is great shape - 1st to 2nd is flawless, 3rd is great, 4th is a little etchy at 5-6k rpms 5th is great and 6th just loves to grind every single time..
Tomorrow im going to change the fluid to redline or royal purple (whichever is cheaper or available) and hopefully that will help?


anyone have any input!?
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Old Sep 3, 2006 | 10:56 PM
  #2  
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Originally Posted by RickC5
I just traded my A4 for another C5.

Its a 6 speed and has 90k miles.

At very high racing rpms, 4th gear will sometime grind.

BUT,
At any rpm's even 1500 rpms shifting into 6th will ALWAYS grind.

Im assuming that the previous owner NEVER changed the diff and tranny fluid so im going to do that tomorrow and im hoping that it will fix it.

Id be surprised if the 6th gear synchro was out. How often do you shift into 6th gear and even if you do its usually under 4000 rpm!

I also have a short shifter that im currently hating (not sure what brand it is but it is ridiculously notchy and sometimes its hard to find the 5th and 6th gates)

Could it be misaligned and also causing this grind? aside from that the tranny is great shape - 1st to 2nd is flawless, 3rd is great, 4th is a little etchy at 5-6k rpms 5th is great and 6th just loves to grind every single time..


any help!?
Ive had my 6th gear grind, while going in at a low rpm. If I double clutch, and rev match, it never grinds.
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Old Sep 3, 2006 | 11:01 PM
  #3  
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From: Waldorf MD
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Check your clutch fluid, add if low. It fixed my 6th gear grind!
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Old Sep 4, 2006 | 12:38 PM
  #4  
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Fluid change cured my grind issues.JER
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Old Sep 4, 2006 | 08:36 PM
  #5  
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From: East Hampton CT
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I was getting into a hard acceleration in 1'st and 2'd and then at the top of 2nd I was dumping into 6th for highway cruising. However, the synchros are NOT designed to be slapping your car into 6th gear at ~6000 rpm (you'd be doing 180+mph!) so I have started letting the rpms drop before putting it into 6th and it stopped the grinding. I also sometimes quickly hit 4th or 5th before 6th to get everything up to speed in the tranny.
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Old Sep 5, 2006 | 01:16 AM
  #6  
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RickC5
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From: Miami/Ft. Lauderdale FL
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oh well,
On normal driving, the car doesnt grind.

I guess i can handle a little bit of a grind when im racing someone.

Im gonna try to put synchromesh into the mn6.. (the Camaro guys swear by it) and see if it stops all the grinding.

In my previous car, i had a really bad 3rd gear that would grind shifting into it at just 3k rpms.. Put in GM Synchromesh and 3rd gear was then able to handle 7k rpm shifts!

Hopefully it will do the same for the C5.

If not, I can grab another tranny for down the road for ~1000 bucks...
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Old Sep 5, 2006 | 07:01 AM
  #7  
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From: Central Florida
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Suggest you be very meticulous about cleaning up your clutch hydraulic fluid. At 90K miles it's certainly going to be badly degraded and a source of improper clutch disengagement issues.

If you do your own wrenching then a full bleed of the clutch hydraulics is best. If that's beyond your comfort zone, then here are some threads to review that will enable you to do repeated swaps of the fluid in the clutch hydraulic master cylinder reservoir. Given 6-10 swaps, it should get clean enough at a cost of less than $10.

With that in mind, here are three clutch fluid issue threads to review:

Clutch Pedal Woes--Fluid Impact

C6Z06 Clutch Hydraulic Fluid--the Chevy Spec

Clutch Pedal Woes--Fluid Changing Kit

http://ls1gto.com/forums/showpost.ph...5&postcount=18

Ranger
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