4th gear synchro
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Joined: Sep 2006
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From: kevil kentucky
4th gear synchro
I'm sure this thread has come up over and over, but i cant find exactly what im looking for. I grind from 3rd to 4th in my 98 6 spd. I imagine ive worn out the synchro but im no expert when it comes to this. anything else i should look into? And what should i expect to spend to have it repaired?
Tech Contributor
Joined: Aug 2008
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From: Oak Hill Virginia
I'm sure this thread has come up over and over, but i cant find exactly what im looking for. I grind from 3rd to 4th in my 98 6 spd. I imagine ive worn out the synchro but im no expert when it comes to this. anything else i should look into? And what should i expect to spend to have it repaired?
The cost depends on how much of your own work you can do. Dropping the drivetrain will usually cost 5 - 7 hours of labor, so... $500 - $800. Disassembling the transmission and putting it back together with new components will usually cost between $400 - $700 for the labor plus the cost of parts.
I would very highly recommend either RKT56 or RPM Transmissions...
Tech Contributor
Joined: Jan 2004
Posts: 20,030
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From: Wylie TX --> Less is More, except under the hood !
Too bad your not local to Dallas. My tuner rebuilds 6 speeds in his shop with ALL RPM good stuff. He did mine for around $1600 removed/rebuild/installed. Feels AMAZING NOW !!!
Mine was also suffering the 3-4 grinding issue on occasion.
I would recommend RPM rebuild it for you.
Toque
Mine was also suffering the 3-4 grinding issue on occasion.
I would recommend RPM rebuild it for you.
Toque
Tech Contributor
Joined: Sep 2005
Posts: 1,731
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From: New Market AL
My '99 MN6 is currently grinding 4th - well only if I forget and try to use 4th. I have priced out the parts to rebuild a C5 T56, and just the parts to rebuild plus upgrade to "Level 2" are close to $900. I picked up a M12 rebuildable core so I can build it at my own pace, and then swap out my MN6 with minimal downtime.
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Joined: Jan 2011
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From: Peoria Arizona
I am also grinding into 4th if i am not careful. What I have found is that if i press the clutch coming out of 3rd, let it out and then press it again while going into 4th, it never grinds. I am going to try and flush/bleed the system. heard that helps...dont know if maybe that might help for a temporary fix. one can dream i guess 
Safety Car
Joined: Jun 2009
Posts: 3,888
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From: Frederick, Maryland
My '99 MN6 is currently grinding 4th - well only if I forget and try to use 4th. I have priced out the parts to rebuild a C5 T56, and just the parts to rebuild plus upgrade to "Level 2" are close to $900. I picked up a M12 rebuildable core so I can build it at my own pace, and then swap out my MN6 with minimal downtime.
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
I am also grinding into 4th if i am not careful. What I have found is that if i press the clutch coming out of 3rd, let it out and then press it again while going into 4th, it never grinds. I am going to try and flush/bleed the system. heard that helps...dont know if maybe that might help for a temporary fix. one can dream i guess
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Tech Contributor
Joined: Sep 2005
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From: New Market AL
I did a price comparison with 3 suppliers (including TheGearBox). What I am buying is a basic rebuild kit (including carbon rings, seals, lock rings) plus upgraded bronze fork pads, solid keys for 3-4 synchro, steel 3-4 shift fork, and a complete 5-6 synchro assembly. A basic rebuild will cost ~$500 in parts. With these upgrades and me having to replace the 5-6 synchro assembly ($115) it will run me a little over $800.
Safety Car
Joined: Jun 2009
Posts: 3,888
Likes: 2
From: Frederick, Maryland
I did a price comparison with 3 suppliers (including TheGearBox). What I am buying is a basic rebuild kit (including carbon rings, seals, lock rings) plus upgraded bronze fork pads, solid keys for 3-4 synchro, steel 3-4 shift fork, and a complete 5-6 synchro assembly. A basic rebuild will cost ~$500 in parts. With these upgrades and me having to replace the 5-6 synchro assembly ($115) it will run me a little over $800.
Racer
Joined: Aug 2011
Posts: 279
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From: MN
Yep, my fourth grinds when it is cold if I drive how I normally do. To prevent the grind I just hold the clutch in a tid' bit longer until the revs come down to perfectly match. I have not had it grind once yet doing this.
