Grinding 4th and 5th gear

SpeedAddictSTI · 05-12-2008, 06:41 AM

Hey guys,

I'm curious to why this is, I mean I really don't beat on my car to hav ethis happening. It seems to be happening once the car is warmed up too. I changed the trans oil with redline syn oil and was wondering if that was it, or if the clutch might be slowly going. Does anyone else have this problem on a 2004 sti? If so, what did you do to fix it. I have roughly 84k miles now.

ChristianCGM · 05-12-2008, 07:36 AM

MY04-05 STi's have brass synchros, in MY06 and newer Subaru solved this problem by carbon plating the synchros to make them stronger. If the synchros are worn significantly then the only resolution is replace them, but since you are beyond warranty it will be expensive. I had a 5th gear grind at 29k miles and have been using a Royal Purple 75w90 Gear Max and SynchroMax combination switching it every 20k. I am now at 78k miles and have never had any brass powder or any kind of residue on the magnetic drain plug or on the tranny under pan when doing a fluids change.

Mykl · 05-12-2008, 11:27 AM

First step... get some Subaru Extra-S fluid in it and see if that fixes it.

If it doesn't, you may have to bite the bullet and have somebody go in after the syncro. Hopefully the MY06 part number replaces the MY04/05 part numbers and you get the updated part.

I have 34k miles on my car with a handful of track days, which means a lot of shifting between 4th and 5th, and my syncros are still happy at the moment.

1loudsti · 05-12-2008, 12:08 PM

i have it too....05 mine will do it into 5th any time i shift in the upper rev range doesnt matter if its a quick shift or a normal shift, still goes in you just hear/feel the zzzrrrckk (lol) noise as it does

any particular brand of syncromax? im running straight amsoil SVG and its not as bad maybe that will help some too

Crozetian · 05-12-2008, 12:17 PM

I was getting 3rd to 4th grind on a new 08 STI. Dealer just replaced gear oil with Extra-S and, knock on wood, it seems to have gotten much better (not sure yet if it's completely cured). You will be interested in these two threads on NASIOC:

SOA "G-O Extra-S" Gear Oil Update - NASIOC

Factory Subaru Gear Oil - NASIOC

Mykl · 05-12-2008, 12:23 PM

I keep saying it, and I'll say it one last time in this thread because I don't want to come across as preachy... but the car's OEM fluid, Extra-S, is the very best you can do for this gearbox for all but the most extreme situations.

rs_wrx_sti · 05-12-2008, 12:59 PM

For trannys and diffs it's best to stick with the OE Subaru fluids.

KiTsuNe · 05-12-2008, 01:08 PM

syncros! i just had them all replaced in MY04 for 1400ish and that includes labor and parts.

Mykl · 05-12-2008, 01:18 PM

Quote:

Originally Posted by KiTsuNe

syncros! i just had them all replaced in MY04 for 1400ish and that includes labor and parts.

Did that include install and removal of the gearbox? Where did you get it done?

Did they use updated '06+ syncros?

KiTsuNe · 05-12-2008, 01:47 PM

yes i did! and yes they did hehe, got it done at a tranny shop my friend's dad recommended

JuanP · 05-12-2008, 02:23 PM

i have the same problem with 4th i've got a 05 with 54k on it. does the powertrain warranty cover this syncros problem?

Mykl · 05-12-2008, 02:32 PM

Quote:

Originally Posted by KiTsuNe

yes i did! and yes they did hehe, got it done at a tranny shop my friend's dad recommended

Nice, that's a great price you got. I'm afraid that when I need to get mine serviced I'm going to have to crate it up and ship it out.

ytsohptwhere · 05-12-2008, 02:41 PM

Quote:

Originally Posted by ChristianCGM

I had a 5th gear grind at 29k miles and have been using a Royal Purple 75w90 Gear Max and SynchroMax combination switching it every 20k.

Can you explain what you mean by switching it every 20k miles? Are you using both oils at the same time and mixing them or are you using Gear Max then at the next fluids change switching to SynchroMax? Thanks!

I have same problem on an 04 STi 5th gear. Fast or Normal shift gives the grind.

polyol · 05-12-2008, 02:42 PM

My 5th gear syncro's went out at 50,000...had it fixed under warrentee...not sure how much the dealership charges but I bet it isnt cheap.

KiTsuNe · 05-12-2008, 02:57 PM

my 4th gear went out first, it got to the point where it would kinda go in, but the second you gas it the thing flies out and grinds. I had the tranny apart and just replaced ALL for safe measure and so i dont have to deal with the other ones going out.

05-12-2008, 06:41 AM	#1
SpeedAddictSTI Lurker Car: Java Black 04 STI Fav Mod: K&N Typhoon Air system Location: Connecticut Posts: 7 Join Date: Jun 2007 Trader Rating: (0)	Grinding 4th and 5th gear Hey guys, I'm curious to why this is, I mean I really don't beat on my car to hav ethis happening. It seems to be happening once the car is warmed up too. I changed the trans oil with redline syn oil and was wondering if that was it, or if the clutch might be slowly going. Does anyone else have this problem on a 2004 sti? If so, what did you do to fix it. I have roughly 84k miles now. This ad is not endorsed by this member. Please register or login to hide this ad.

05-12-2008, 07:36 AM	#2
ChristianCGM Grassroots STI Racer Car: 05 STi CGM Fav Mod: whiskey tango Posts: 550 Join Date: Oct 2005 Trader Rating: (2)	Re: Grinding 4th and 5th gear MY04-05 STi's have brass synchros, in MY06 and newer Subaru solved this problem by carbon plating the synchros to make them stronger. If the synchros are worn significantly then the only resolution is replace them, but since you are beyond warranty it will be expensive. I had a 5th gear grind at 29k miles and have been using a Royal Purple 75w90 Gear Max and SynchroMax combination switching it every 20k. I am now at 78k miles and have never had any brass powder or any kind of residue on the magnetic drain plug or on the tranny under pan when doing a fluids change.

05-12-2008, 11:27 AM	#3
Mykl S204 Racer Car: '04.5 STi Fav Mod: ZZYZX Location: Montgomery, Al Posts: 2,749 Join Date: Apr 2006 Trader Rating: (0)	Re: Grinding 4th and 5th gear First step... get some Subaru Extra-S fluid in it and see if that fixes it. If it doesn't, you may have to bite the bullet and have somebody go in after the syncro. Hopefully the MY06 part number replaces the MY04/05 part numbers and you get the updated part. I have 34k miles on my car with a handful of track days, which means a lot of shifting between 4th and 5th, and my syncros are still happy at the moment.

05-12-2008, 12:08 PM	#4
1loudsti Professional STI Driver Car: CGM 05 Fav Mod: cobb ap v2 w/ LC Location: racine,wi Posts: 465 Join Date: Mar 2008 Trader Rating: (1)	Re: Grinding 4th and 5th gear i have it too....05 mine will do it into 5th any time i shift in the upper rev range doesnt matter if its a quick shift or a normal shift, still goes in you just hear/feel the zzzrrrckk (lol) noise as it does any particular brand of syncromax? im running straight amsoil SVG and its not as bad maybe that will help some too

05-12-2008, 12:17 PM	#5
Crozetian Amateur STI Driver Car: 08 Subaru STI Fav Mod: Coming Soon Location: Charlottesville, Virginia Posts: 11 Join Date: Dec 2007 Trader Rating: (0)	Re: Grinding 4th and 5th gear I was getting 3rd to 4th grind on a new 08 STI. Dealer just replaced gear oil with Extra-S and, knock on wood, it seems to have gotten much better (not sure yet if it's completely cured). You will be interested in these two threads on NASIOC: SOA "G-O Extra-S" Gear Oil Update - NASIOC Factory Subaru Gear Oil - NASIOC

05-12-2008, 12:23 PM	#6
Mykl S204 Racer Car: '04.5 STi Fav Mod: ZZYZX Location: Montgomery, Al Posts: 2,749 Join Date: Apr 2006 Trader Rating: (0)	Re: Grinding 4th and 5th gear I keep saying it, and I'll say it one last time in this thread because I don't want to come across as preachy... but the car's OEM fluid, Extra-S, is the very best you can do for this gearbox for all but the most extreme situations.

05-12-2008, 12:59 PM	#7
rs_wrx_sti Junior STI Driver Car: 07 GDB-G WRB STi Fav Mod: shift knob Location: SoCal Posts: 139 Join Date: Apr 2007 Trader Rating: (0)	Re: Grinding 4th and 5th gear For trannys and diffs it's best to stick with the OE Subaru fluids.

05-12-2008, 01:08 PM	#8
KiTsuNe Spec C Club Car: The Vroom-mobile Fav Mod: JDM Gears Location: San Jose, California Posts: 2,287 Join Date: Jun 2005 Trader Rating: (1)	Re: Grinding 4th and 5th gear syncros! i just had them all replaced in MY04 for 1400ish and that includes labor and parts.

05-12-2008, 01:47 PM	#10
KiTsuNe Spec C Club Car: The Vroom-mobile Fav Mod: JDM Gears Location: San Jose, California Posts: 2,287 Join Date: Jun 2005 Trader Rating: (1)	Re: Grinding 4th and 5th gear yes i did! and yes they did hehe, got it done at a tranny shop my friend's dad recommended

05-12-2008, 02:23 PM	#11
JuanP Amateur STI Driver Car: Black 05 WRX STi Fav Mod: Coming Soon QTP downpipe? Location: Reno, NV Posts: 8 Join Date: Oct 2007 Trader Rating: (0)	Re: Grinding 4th and 5th gear i have the same problem with 4th i've got a 05 with 54k on it. does the powertrain warranty cover this syncros problem?

05-12-2008, 02:42 PM	#14
polyol Spec C Club Car: 04 STi Fav Mod: Motor Mounts Location: Eugene Posts: 2,186 Join Date: Oct 2004 Trader Rating: (0)	Re: Grinding 4th and 5th gear My 5th gear syncro's went out at 50,000...had it fixed under warrentee...not sure how much the dealership charges but I bet it isnt cheap.

05-12-2008, 02:57 PM	#15
KiTsuNe Spec C Club Car: The Vroom-mobile Fav Mod: JDM Gears Location: San Jose, California Posts: 2,287 Join Date: Jun 2005 Trader Rating: (1)	Re: Grinding 4th and 5th gear my 4th gear went out first, it got to the point where it would kinda go in, but the second you gas it the thing flies out and grinds. I had the tranny apart and just replaced ALL for safe measure and so i dont have to deal with the other ones going out. This ad is not endorsed by this member. Please register or login to hide this ad.