6th gear grinding

[NYCsubaruBRZ]

Originally Posted by enigmaaron

Almost everyone in this thread is talking about grinding when going into 6th gear, not 4th. Except for the one guy who has also had his transmission replaced.

If you are on your third transmission and it's grinding in 4th again either you are one unlucky guy, there's a rash of bad transmissions (seems unlikely, haven't seen a thread on a 4th gear grinding issue), or - and I mean no offense here - something in your driving habits is causing the problem.

theres other threads about it grinding in other gears.
mine grinds in 4th the most
6th sometimes but high rpm.

not my 1st manual trans. i drive smooth. no offense taken.

[sierra]

I did the same today. Pulled 7,000rpm+ in 2nd and then again in 3rd in a 100kph limit so was over 130kph and slipped it across to 6th and thought I had selected reverse in a 5 speed box!
I wont be doing that again.

[SigmaHyperion]

Skip-Shifting absolutely should not cause any problems, and while a double-clutch up-shift (which should've died out about 50 years with the advent of synchros) may prevent any issues, it absolutely should not be required by any modern transmission. If the transmission can't even stand up to a few thousand miles of basic skip-shifts we're all gonna have problems sooner or later.

GM manuals skip-shift by design. And they're some of the strongest OEM manual transmissions (Tremec T56/6060) available on the market. If they can force a 1->4 upshift, and do it on mild acceleration and unexpectedly to boot (pissing off everyone owner of GM manual vehicles) without damaging anything despite the often heavy loads placed on the transmission as a result, then Subaru's shouldn't be any differerent.

Skip-shifting shouldn't require driver re-training to avoid damaging the transmission (extreme examples like 1->6 or 6->3 withstanding). The fact that the synchros can't take the occassionaly skipped gear is worrisome. If the synchros are fine, and just not allowing the shift because the speeds are too disparate and therefore grinding when attempting to make the shift, I find that extremely odd for an OEM transmission and expect that out of something far more race-prepped. But if they are otherwise in fine condition, then I'll accept it as an odd engineering choice for a mass market vehicle and not be worried about their long-term health. Driver re-training for an engineering decision is fine (though it'll take some time to break the GM/mountains-of-torque-acquired habit of 1-3-6); not for a quality one or one related to someone want to cheap out on a piece of fairly important equipment.

[Speed2th]

Change fluid will always be a good start of fixing grind issues

[SigmaHyperion]

Originally Posted by Speed2th

Change fluid will always be a good start of fixing grind issues

It's also a really good way to get your warranty claim denied in the future if it turns out to be something more. Subaru would be well within its rights to deny a transmission gear issue claim if you were running non-OEM spec MT fluid.

Unless you're just putting in OEM fluid, which should be wholly unnecessary with the limited mileage that anyone complaining has on their cars.

[BRianZ]

Originally Posted by SigmaHyperion

It's also a really good way to get your warranty claim denied in the future if it turns out to be something more. Subaru would be well within its rights to deny a transmission gear issue claim if you were running non-OEM spec MT fluid.

Unless you're just putting in OEM fluid, which should be wholly unnecessary with the limited mileage that anyone complaining has on their cars.

I was also told this point blank by the lead technician at my dealer.


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[zinithin]

6600km on my car and shifting from 4th to 6th around 4500 rpm I'll get a grind. Keep in mind the clutch is fully depressed. I'm going to try 5th 4500rpm to 6th. If it grinds then I'm taking it in. As far as I can tell it's only around 4500rpm which I find strange. If my rpm is higher then I have no grind. Why would it grind at just that rpm? If I knew 6th gear was made of playdoe I'd never use the silly thing.

[Maz]

I am experiencing the same issue. ill bring it up with the dealer tomorrow.

[zinithin]

5th to 6th grind for the first time. Seems like it's getting progressively worse. I'll have to take it in. I'm not skipping gears.

[brznoob]

Mine has started to do the same. I don't skip gears. Shifting from 5 to 6 at high rpms there is some grinding noise/vibration. I'm at 4800 miles. Should I take my car in then?

[enigmaaron]

Originally Posted by zinithin

5th to 6th grind for the first time. Seems like it's getting progressively worse. I'll have to take it in. I'm not skipping gears.

Originally Posted by brznoob

Mine has started to do the same. I don't skip gears. Shifting from 5 to 6 at high rpms there is some grinding noise/vibration. I'm at 4800 miles. Should I take my car in then?

Don't shift from 5 to 6 at high rpms. I get a grind also if do. But 6 shouldn't really be used for hard acceleration anyway, get to speed in 5th, then shift to 6 for cruising economy.

[brznoob]

It only happens at 4.5k or higher. How come the manual doesn't mention anything? This can't be right. I know 6 is the overdrive but I don't use it for hard acceleration . I get up to the speed I want on 5th and then shift to 6th but if I'm already over 4500 rpm you can hear/feel the rather slight grinding when shifting to 6th even when the clutch is fully depressed. I asked a Subaru tech today and told me to take it in. That might be that the 6th gear synchro is going bad

[sierra]

This problem has been there since day one and you would think the factory would have modified the synchros by now?

[Pegasus]

Same problem as the rest, shift from high rpm to 6th = grind. Just noticed it the first time a week or so ago. Taking it in.

I hope the trans on these don't suck. But I will hang in with FR-S.