Manual 6 speed 10-1200 miles grinding 2nd 3rd shift

[AZ_Ryan]

I don't remember who said it, but one of the famous tuners here mentioned driving in all the modes (normal, slippery, track, sport, etc.) for like, 10 to 30 miles each, so the transmission can "learn," since the s650 transmission is adaptive, apparently.

I did that, and my shifting got better, especially from 2nd to 3rd gear, and it feels tighter, not like I'm shifting through a box of rocks anymore.

He has a manual not an auto.

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[Garcia172]

Not necessarily. Gear speed difference reduces as you upshift through the gears, so it becomes easier for the synchro cones to match speeds.

I understand what you're getting at... that the performance of the synchros become less relevant & necessary as the gear ratios become closer because the gears spinning closer and closer to the same speed.

Technically speaking, you don't need synchros at all, if you shifted you engaged the next gear at the exact rpm necessary. But that's never the case (and very hard to do on a non-sequential helical cut gear box).

And, using your logic, why doesn't it grind on the 1-2 shift since the gear ratio change is the largest of all the gear ratio changes? Why not when you put it into 1st gear from neutral? (which is even larger).

I highly doubt it would/could be a clutch or TO bearing or a master/slave issue because it would be happening in other gears (at a minimum occasionally). Especially because we're talking about a new car, used lightly on the street around town where nothing is heat soaked (like on a race track).

My money is on an internal transmission issue (synchros or something else... but in the trans for sure).

 

[LouG]

I'm not saying it definitively is the problem, it is one of the first things you check when carrying out diagnosis of the issue becuse it is easiest to remedy.
As for which gears it may clash in, all synchro cones aren't created equal, like most things mechanical, often first and maybe second gears have dual cones because of the rotational issue. I don't know if either Mustang manuals have that.
And, yes, I have driven crash boxes. Both non synchro ones, and those unintentionally with totally f**ked synchros.
No rev matching BS when I learned to drive.

 

[Garcia172]

I'm not saying it definitively is the problem, it is one of the first things you check when carrying out diagnosis of the issue becuse it is easiest to remedy.
As for which gears it may clash in, all synchro cones aren't created equal, like most things mechanical, often first and maybe second gears have dual cones because of the rotational issue. I don't know if either Mustang manuals have that.
And, yes, I have driven crash boxes. Both non synchro ones, and those unintentionally with totally f**ked synchros.
No rev matching BS when I learned to drive.

The main point is it's a brand new car, driven casually on street around town with a consistent repeatable grinding on the 2-3 & occasional on the 3-4.

And I'm sure Ford would, for obvious reasons, looks for the low hanging fruit, as we all would.

But with a new car and a warranty, he needs to drop the car off at Ford. It's no me problemo, it's su problemo lol

I've never driven a crash box. I've road raced sequentials with rev matching flat foot shifting/auto blipping rpm matching down shifting/stacked down shifting. As well, sequentials with none of that (for former is much faster and more fun lol). I was surprised to see rpm matching down shifting on these cars (personally, IMO, it's not that good because the engine is pretty slow reving compared to a light weight reciprocating mass/clutch race engine) and relying on that alone better than nothing but still to slow down shift quickly. My guess was that Ford did it to easy up on syncho wear (warranty) for people not good at heal-toe.

And unfortunatly in GT class racing... it's the have & the have-nots. Manual shifting or even sequential w/o flat foot shifting/auto blipping is absolutely slower around the track.

 

[LouG]

I might have a few years on you. Crash boxes are great fun, but slow as a wet weekend.

 

[Garcia172]

I might have a few years on you. Crash boxes are great fun, but slow as a wet weekend.

Past my pay grade....B The crash boxes... I thought their Muncie something lol back in the day. No idea how they drove I read about a few of them here and there in magazines but no experience at all. I think it was a muscle car thing. By the way still love muscle cars lol

 

[pitmomjess]

It's not a box of rocks, but it is notchy, especially when cold. For me, 2nd and 5th are the worst. I test drove another DH and it was also notchy.

It gets much better when hot, but still not silky smooth. But I don't expect that in a high performance transmission.

Keep in mind that Ford puts in very robust synchronizers because some people will drag race their car and shift very quickly, which is pretty tough on the tranny.

I had this on a 2022 HPP Ecoboost with the MT-82. I changed the transmission fluid to BG, installed a steeda short throw shifter, tranmission mount bushing, and shifter bushing...still had hard time getting into 2nd gear. When it was really cold outside, I had to skip second altogether. Traded it for a 2024 5.0 automatic and haven't looked back.

 

[LouG]

Past my pay grade....B The crash boxes... I thought their Muncie something lol back in the day. No idea how they drove I read about a few of them here and there in magazines but no experience at all. I think it was a muscle car thing. By the way still love muscle cars lol

I had the great fortune to drive a Ferrari Dino 246 way back in the day. They said those things were like an arthritic old fart when cold. They weren't wrong, it was like using a crash box until the oil warmed up a few degrees. Probably wouldn't be a problem with modern gear oils.

 

[Ciulster]

My gearbox was pretty stiff getting into gear for probably the first 2k miles or so. Now that she's over 12k miles it's pretty good. Little bit notchy and "rocky" feeling going in like a little bit of a rumble felt in the hand but never any noise. Noise outside of hearing the shift lever rattle and think into place during a shift or audible grinding noise is immediate no-no.

My 1-2 shift has always been stiffer and more notchy than the rest especially if I granny shift. Above 4000rpm it's butter though it just wants to be revved out. All other gears are almost perfect now too. I'd say if it doesn't resolve in another 1000 miles or gets worse take it in for an opinion.

 

[BimmerDriver]

My gearbox was pretty stiff getting into gear for probably the first 2k miles or so. Now that she's over 12k miles it's pretty good.

I will add that since my earlier post and adding a few miles onto the car, it's getting better. Everything needs a bit of break-in and heat cycles.

I had the great fortune to drive a Ferrari Dino 246 way back in the day. They said those things were like an arthritic old fart when cold. They weren't wrong, it was like using a crash box until the oil warmed up a few degrees. Probably wouldn't be a problem with modern gear oils.

I test drove a 355 a few years back. It was, by far, the worst transmission I have ever experienced, which includes a 3500 chassis 200+K worn-out Hertz truck and beat-on race cars. The salesman quipped "this is one of the best shifting Ferraris I've driven" and I just kept my mouth shut, because I couldn't imagine paying that kind of money for that kind of garbage.

 

[Paul's stable]

I think that my MT is a wee bit notchy-feeling when cold, but not a box of rocks. It improves as it gets up to operating temperature. The MT in my Honda Civic is smoother, though it's only dealing with 1/3 the horsepower. I wonder what the Tremec MT in the Dark Horse is like.

Mine is awesome smooth as butter I love it so much I put a Tremec 6 spd in my 06 Mustang GT. They both are great.

 

[HighFlyer]

Update. it’s got cold and snowy where I live between that and my work deciding that I need to bounce around the country I have not been able to get the car in to the dealer.

just a little more info when I’ve been able to drive the car. 2500-3000 around town shift seems to be the trouble spot. Double clutching into gear no issue, but it’s a 25 not a 53 Chevy pickup.
Thanks for all of your responses. When I get an answer I’ll post it

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