2024 MT 2ND gear grinds

[harutora]

Are you pulling straight back into 2nd? You might be getting 2nd gear lock out, which I used to get. This is my 1st BMW manual, and it is a little finicky compared to previous manuals I’ve owned. Once I got used to it, it did improve. What significantly helped was the Auto Solutions shift kit, it made the shifting feel more precise, and also less rubbery feel.

I am pulling straight back yes, but I’m not slamming it into gear by any means, I’m gentle and precise with my shifting, albeit quick. I’ll have to look into that shift kit after I take it to the dealer.

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[lucky phil]

I am pulling straight back yes, but I’m not slamming it into gear by any means, I’m gentle and precise with my shifting, albeit quick. I’ll have to look into that shift kit after I take it to the dealer.

The shift kit isn't going to help your issue.
Phil

 

[harutora]

Bleed the clutch
Phil

It's a new car, shouldn't the dealer warranty it?
I COULD bleed the clutch but it doesn't seem like it's slipping or spongy, and I haven't done anything to it to get air into the system. I haven't even deleted the CDV yet.

 

[lucky phil]

It's a new car, shouldn't the dealer warranty it?
I COULD bleed the clutch but it doesn't seem like it's slipping or spongy, and I haven't done anything to it to get air into the system. I haven't even deleted the CDV yet.

Here's a concept for you. It's an oldie but a goodie. If you want something done right then do it yourself. The Supra has a non typical clutch feel for a modern manual with a diaphragm spring pressure plate. It feels pretty consistent pressure through the whole travel without the over centre feel most have, like an old coil spring PP so determining "sponginess" is very difficult. How far off the floor does the clutch hit it's "friction point""?
Basic troubleshooting for shifting issues #1 bleed the clutch and see if it's got any air in it and if it makes a difference. Then move onto the more painful stuff if you need to like checking the gearbox oil level and changing out the gearbox oil. After that it starts getting complicated but thats all stuff you can do yourself.
The dealer mechanics? Spare me.
Phil

 

[splv]

Take it to the dealership to get it fixed under warranty. Don’t eff around and find out that they won’t take responsibility after your Cheetos-covered fingers have me up in thurr.

 

[lucky phil]

Take it to the dealership to get it fixed under warranty. Don’t eff around and find out that they won’t take responsibility after your Cheetos-covered fingers have me up in thurr.

You're right. I forgot it's that simple. How silly of me.
Phil

 

[splv]

You're right. I forgot it's that simple. How silly of me.
Phil

It’s ok. You’re no Dr Phil. Basic Phil can’t know everything, you Phil me?

 

[5150.MKV]

Everytime I’ve tried to race my buddies for fun, it always grinds and locks me out of 2nd, ruins the fun completely.

I have experienced this multiple times as well unfortunately... don't have much to add other than it looks like people in the BMW forums experience similar problems in their M cars and the general consensus is to shift earlier. Tbh I always contributed it to Driver Mod Issue but in my FoRS I never had this issue, and I consistently slammed the gears in that car. Total buzzkill when my friends FRS starts catching up/pulling away from me because 2nd gear is being stubborn. +1 for the Auto boys I guess

 

[harutora]

Here's a concept for you. It's an oldie but a goodie. If you want something done right then do it yourself. The Supra has a non typical clutch feel for a modern manual with a diaphragm spring pressure plate. It feels pretty consistent pressure through the whole travel without the over centre feel most have, like an old coil spring PP so determining "sponginess" is very difficult. How far off the floor does the clutch hit it's "friction point""?
Basic troubleshooting for shifting issues #1 bleed the clutch and see if it's got any air in it and if it makes a difference. Then move onto the more painful stuff if you need to like checking the gearbox oil level and changing out the gearbox oil. After that it starts getting complicated but thats all stuff you can do yourself.
The dealer mechanics? Spare me.
Phil

I know what you're saying but it's brand new, transmission has NEVER been touched by a dealer. How would air be introduced into the system?

 

[FLtrackdays]

I know what you're saying but it's brand new, transmission has NEVER been touched by a dealer. How would air be introduced into the system?

Time for a nice race clutch and move on

 

[lucky phil]

I know what you're saying but it's brand new, transmission has NEVER been touched by a dealer. How would air be introduced into the system?

Umm, because cars aren't always assembled perfectly at the factory. Look it's a process of troubleshooting elimination. You do the no cost simple stuff and work your way by process of elimination to the possibility of a more serious problem That's what the dealer will do if push comes to shove and you can convince them to do anything at all.
What do you want a dealer to do? start throwing new transmissions and/or clutches at it first up?
I still think part of the problem here is if you want a car to drag people off at the lights then buy the Auto. The manual is about what happens from 2nd gear up and the engagement of driving a manual sports car on sports car roads not the predominantly US obsession with 1/4 mile times and stoplight racing.
Phil

 

[Psygnosis7]

I also have a 24 MT and shortly after getting it I shifted too quick and did a 2nd gear grind, but I also wasn't terribly surprised because I've also had it happen in my 04 Z4. It still happens sometimes but not enough for me to think something is wrong with the car.

 

[lucky phil]

The issue here is that the Supra 6 speed manual gearbox has a very large ratio jump between 1st and 2nd gears. This obviously makes the job of the syncro much, much harder. So for example the Supra ration jump 1st to 2nd is 4.110 to 2.315 a jump of 1.76 in the ratio. For comparison of a similar duty gearbox the Tremec T56 or T56 Magnum both have a 1st to 2nd ratio jump of .88 and .87 for the two ratio options available ( close and wide ratio) The Supra ratio jump is almost twice the difference to the Tremec. So for a similar medium duty gearbox the Supras 2nd gear syncro has a much bigger job to do. It's just never going to shift fast 1st to 2nd as say a Tremec. It's just a characteristic of this gearbox with the wide 1st to 2nd gear ratio gap.
Running the taller auto diff ration would probably help it I believe as the higher road speed and corresponding gearbox rotational speed usually helps the shifting to a degree but it's probably never going to be a slick 1st to second change. Short shifting 1st to second is the answer and using the big low rpm torque from second up is the answer to driving this car. Stoplight racing is the Autos forte.

 

[shaloot]

I have not experienced any sounds, grinding, or resistance to get into any gear so far.
However I don’t drag my manual like it’s a 90’s civic at a red light either

edit: what Phil said above me makes perfect sense. Meaning the large ratio jump from 1st to second. Prolly need to give it more time between 1st to second shift,

absolutely love this car as a manual and would never own the auto but obviously the ZF8 is far more fleshed out as a drag friendly trans

 

[splv]

The issue here is that the Supra 6 speed manual gearbox has a very large ratio jump between 1st and 2nd gears. This obviously makes the job of the syncro much, much harder. So for example the Supra ration jump 1st to 2nd is 4.110 to 2.315 a jump of 1.76 in the ratio. For comparison of a similar duty gearbox the Tremec T56 or T56 Magnum both have a 1st to 2nd ratio jump of .88 and .87 for the two ratio options available ( close and wide ratio) The Supra ratio jump is almost twice the difference to the Tremec. So for a similar medium duty gearbox the Supras 2nd gear syncro has a much bigger job to do. It's just never going to shift fast 1st to 2nd as say a Tremec. It's just a characteristic of this gearbox with the wide 1st to 2nd gear ratio gap.
Running the taller auto diff ration would probably help it I believe as the higher road speed and corresponding gearbox rotational speed usually helps the shifting to a degree but it's probably never going to be a slick 1st to second change. Short shifting 1st to second is the answer and using the big low rpm torque from second up is the answer to driving this car. Stoplight racing is the Autos forte.

Excellent explanation, Phil. I Phil you on that one!

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