[Geighty7]

Originally Posted by dienstag

If your are sure your car over-rev'd, AFAIK there is no other cause than a misshift. Rev match will not over-rev your engine, and certainly not if it thinks you're upshifting. And you couldn't over-rev it with the throttle due to rev limiter. I am not a BMW guru so maybe there's something I'm missing, but I cannot see how this car can be over-rev'd other than mechanically by picking the wrong ratio.

Not sure. It was a straight down shift at 100mph. You’d have to be some sort of dumb to go from 3 to 2 even if you’re speed shifting and “in the zone”. If it was a missshift, my car wouldn’t be driving right now, which it is.

[eluded]

They don't call it the money shift for nothing. It happens

Originally Posted by Geighty7

Not sure. It was a straight down shift at 100mph. You’d have to be some sort of dumb to go from 3 to 2 even if you’re speed shifting and “in the zone”. If it was a missshift, my car wouldn’t be driving right now, which it is.

[fanofbmwe46]

Pretty sure I still have my CDV if you want to buy it. I’m trading my G80 for a G87 in a few weeks and would be happy to sell the CDV then just to ensure no reason why I would need it. $25 shipped should cover my time to go to the post office.

I agree though that I don’t think they would look at that in detail. I think they would just try to replicate a few times and then would authorize a replacement trans.

[Geighty7]

Originally Posted by eluded

They don't call it the money shift for nothing. It happens

I don’t think you’re understanding. I did not money shift. I went from 3 to 4.

[chris719]

Just take the clutch stop out, your call on cdv but it means a new slave cylinder.

[two_three_two]

Originally Posted by Geighty7

Hey guys,

Please help weigh in here-

no offense big dog but you should probably leave your CDV in after you sort this out. probably could have been avoided based on your driving style in the recent past

[Montaver]

Depending on how much the clutch stop reduces the travel, you may not be disengaging your clutch fully on shifts.

[KevM2]

Originally Posted by Montaver

Depending on how much the clutch stop reduces the travel, you may not be disengaging your clutch fully on shifts.

I’ve heard this also from other posts on this forum. The clutch stop is likely the culprit

[minn19]

Geighty7, I re-read your OP and I think you went into second by accident. I can’t think of any other way it activates revmatch and or over revs/plus the locking of the tires. Obviously this doesn’t happen if you go into 4th or 6th. Nor does it happen if it locks you out of 4th, it would pop back into neutral wouldn’t it? Thats what has happened to me in the past with MTs when it locks out of a gear.

[Geighty7]

Originally Posted by minn19

Geighty7, I re-read your OP and I think you went into second by accident. I can’t think of any other way it activates revmatch and or over revs/plus the locking of the tires. Obviously this doesn’t happen if you go into 4th or 6th. Nor does it happen if it locks you out of 4th, it would pop back into neutral wouldn’t it? Thats what has happened to me in the past with MTs when it locks out of a gear.

I got it checked out today- data logs do not show any weirdness. No money shift, my engine is completely fine so no way I went into 2nd and spun anything.

Since I have a CDV delete, we chopped it up to the transmission is just inferior for the engine coupled with my speed shifting. The fork got hung up in gear, and since rev match works both down shift and upshift, in the split second I did not know when I was “in between gears” I gave her beans which sent RPM’s flying half in gear and half out, chewing up my 4th gear.

Thankfully these things are bullet proof. I will likely drain the diff and find some glitter, but no concern from the foreman nor my shop.

To prevent it, I need to either be slower on my release as the trans doesn’t like speed shifting, or go with a new clutch or change the fluid to something less or more viscous.

[Geighty7]

Originally Posted by Montaver

Depending on how much the clutch stop reduces the travel, you may not be disengaging your clutch fully on shifts.

Brought that up, it’s a non issue after foreman drove my car for a bit.

[Geighty7]

Originally Posted by two_three_two

no offense big dog but you should probably leave your CDV in after you sort this out. probably could have been avoided based on your driving style in the recent past

That’s also true. I was speed shifting like I was in a vette lol. This trans hasn’t been upgraded in a long time as they are getting rid of manuals. The transmission basically doesn’t mesh well with s58 under super high load and aggressive speed shifting.

I will likely upgrade my clutch.

[D.Yooras]

Originally Posted by Geighty7

Not sure. It was a straight down shift at 100mph. You’d have to be some sort of dumb to go from 3 to 2 even if you’re speed shifting and “in the zone”. If it was a missshift, my car wouldn’t be driving right now, which it is.

Sounds like a bent shift fork to me. Pretty typical of these ZF transmissions. It would appear that they make the shifts forks soft for a smoother shifting feel but it makes them easy to bend, especially when shifting aggressively. A bent shift fork causes the selection slider to over-engage one gear (usually the opposite gear of the one the bad shift was thrown to) and under-engage the other. Additionally, the shift fork usually won't bend straight so it will partially engage one/both of the gears on that leg of the transmission.

The bad news is, to fix it means a new transmission which is expensive and not likely to covered under warranty unless BMW's goodwill division is feeling generous. The good news is, it is "possible" to bend a bent shift forks back somewhat to correct the problem.

I'd dealt with a bent 1-2 shift fork that was fine on engaging 1st gear but the 2nd gear shift was not great. Since I knew the direction the fork was bent, I was able to slowly bend the shift fork back over time using trial and error. 1-2 shift is very good now 8.5/10 from my experience with these transmissions, started at 6/10.

Trick is, you have to know which way the fork is bent, otherwise you could make a bad situation worse. With 3rd gear, it's a bit tricky because it could be bent from an aggressive 2-3 shift or 3-4, with each one being the opposite direction.

[BroDoze]

I tend to drive manuals very hard - slam-shifting n what not. That’s kinda how they’re meant to be driven.
My 2005 6MT STi was a freaking slam-shifting rockstar. Triple-cone 2nd gear synchros, 3rd n 4th. Bulletproof. Widely known as one of the best. I got very used to that transmission.
I then moved “up” to BMWs and their 6MTs. Woah, not so fast. I had to seriously slow my roll or I’d be grinding everything to hell. It drove me nuts. I found it fairly tough to drive them smooth but fast. Got used to it, but I never loved it. Made me miss my STIs.

[Geighty7]

Originally Posted by BroDoze

I tend to drive manuals very hard - slam-shifting n what not. That’s kinda how they’re meant to be driven.
My 2005 6MT STi was a freaking slam-shifting rockstar. Triple-cone 2nd gear synchros, 3rd n 4th. Bulletproof. Widely known as one of the best. I got very used to that transmission.
I then moved “up” to BMWs and their 6MTs. Woah, not so fast. I had to seriously slow my roll or I’d be grinding everything to hell. It drove me nuts. I found it fairly tough to drive them smooth but fast. Got used to it, but I never loved it. Made me miss my STIs.

That’s literally what the foreman said today at bmw lol.

[Geighty7]

Originally Posted by D.Yooras

Sounds like a bent shift fork to me. Pretty typical of these ZF transmissions. It would appear that they make the shifts forks soft for a smoother shifting feel but it makes them easy to bend, especially when shifting aggressively. A bent shift fork causes the selection slider to over-engage one gear (usually the opposite gear of the one the bad shift was thrown to) and under-engage the other. Additionally, the shift fork usually won't bend straight so it will partially engage one/both of the gears on that leg of the transmission.

The bad news is, to fix it means a new transmission which is expensive and not likely to covered under warranty unless BMW's goodwill division is feeling generous. The good news is, it is "possible" to bend a bent shift forks back somewhat to correct the problem.

I'd dealt with a bent 1-2 shift fork that was fine on engaging 1st gear but the 2nd gear shift was not great. Since I knew the direction the fork was bent, I was able to slowly bend the shift fork back over time using trial and error. 1-2 shift is very good now 8.5/10 from my experience with these transmissions, started at 6/10.

Trick is, you have to know which way the fork is bent, otherwise you could make a bad situation worse. With 3rd gear, it's a bit tricky because it could be bent from an aggressive 2-3 shift or 3-4, with each one being the opposite direction.

Nothing feels bent. Everything feels normal to drive same as before it happened. How would you know if it’s bent? Is there tell tale signs?

[D.Yooras]

Originally Posted by Geighty7

Nothing feels bent. Everything feels normal to drive same as before it happened. How would you know if it’s bent? Is there tell tale signs?

A couple of things to look for:

Feeling a notchy feeling about halfway through the shift when shifting normally. Generally, these transmissions are made to have little "click/clack" feeling when engaging syncos on a straight transmission.

If you hold the shifter very softly (not to one end or the other just let it stay in the gear you're in) roll on and off throttle progressively. It has to be really small inputs on/off for this to work. You're looking for the shifter to move (it'll be slight) back and forth while you're changing on/off throttle position. The bent shift fork will usually move back and forth during reversal in the gear that it's bent away from (not engaging fully) because it's causing the slider to engage the gear at an angle. When the reversal happens the slider is able to push against the shift fork which will cause sublet movement.

For example, the car I was dealing with had the 1-2 shift fork bent away from 2nd gear and towards 1st. When I tried the above procedure I could feel the shifter move in 2nd gear every time the reversal happened so I knew the fork was bent away from 2nd gear.

[minn19]

Originally Posted by Geighty7

I got it checked out today- data logs do not show any weirdness. No money shift, my engine is completely fine so no way I went into 2nd and spun anything.

Since I have a CDV delete, we chopped it up to the transmission is just inferior for the engine coupled with my speed shifting. The fork got hung up in gear, and since rev match works both down shift and upshift, in the split second I did not know when I was “in between gears” I gave her beans which sent RPM’s flying half in gear and half out, chewing up my 4th gear.

Thankfully these things are bullet proof. I will likely drain the diff and find some glitter, but no concern from the foreman nor my shop.

To prevent it, I need to either be slower on my release as the trans doesn’t like speed shifting, or go with a new clutch or change the fluid to something less or more viscous.

I don’t think there is rev match on the up shift. I have awful rev hang in my 1-2, 2-3 shift in sport throttle. I have to wait for over a second (counted yesterday and today) to let the clutch out otherwise it is very out of sync. It’s better in comfort and if I shift around 2500 RPM, which we know is no fun.

Regardless, glad the motor is fine! And hopefully the transmission isn’t in too rough of shape.

[Geighty7]

Originally Posted by minn19

I don’t think there is rev match on the up shift. I have awful rev hang in my 1-2, 2-3 shift in sport throttle. I have to wait for over a second (counted yesterday and today) to let the clutch out otherwise it is very out of sync. It’s better in comfort and if I shift around 2500 RPM, which we know is no fun.

Regardless, glad the motor is fine! And hopefully the transmission isn’t in too rough of shape.

Yeah turn it off and try shifting fast you can tell there’s a tiny blip at the tale end of the powerband when it’s on vs off.

Thanks, everything seems super normal driving around. Not too concerned, will flush the diff fluid and see what’s up with glitter. Other than that, nothing more I can do if there’s physically no difference.

I wish I could tell bmw to give me a new trans just to be sure, but they won’t do that lol.

[PrickyMcPrik]

Sorry to say bro but you may need to take gear changing lessons from old mate in this vid… don’t forget that little flick at the end now


https://m.youtube.com/watch?v=FLYpHg...Z2luZyBidXM%3D

[Geighty7]

Originally Posted by D.Yooras

A couple of things to look for:

Feeling a notchy feeling about halfway through the shift when shifting normally. Generally, these transmissions are made to have little "click/clack" feeling when engaging syncos on a straight transmission.

If you hold the shifter very softly (not to one end or the other just let it stay in the gear you're in) roll on and off throttle progressively. It has to be really small inputs on/off for this to work. You're looking for the shifter to move (it'll be slight) back and forth while you're changing on/off throttle position. The bent shift fork will usually move back and forth during reversal in the gear that it's bent away from (not engaging fully) because it's causing the slider to engage the gear at an angle. When the reversal happens the slider is able to push against the shift fork which will cause sublet movement.

For example, the car I was dealing with had the 1-2 shift fork bent away from 2nd gear and towards 1st. When I tried the above procedure I could feel the shifter move in 2nd gear every time the reversal happened so I knew the fork was bent away from 2nd gear.

Quick update- I replicated the issue to a T last night and it indeed is going into 2 instead of 4 even with a straight down shift. I am afraid your assumption is correct about a bent shift fork. There’s no other reasoning behind this.

I am currently at dealer now waiting for my rental since I dropped it off. The foreman is working with me to get a warranty new trans and take a look at the engine.

If they don’t warranty, I’ll likely look at other next steps.

[Squidget]

Originally Posted by Geighty7

Quick update- I replicated the issue to a T last night and it indeed is going into 2 instead of 4 even with a straight down shift. I am afraid your assumption is correct about a bent shift fork. There’s no other reasoning behind this.

Oof, I feel bad for you, that sucks. That's a non-trivial repair.

Also, wow, mad props to D.Yooras for pulling that diagnosis out of the air. I am impressed. Bent forks are rare and I never would have thought of that.