SMG to Manual Swap

[xansabi]

If I was going to get a shitty manual swap I would have just done it myself.

Hey man, my DIY SMG -> 6MT swap wasn't shitty 😂😂😂

[sapote]

from the driver position, if i try to go into 1st and 2nd (|) it doesnt go in at all. I need to move my elbow, in order to try and shift.

This doesn't help anyone to understand the issue of the gear box. Eveyone has different elbow position when shifting gears. Don't use your arm as a reference but refer to the position of the shift knob, i.e. "to get to 1/2 gate, the shift knob needs to move further to the left (or close to the center straight up, I don't know). There are 2 detents when shifting 1/2 and R: the first softer detent hits the stop for 1/2, and pushing further to enter the 2nd detent for R. Do you think you need to enter partially to the 2nd detent for 1/2?

[efrtysx]

What shop is this?

Why were they so quick to say it was an "internal issue" instead of taking the car back in to properly diagnose your complaint?

Do you know if they used your original bell housing or swapped it?

It was the original housing. You know what, I was going to live with it. But then I thought hell no! I took it to a shop to get it done 100% right. If I was going to get a shitty manual swap I would have just done it myself. I took it back to them yesterday, hopefully they do something about it.

[efrtysx]

If it's the original transmission, and it shifted properly when it was a SMG, it should shift properly now.

They F'd something up somewhere.

Exactly! Car was shifting perfectly fine before I took it. Whole reason I got the manual swap was because the PUMP was failing. Never had any issues shifting into gears.

[sapote]

Aligning the detent holes to the center points of those dowels places the detent in the correct location so the 1-2 and 5-6 shift are straight up and down.

Is this a coincidence or a rule? Only the inside edge of the dowels function to stop the shifter at the precise position for R or 5/6 gate, not their centers. They could just use smaller dowels for this, then their centers would be way off toward the inside edge of the sleeve holes.

[gheorghe]

the dowels "A" and "B"? Why do you think the drilled hole center need to be lined up with the center of the dowel? The function of the dowel: "A" to stop the shifter passing the R gear and "B" to stop passing 5/6 gate. I don't see the logical connection of the detent sleeve holes and the dowels.

Yes, those are the dowels I was referring to. Aligning the detent holes to the center points of those dowels places the detent in the correct location so the 1-2 and 5-6 shift are straight up and down.

[RC Fresh]

What shop is this?

Why were they so quick to say it was an "internal issue" instead of taking the car back in to properly diagnose your complaint?

Do you know if they used your original bell housing or swapped it?

[1000hp]

If it's the original transmission, and it shifted properly when it was a SMG, it should shift properly now.

They F'd something up somewhere.

[sapote]

Correct, the center line of the holes should align with the center point of each dowl that is pressed into the bellhousing.

the dowels "A" and "B"? Why do you think the drilled hole center need to be lined up with the center of the dowel? The function of the dowel: "A" to stop the shifter passing the R gear and "B" to stop passing 5/6 gate. I don't see the logical connection of the detent sleeve holes and the dowels.

[efrtysx]

I ran into the exact same issue during my SMG to 6-speed swap. The root cause was an off-center detent bore. In my case, it happened because I didn’t properly align the Bridgeport mill during bell housing machining.

It bothered me enough that I pulled the transmission back out and took it to a professional machine shop. They measured it with precision gauges and confirmed the bore was slightly misaligned. The fix was a custom detent pin machined to compensate for the offset.

By the time it was machined, hardened, and everything sorted out, it would’ve been cheaper to source a manual bellhousing from a wrecked M3. That said, it now shifts like a factory car.

Good luck but if you want it to shift properly you'd either have to take the route I did or find another bell housing.

Wow that sounds like such a hassle. I’m sorry u had to go through that.

[efrtysx]

1) Too subjective from your description. Let's compare it with a "normal" or factory box: how much you need to pull to the left for 1/2 gears relative to 3/4 position? where is your 3/4 position vs "normal" box?

2) The required "deep angle" to get to 1/2 gears have nothing to do with the internal synchros condition.

You know what, from the driver position, if i try to go into 1st and 2nd (|) it doesnt go in at all. I need to move my elbow, in order to try and shift. (\) Every other gear functions properly. I’m thinking they made a mistake with one of the detents.

[gheorghe]

This drawing has a problem: no reference to the centers of the new drilled holes. Do people just use the "holes" outside casting to find the bores centers? Casting is not precise though.

Correct, the center line of the holes should align with the center point of each dowl that is pressed into the bellhousing. When I did mine, I pre drilled the cast holes to sight those dowels but i messed up the setting when I enlarged the holes to their final diameter. You don't have to be off by much to mess up the 1-2 shift

[sapote]

I ran into the exact same issue during my SMG to 6-speed swap. The root cause was an off-center detent bore. In my case, it happened because I didn’t properly align the Bridgeport mill during bell housing machining.

It bothered me enough that I pulled the transmission back out and took it to a professional machine shop. They measured it with precision gauges and confirmed the bore was slightly misaligned. The fix was a custom detent pin machined to compensate for the offset.

By the time it was machined, hardened, and everything sorted out, it would’ve been cheaper to source a manual bellhousing from a wrecked M3. That said, it now shifts like a factory car.

Good luck but if you want it to shift properly you'd either have to take the route I did or find another bell housing.

This drawing has a problem: no reference to the centers of the new drilled holes. Do people just use the "holes" outside casting to find the bores centers? Casting is not precise though.

[gheorghe]

H 1st and 2nd gear gets stuck as soon as I try to shift. I need to shift at an angle to make sure it goes straight into 2nd gear. I hate customers that are super picky and critical about everything, and I hate even bringing it up. But I can’t live with it. It’s super bad. I wouldn’t care if it was 5th or 6th gear, but it’s incredibly ridiculous to even drive the car. They’re telling me it’s an internal issue and not related to the actual bellhousing machining/installation.

I ran into the exact same issue during my SMG to 6-speed swap. The root cause was an off-center detent bore. In my case, it happened because I didn’t properly align the Bridgeport mill during bell housing machining.

It bothered me enough that I pulled the transmission back out and took it to a professional machine shop. They measured it with precision gauges and confirmed the bore was slightly misaligned. The fix was a custom detent pin machined to compensate for the offset.

By the time it was machined, hardened, and everything sorted out, it would’ve been cheaper to source a manual bellhousing from a wrecked M3. That said, it now shifts like a factory car.

Good luck but if you want it to shift properly you'd either have to take the route I did or find another bell housing.

[sapote]

1) 1st and 2nd gear gets stuck as soon as I try to shift. I need to shift at an angle to make sure it goes straight into 2nd gear. It’s super bad.
2) They’re telling me it’s an internal issue and not related to the actual bellhousing machining/installation. How could a 420g SMG transmission possibly have bad syncros, or internal wear? Any advice on what it could be ?

1) Too subjective from your description. Let's compare it with a "normal" or factory box: how much you need to pull to the left for 1/2 gears relative to 3/4 position? where is your 3/4 position vs "normal" box?

2) The required "deep angle" to get to 1/2 gears have nothing to do with the internal synchros condition.