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Discussion Starter #1
2004 E46 325ci Automatic ZF Transmission.

So I've rounded four of the T27 bolts that hold the transmission oil pan. They're currently soaking in PB and will attempt to remove them in the next coming days.

I'm wondering which technique will be the best in order to remove them. I've read that people cut into the head of the bolts with a dremel and hammer it with a flathead to get it to turn. People have also mentioned drilling the head of the bolt straight off with a brand new drill bit. I'm leaning more towards the drilling option.

Can anyone shed some light if they have experienced this before? Drilling the heads off seems a lot simpler but I don't want to wind up in a situation where I can't grip and unscrew the thread that remains.

Hammering with a flathead after slitting with a dremel seems like the safer option but I'm worried they won't come out that easily as the bolts that I managed to get off were VERY tight. Some of them were already starting to round but thankfully cracked off after some PB.

Open to further suggestions.
 

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'03 325iT Mystic Blau
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Those bolts are Loctited, so could still be difficult to turn out after heads are cut off, and there won't be much screw to grab hold of once the pan is dropped. There's a good chance that you won't be able to get them out to put the car back together. I'd go with slotting the head and using a screwdriver before I did that.

The first thing that I would try though is to whack the heads with a hammer and punch. This has a shock effect to help break loose a stuck fastener and can also peen the stripped head back closed tightly enough that the tool can grip it again. I work on CNC milling machines and use this on stripped Allen fasteners all the time, should work on Torx as well.
 

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//Binary is in my DNA
2002 BMW 325i
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Those bolts are Loctited, so could still be difficult to turn out after heads are cut off, and there won't be much screw to grab hold of once the pan is dropped. There's a good chance that you won't be able to get them out to put the car back together. I'd go with slotting the head and using a screwdriver before I did that.

The first thing that I would try though is to whack the heads with a hammer and punch. This has a shock effect to help break loose a stuck fastener and can also peen the stripped head back closed tightly enough that the tool can grip it again. I work on CNC milling machines and use this on stripped Allen fasteners all the time, should work on Torx as well.
Striking the head straight on is always my go-to for stubborn bolts. Almost always have to do this on the brake rotor screws.
 

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Discussion Starter #4
Those bolts are Loctited, so could still be difficult to turn out after heads are cut off, and there won't be much screw to grab hold of once the pan is dropped. There's a good chance that you won't be able to get them out to put the car back together. I'd go with slotting the head and using a screwdriver before I did that.

The first thing that I would try though is to whack the heads with a hammer and punch. This has a shock effect to help break loose a stuck fastener and can also peen the stripped head back closed tightly enough that the tool can grip it again. I work on CNC milling machines and use this on stripped Allen fasteners all the time, should work on Torx as well.
I did manage to remove two of the bolts using the hammer and flathead technique, without the dremel. Did take a while though and the remaining four weren’t budging so I stopped for the day.

I’ll give the punch technique a go but I don’t have a punch that’ll fit in between the torx gap so will have to use an attachment from my bit set.

The actual heads are gone I tried hammering in a T30 to try and break them loose but even this is rounding on the remaining four.

Will punch with hammer and slit with dremel. Fingers crossed they crack!
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Have you tried cleaning the inside of the head, carefully clocking in a T30 and hammering it into the head?
The hammering will do two things. Hopefully get a fresh (larger) bite, and shocking the threads.

I'd be doing this before I moved over to more elaborate removal techniques.
 

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Discussion Starter #8
Have you tried cleaning the inside of the head, carefully clocking in a T30 and hammering it into the head?
The hammering will do two things. Hopefully get a fresh (larger) bite, and shocking the threads.

I'd be doing this before I moved over to more elaborate removal techniques.
Yes did try this but to no success. It looks like the bolts have never been touched throughout the lifetime of the car. They are super tight - a lot more than the recommended torque spec for sure.
 

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//Binary is in my DNA
2002 BMW 325i
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Yes did try this but to no success. It looks like the bolts have never been touched throughout the lifetime of the car. They are super tight - a lot more than the recommended torque spec for sure.
I just did mine last year and the torque is 8 ft/lbs. Not sure why yours are so tough.
 

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A previous post mentioned the bolts have thread locker. If that's the case, then heating the bolt should soften the thread locker. Then you can force-fit a T30 bit, and cross your fingers.
 

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Discussion Starter #11
Thanks everyone. Managed to get the four seized bolts out with the trusty hammer and flathead technique. They were a b*tch. Dremel wouldn’t reach the bolts as there wasn’t enough clearance. The reason for this job was because the gearbox was in limp mode. It’s still unfortunately in limp mode but after the fluid and filter replacement my solus pro is now only spitting out one code - it was throwing out a bunch of random gearbox related codes which I think the new fluid fixed. My only option would be to take it to the stealership as I am physically and mentally exhausted. Does anyone have any further suggests? Or is the gearbox shot and not worth the trip down to BM. Will most likely break her for spares and repairs if she’s gone. Which is a real shame :(

921944
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Looks like a bad solenoid. I wouldn't know more until I'm back at the shop.
 

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If what you’re talking about is linked to the solenoid repair kit available on eBay then my answer would be yes. I am far from transmission savvy though and I’m not sure I have the capacity to do this.

The car has been playing up since late last year so my patience is wearing thin.
 

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'03 325iT Mystic Blau
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If what you’re talking about is linked to the solenoid repair kit available on eBay then my answer would be yes. I am far from transmission savvy though and I’m not sure I have the capacity to do this.

The car has been playing up since late last year so my patience is wearing thin.
It doesn't look that difficult, not much more involved than simply changing the trans fluid.
 

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Hammering with a flathead after slitting with a dremel seems like the safer option but I'm worried they won't come out that easily as the bolts that I managed to get off were VERY tight.
A little late but keep this technique in mind: don't just hammering a dumb screwdriver, but use a smart screwdriver like this instead. As you hammering it the bit will rotate CCW (or CW if selected) to loosen while the impulse force helps to keep the bit from popping out.
 

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Discussion Starter #17
Isn't there a solenoid that fails frequently enough on the ZF that many people replace them preventatively while they've got the pan off?
Looks like a bad solenoid. I wouldn't know more until I'm back at the shop.
Did you find more back at the shop?

Update: the car runs fine for a while when I start it in neutral but goes back into limp mode shortly after once driven down the road.
 

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Did you find more back at the shop?

Update: the car runs fine for a while when I start it in neutral but goes back into limp mode shortly after once driven down the road.
Sorry I do not. Nor do I have anything in my archives.
If you have a look at the above pdf. document Page # 19 shows the EDS valves and the MV valves.
Then on page #29 there is a brief description of the MV1, 2 & 3.
I am bereft of the exact location of where these are on the valvebody. I would endeavor to swap MV1 with MV3. Refill and see if the fault moves. (Tantamount to an ignition coil swap.) if it does, you know that MV1 needs replacing.
 

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Discussion Starter #20
Had her parked up on a curb at an angle the past few days, started her up and the limp mode was gone. Drove perfectly down the road but soon whistled it’s way back into the limp. Not sure if the angle I had it at did some magic on the magnetic valves/solenoids. Oh, and the button that brings the wing mirrors down into place didn’t move the passenger side back. I had to move it myself with some force. Strange. I’m going to get quotes on a recondition. The pdf is good but doesn’t provide enough to go after the valves myself.
 
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