Transmission Drain Plug

[Bill97]

New here  On my new2me 97 1100rt the recessed transmission drain plug has a stripped hex socket.  I have a new plug from Break My Wallet and now the problem is how to remove the old one.  I would like to change the transmission oil some day soon as I've put 40k km on it since the previous owner replaced the clutch. I would assume the dealer would have done something with the oil then .... but I can;t be sure.  Any suggestions from the gurus are welcome.  Be a shame to lose it to a transmission failure after an epic ride to James Bay !

[dirtrider]

14 minutes ago, Bill97 said:

New here  On my new2me 97 1100rt the recessed transmission drain plug has a stripped hex socket.  I have a new plug from Break My Wallet and now the problem is how to remove the old one.  I would like to change the transmission oil some day soon as I've put 40k km on it since the previous owner replaced the clutch. I would assume the dealer would have done something with the oil then .... but I can;t be sure.  Any suggestions from the gurus are welcome.  Be a shame to lose it to a transmission failure after an epic ride to James Bay !

 

Afternoon Bill97

 

You need to be creative & willing to change direction as the job unfolds__

 

My first choice is usually to find a torx bit that is slightly larger than the existing hex, then drive that into the hex with a hammer (then try to remove  plug)

 

If that fails then I try  to find a standard sized hex driver  bit that is slightly larger than the existing hex, then drive that into the hex with a hammer (then try to remove  plug). If the next size up (usually a standard not a metric)  won't drive in then use a grinder on it until it will drive in (then try to remove  plug).

 

Next, I will sometimes drill a small shallow hole in the outer ring of the plug (not all the way through) then use a punch at an angle in that hole  to drive the plug in the removal direction.

 

There are other more complicated ways to try but those are more for the more experienced machinist type.

 

You can also remove the top (fill) plug then get some help & lay the bike on it's side to drain most gear oil out.

 

 

[Bill97]

Thanx for the quick reply ! After seeing your sage advice elsewhere I was hoping for your post. I was considering your first 2 suggestions but the shroud / funnel casting around it makes #3 impossible [or at least to what I see]  I suspect it will be a 'winter' task.  If 1 & 2 don't work perhaps siphoning it will.  

[The Fabricator]

I have had success by smacking the plug with a drift to compress the crush washer.  The way to do it is get a drift with about a 1/4 inch face, then smack it at 12 o'clock and move around the 'clock face'.   I use a 6 oz. hammer.  Go around a few times.  This compresses the crush washer additionally.  Then  try the oversized bits, etc.  This technique has the added benefit of closing up the stripped hole slightly for a tighter grip on the bit.

[Bill97]

The Fab; That sounds like a good one to try and easier than finding the lefthanded  twist drills I saw once.  I figured this was a common occurrence when the replacement plug was shown as 'Current' - Hex head instead of hex socket !  Will try this tomorrow

[Oldrider51]

Bill97, 

 

Don't know if your buke is the same as a 95 R1100GS, but here is an article I found on a different BMW website that might apply to yours, https://ibmwr.org/index.php/2006/06/17/extracting-a-stuck-drain-plug/. You may have to register with ibmwr.org before you can see the article. 

[Bill97]

That is an amazing technique / tutorial .... thank you !  I'm hoping mine isn't that stuck but it gives me a path forward it it is.  My biggest problem is the shroud around it that serves to drain the oil to the side plate.

[dirtrider]

Just now, Bill97 said:

That is an amazing technique / tutorial .... thank you !  I'm hoping mine isn't that stuck but it gives me a path forward it it is.  My biggest problem is the shroud around it that serves to drain the oil to the side plate.

 

Evening Bill97

 

Just be careful in how hard that you beat on any tool or technique as that BMW transmission case is a fairly thin alloy casting, you don't want to crack your trans case.

[Bill97]

2 minutes ago, dirtrider said:

 

Evening Bill97

 

Just be careful in how hard that you beat on any tool or technique as that BMW transmission case is a fairly thin alloy casting, you don't want to crack your trans case.

Yeah that has been a concern in the back of my mind on this.  A quick check of beemer boneyard showed no replacement transmissions right now .... Always seems to be  a fine line between hard enough and 'Oh Sh**'.  I'm guessing that the case may be thinner than what is on my 88 K100 !  Most engineering advances seem to be how thin can we make it before it breaks too often.

[dirtrider]

6 minutes ago, Bill97 said:

Yeah that has been a concern in the back of my mind on this.  A quick check of beemer boneyard showed no replacement transmissions right now .... Always seems to be  a fine line between hard enough and 'Oh Sh**'.  I'm guessing that the case may be thinner than what is on my 88 K100 !  Most engineering advances seem to be how thin can we make it before it breaks too often.

 

Evening Bill97

 

Those trans cases are just thick enough to not break under normal usage but the thin alloy  case is one of the reasons that you can hear all the gear noise & clacking while shifting.

 

Just don't beat on it too hard & you will be OK.    

[Bill97]

Success !  I went at the problem with my collection of hex and Torx bits to find that the washdown after my James Bay ride had flushed out the socket to take a T40 Torx bit perfectly !  Loosened it a bit , retorqued and took a short ride to warm up the gear oil.  Drain and refilled with Castrols' finest and breathed easier.  Fitted the new model drain plug so  as not to have this problem again.  Thanks to all for advice and encouragement ! 

 

The colour and viscosity of the old oil suggests it was more than due. Magnet cavity was full.

 

The original plug looks like a M6 hex but is really a Torx