DCT transmission overheat?

[sometorque]

Originally Posted by WhatsADSM

Why are you attacking him like this?

The OP has been very straight forward about everything, and quite frankly I believe the DCT (at least the clutches themselves) are fine. There is A LOT of data on these transmissions which shows they are actually pretty strong, and I don't believe for one second that an owner taking the car to redline (7000 rpm on a transmission that is RATED for 9000 RPM) a few times and doing some burnouts (where the clutch is 100% engaged) is going to really stress it that much. I would track my E90 M3 which included 20+ minutes of going to its 8000+ redline and shifting HARD (full throttle, flying around turns, on take of Pirelli slicks). It took everything is stride, not a single issue... and that is certainly the majority of the people's experience.

The reality is while the transmission is mechanically very stout, it is electro-mechanically very complex. So it seems pretty obvious to me here, that based on the conditions when the OPs car would throw the light, the duration of the light, cadence of incidents, and the way it behaves under all other conditions, that we are looking at a bad sensor (or poor wiring/grounding) causing the TCU to see an elevated temperature when no such thing actually existed. Unfortunately beyond looking for a wiring/grounding issue, it sounds like the various temp sensors in the DCT are non-serviceable and therefore it would likely end up needing an entire assembly anyways So I definitely wouldn't say this is a true DCT mechanical failure, I wouldn't say any of this was due to abuse, and most of all I certainly wouldn't attempt to burn the OP at the stake because of what he has posted here. He has done nothing wrong.

OP:
Best of luck to you, sorry you got bit by a bit of a weird DCT problem. In general the Getrag DCTs are very good transmissions, but like any complex electro-mechanical part they aren't perfect. Thanks for sharing your experience.

Thanks. I wanted to document it as best as I could for others in the future who may have this issue. I'm fairly convinced mine was just an anomaly, and don't have any jaded views towards the DCT or the 135i. It was a hoot to drive for the few years I had it and this was a great forum to hang around. I have a bit of car ADHD, so I suspect I'll end up buying another one in the future. In the interim, I'm going to go check out a 2009 c6 z06 tomorrow that I'm hoping to make a cash deal on. Fingers crossed!

Regarding the clown attacking me, I've seen him around these forums throwing his shit around like it don't stink. There always has to be one, I suppose.

Appreciate the kind words!

Pic of the new daily. One owner car, 5spd LSD with all the maintenance history. Nowhere near as quick as the 1er, but it's a hoot to put around in.

[sometorque]

Originally Posted by Mr Rooty Von Tooty

You are full of shit. Of course the dealer was stumped. They didn't want to waste their time on your behalf diagnosing some problem either real or imaginary. They are always happy to diagnose something that will lead to an immediate repair, "We are so sorry fool, but we believe the DCT needs to be replaced. That'll be around $10,000 (chuckling under their breath)!"

And you sold the car for a Lexus? What you did was dump the car on some poor fool suspecting an expensive repair. Few people would go from a BMW 135i to a Lexus except for financial reason.

I get really tired of guys like you always rationalizing your behavior. I have had hundreds of business dealing with characters like you. The more BS you lay down the more transparent your basic dishonesty.

I hope Santa dump a couple of tons of coal on your driveway!

[WhatsADSM]

Originally Posted by sometorque

Pic of the new daily. One owner car, 5spd LSD with all the maintenance history. Nowhere near as quick as the 1er, but it's a hoot to put around in.

I nearly bought one a few years ago to do an LS swap to and turn it into a final street/hpde car.

IS300s with a manual are extremely difficult to find, let alone in good condition with reasonable milage. Congrats on the purchase, they are very under appreciated cars! Also good luck with the C6z (we must have similar tastes). Another great track street/track car for the money just be careful, they have been known to have some valvetrain related issues.

[bung206]

Originally Posted by JDM_CL9

Sorry to revive an old thread but I think I may be having the same problem.

Did you get any Fault Codes etc when you determined it was the Speed Sensor causing the issue?

Yes, I had a RANGE of fault codes.

The issue is with this car a lot of things depend on things you wouldn't expect have anything to do with one another. For e.g. a busted speed sensor that hasn't TOTALLY failed may not throw up dash lights, but the freeze frame data and fault will be recorded. Also, a busted wheel speed sensor will also cause airbag faults (because the airbag ECU needs to know what the wheels are doing before deciding to deploy the airbag or not). You really need expert assistance (or at the very least good problem solving abilities) to diagnose this. I am convinced that if I'd taken this to an independent or official BMW dealer I'd be out THOUSANDS of dollars in diagnostic fees. Such is the nature of these black-box style electronic assists.

Either that or its badly designed junk, I mean how can a failing ABS sensor cause gearbox overheat and potentially damage? Maybe there was a very good reasons the engineers it this way?

Anyway, attached is the list of fault codes as read by ISTA on the evening of the gearbox overheat message. Additionally, when I looked at the freeze frame data it showed the gearbox was in 11th gear (which is obvously not possible).

In my situation the only recurring theme was a string of busted ABS sensors. At this point I'd replaced the front left and front right, now the rear right was playing up (see screenshot), so I spent $30 for an ATE branded OEM replacement from Pelican Parts (then another $30 for USPS Intl express) and three days later the car was fixed.

I've done another 1500 or so miles since then some of which was spirited driving, burnou.. er brisk accelerations and the car has been just fine.

[sometorque]

Originally Posted by WhatsADSM

I nearly bought one a few years ago to do an LS swap to and turn it into a final street/hpde car.

IS300s with a manual are extremely difficult to find, let alone in good condition with reasonable milage. Congrats on the purchase, they are very under appreciated cars! Also good luck with the C6z (we must have similar tastes). Another great track street/track car for the money just be careful, they have been known to have some valvetrain related issues.

Thanks! I'm really happy with it. It's nowhere near as quick as the 135i was, but it's a hoot to put around in while on the daily grind. I picked it up with 107k miles and I'm up to about 112k. These things are reliable as gravity so I'm hoping to hang onto it for a good while. Nothing extensive in the mod column planned for it, but who knows what will happen a year or two from now lol

As for the c6z, unfortunately the deal fell through. I'm reasonably aware of the valvetrain issues with them since a buddy of mine owns one and is an encyclopedia for all things LSx. He's been giving me a hand with the hunt as well, so I'm optimistic the right one will come along soon enough.

[WDE82]

Originally Posted by Mr Rooty Von Tooty

You are full of shit. Of course the dealer was stumped. They didn't want to waste their time on your behalf diagnosing some problem either real or imaginary. They are always happy to diagnose something that will lead to an immediate repair, "We are so sorry fool, but we believe the DCT needs to be replaced. That'll be around $10,000 (chuckling under their breath)!"

And you sold the car for a Lexus? What you did was dump the car on some poor fool suspecting an expensive repair. Few people would go from a BMW 135i to a Lexus except for financial reason.

I get really tired of guys like you always rationalizing your behavior. I have had hundreds of business dealing with characters like you. The more BS you lay down the more transparent your basic dishonesty.

I hope Santa dump a couple of tons of coal on your driveway!

You're a douche. What are you even talking about? Get out of here.

[Mr Rooty Von Tooty]

Originally Posted by WDE82

You're a douche. What are you even talking about? Get out of here.

It is way beyond your feeble ability to think dick!

[WDE82]

Originally Posted by Mr Rooty Von Tooty

It is way beyond your feeble ability to think dick!

You got mad at a guy for selling his 135i and then assumed his entire life situation based on his next purchase. There's no reason to do that. You're a bitter asshole. Toxic for the car enthusiast community.

[sometorque]

Originally Posted by WDE82

You got mad at a guy for selling his 135i and then assumed his entire life situation based on his next purchase. There's no reason to do that. You're a bitter asshole. Toxic for the car enthusiast community.

He's not worth the time. Don't feed the trolls.

[dtla1]

So, I'm getting this exact issue now. Funny enough, I didn't even remember posting on this thread years ago, and now I'm having the same issue.

I'm going the way of one of the previous posters which mentioned a wheel speed sensor. I actually pulled the codes off my car and one of them mentioned rear left wheel speed sensor. The sensor itself should be here today and I'll install today and update if the issue comes back or goes away.

If it does come back, next step will be battery replacement. About a month or two ago I was having an issue where the car randomly died (dead-dead) with no lights, no power to anything etc. That issue hasn't come back since, but it could be causing weird issues like this one.

At any rate, I plan to come back here to document what I find so that info can be had for the masses.

[Happy Jose]

A couple of comment about this thread. You can't see the oil leaks from either the engine or transmission without removing the covers. My DCT was leaking, but I never saw any oil on the garage floor. Luckily for me, the dealer spotted it shortly before the mfg warranty expired.

With this car, you really need a scanner specific to the car like the Icarsoft BMM V2.0. There are all sorts of codes specific BMWs you won't be aware of without this scanner. Also you'll have historical & pending codes that can reveal problems.

I haven't gotten any codes with the DCT, yet. Knowing a replacement is $10K, I treat it with a great deal of respect. I also don't use the Sport Mode or Paddles. The Sport mode seems a bit flakey the few times I tried it.

One other thing about DCT is they work quite differently that normal automatic transmissions with torque converters. To move slowly forward in heavy traffic, the DCT slips the clutches which accelerates their wear.

I like the DCT, but I won't opt for it on my next car. I'll buy my M2 Competition with the 6-speed manual!

[dtla1]

Yeah I know you have to look at the pan directly by removing the covers in order to see any leaks. I saw oil down there, but figured it was from my slow leak coming from the Engine Oil Pan gasket failing. Might just schedule a replacement to be safe. The light did end up coming back up after replacing the wheel speed sensor that threw a code so I'm ruling that out.

For the past week I installed the wheel speed sensor, I drove the crap out of the car on some fun roads for about 300 miles with no light on. But I also have had the light come on twice as I'm getting home, which does start to sound like low fluid, or clutch wear or something like that. I'll be replacing the battery this weekend to rule that out since I think we all know that bad batteries cause the weirdest of issues.

If that doesn't solve it then DCT pan, gasket, filter, fluid replacement for sure. May try to start talking to people about clutch replacement. I don't know that I've ever actually read anything about the clutches actually failing though so I think more research is needed regardless.

[Happy Jose]

Originally Posted by dtla1

Yeah I know you have to look at the pan directly by removing the covers in order to see any leaks. I saw oil down there, but figured it was from my slow leak coming from the Engine Oil Pan gasket failing. Might just schedule a replacement to be safe. The light did end up coming back up after replacing the wheel speed sensor that threw a code so I'm ruling that out.

For the past week I installed the wheel speed sensor, I drove the crap out of the car on some fun roads for about 300 miles with no light on. But I also have had the light come on twice as I'm getting home, which does start to sound like low fluid, or clutch wear or something like that. I'll be replacing the battery this weekend to rule that out since I think we all know that bad batteries cause the weirdest of issues.

If that doesn't solve it then DCT pan, gasket, filter, fluid replacement for sure. May try to start talking to people about clutch replacement. I don't know that I've ever actually read anything about the clutches actually failing though so I think more research is needed regardless.

My DCT had to be pulled to replace the side gasket & mechatronic sleeve. It took 9 hours of labor, and BMW got the bill.

BMW doesn't repair this unit. It replaces it with a new unit supposedly $10K! I believe owners have dumped the car when they suspect trouble with it. This would be a hard bill for most people to swallow no matter how much they like the car.

In any case, my next car will be a regular auto or 6-speed.

[dtla1]

I've had that gasket and Mechatronics sleeve or whatever it is replaced by BMW under CPO about 3 years ago now.

[Happy Jose]

Originally Posted by dtla1

I've had that gasket and Mechatronics sleeve or whatever it is replaced by BMW under CPO about 3 years ago now.

As far as I know, there isn't any service entity that'll replace the clutches. If they fail, you have to replace the whole unit. My advice would be to treat the DCT with a great deal of respect.

I have an extended warranty, so I'm pulling off the covers and check the pan gasket and the DCT for leaks. BTW, replacing the pan gasket is an expensive repair, since it involves removing the subframe.