Auto Tranny Sluggish

shatter2 · 02-12-2015, 06:00 PM

I have an '08 335i with the automatic transmission and it has been getting sluggish over the last 6 months. It has slowly gotten worse over time until I finally broke down and did an automatic transmission service (new pan/filter, new fluid, new fill plug). I did not drain the torque converter but was able to replace about 4L of the fluid.

At first I thought the new fluid helped (Redline AT4) but I was wrong. It is especially bad early in the morning in the first 2 minutes of driving the car. It will not downshift to 2nd gear for stop signs sometimes, which causes the engine to kind of lurch and buck. Also, until it fully warms up the operating temperature it will sometimes lazily upshift, which also lurches the car after it finally engages the new gear.

I don't know what the problem is. Any suggestions would be helpful.

CHECKERED · 02-12-2015, 06:07 PM

Quote:

Originally Posted by shatter2

I don't know what the problem is. Any suggestions would be helpful.

Auto trans are so complex these days that chasing a problem out of 1271 components will be pointless
cheap low mileage auto trans are readily available, just swap to a different one

http://www.car-part.com/

ksalih · 02-13-2015, 08:36 AM

Before you get up and buy a replacement 6AT, try resetting the adaptations with a BT tool. I had similar issues, and resetting the adaptations resolved them.

shatter2 · 02-13-2015, 09:51 AM

Quote:

Originally Posted by ksalih

Before you get up and buy a replacement 6AT, try resetting the adaptations with a BT tool. I had similar issues, and resetting the adaptations resolved them.

Is that something that is possible with the JB4 or would I have to have the actual Bavarian Technic tool?

CHECKERED · 02-13-2015, 10:27 AM

Quote:

Originally Posted by shatter2

Is that something that is possible with the JB4 or would I have to have the actual Bavarian Technic tool?

Need the BT tool, it’s under $200 and you can do back end flashes if you have a JB4,
But what you are describing sounds like a mechanical fault not a software issue.
Doesn’t hurt to try

PR3CI5N · 02-13-2015, 10:37 AM

Do you have the Alpina TCU flash?

shatter2 · 02-13-2015, 03:16 PM

Thanks for the feedback guys. I will look around to see if there is someone locally that I could borrow a BT tool from.

I don't have the Alpina flash but I want to get it done. I'll look into that as well. Thanks!

02-12-2015, 06:00 PM	#1
shatter2 New Member 0 Rep 27 Posts Drives: 2008 BMW 335i AT Join Date: Dec 2013 Location: Justin, TX iTrader: (0)	Auto Tranny Sluggish I have an '08 335i with the automatic transmission and it has been getting sluggish over the last 6 months. It has slowly gotten worse over time until I finally broke down and did an automatic transmission service (new pan/filter, new fluid, new fill plug). I did not drain the torque converter but was able to replace about 4L of the fluid. At first I thought the new fluid helped (Redline AT4) but I was wrong. It is especially bad early in the morning in the first 2 minutes of driving the car. It will not downshift to 2nd gear for stop signs sometimes, which causes the engine to kind of lurch and buck. Also, until it fully warms up the operating temperature it will sometimes lazily upshift, which also lurches the car after it finally engages the new gear. I don't know what the problem is. Any suggestions would be helpful.
	Appreciate 0 Tweet Quote

02-13-2015, 08:36 AM	#3
ksalih Lieutenant 71 Rep 510 Posts Drives: 2018 M2 LCI Join Date: Mar 2012 Location: Gilbert, AZ iTrader: (1)	Before you get up and buy a replacement 6AT, try resetting the adaptations with a BT tool. I had similar issues, and resetting the adaptations resolved them. __________________ '2018 F87 M2 LCI \| LBB \| GC Camber Plates \| Ohlins R&T 90/190N/mm \| 18x10 et33 square 275/35 \| MPe \| Poly Transmission Mounts \| Recaro Sportster CS
	Appreciate 0 Quote

02-13-2015, 10:37 AM	#6
PR3CI5N need4speed 510 Rep 1,903 Posts Drives: 2010 E90 M 335i Join Date: Jun 2010 Location: West Coast iTrader: (24)	Do you have the Alpina TCU flash? __________________ N54
	Appreciate 0 Quote

02-13-2015, 03:16 PM	#7
shatter2 New Member 0 Rep 27 Posts Drives: 2008 BMW 335i AT Join Date: Dec 2013 Location: Justin, TX iTrader: (0)	Thanks for the feedback guys. I will look around to see if there is someone locally that I could borrow a BT tool from. I don't have the Alpina flash but I want to get it done. I'll look into that as well. Thanks!
	Appreciate 0 Quote