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booyakasha07 booyakasha07 is offline
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Car: E93 335is
Default 335is DCT Hard shifts - 07-11-2018, 05:10 PM

Hey all --

Just had side gasket and pan / gasket replace on my DCT
Shop filled with 5L of fluid which seems normal.

Normal driving is fine, but under heavy load / hard acceleration about 1/2 the time on shifts I am getting nasty bangs when it shifts -- not as smooth as it was before.

Turned off DSC as well to see if it was a traction control issue its still doing it.
Also tried the magic reset with gas pedal or whatever and reset adaptations still issues.

I cant visibly see a leak like before -- Is it most likely my tranny fluid low? Why would it be banging hard on shifts?

The car has only 30k miles on clock of some spirited driving.

No codes.

Thanks for your help!
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Aus335iguy Aus335iguy is offline
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Car: 2009 335i dct msport
Default 07-12-2018, 03:12 AM

5l is nearly half the amount of fluid it actually needs. Dont drive it unless you top up the fluid.
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AWSAWS AWSAWS is offline
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Join Date: Aug 2014
Car: 335i MSport DCT
Default 07-12-2018, 04:26 AM


what Aus335iguy said is very possible. The harshness could be a lack of lubricating tranny fluid but there are other possibilities.

First off when they do a fluid change, they may have run through the resetting of the learned parameters on the tranny. So possible it's relearning and could be rough for some time. There are various posts on how you are supposed to drive it for about 500 miles after a reset. I don't have a link I'm afraid but google should help.

When I had my oil pan replaced they only needed about 6 of the 9L it takes. I think it's 9, I'm just going off what I recall. Anyway, thats because some of the fluid is in the lines to and from the cooler and in the little cooler itself. So it's quite possible they topped up 5L because they lost 5L but its best to give them a call to check.

If the procedure is not done right then the tranny can look full when it's not.
The engine has to be running as the pumps will activate pump fluid through the cooler lines and around the transmission. If the engine is not on then all the fluid gathers in the pan where the fill screw is. When this screw is open with the engine off, the level will be much higher than if the pump is running and it'll overflow.

The only way of knowing the tranny is full is to keep adding fluid until the fill hole overflows but as I say, this must be when the engine ( and therefore pump) is on, flowing fluid to all the components. It also has to be done before the fluid reaches a temp of about 40C because the fluid will expand due to heating.

The first big sign you'll get that you don't have enough fluid, would be an overheat warning as the tranny can't keep itself cool due to the lack of fluid.

UK FBO 335i, GCs, JB4, PI meth, BMS CP, OCC, Braided brake lines. Diff Lockdown. TMAP sensor, custom bucketless stage2

11.79@119mph on stockers, CP meth (UK, Santa Pod)
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Aus335iguy Aus335iguy is offline
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Default 07-12-2018, 06:17 AM

The link I posted has the full procedure as well any others you need
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