[erikg757]

I recently bought a 2009 335i. One owner and maintained at a dealership since 2009, this thing is a dream. Never beat on. Xhp stage 2 and stock power.

I was surprised to find that the transmission will flare on the 4-5 upshift and occasionally 3-4. Got a couple faults.

This weekend I swapped out the valve body for a used one with no issues, new solenoids, new seals/sleeves, new pan.

After the service, it is still slipping between 4-5, but it feels like its actually trying to go into gear when before it was behaving like the car was in neutral.

It’s also getting confused about what gear it’s in. It got stuck in 5th. Downshifted to 2nd and my dash said M2, but it was still in 5th. 1-3 shifts feel great. Really confused what is going on here because the car was never beat on and I can’t imagine the clutches are burnt.

It has also clunked a few times going into drive. Never did that before the swap.

I have a second 6AT in my basement but I really don’t want to go through the trouble of swapping a trans until I’ve tried everything.

[whyzee125]

How many miles on the car? Was the fluid factory fill? Those adaptation values are really high--I'd probably have tried a zip kit in the original valve body before taking a gamble on a used one but something internal is worn. Did you use lifeguard 6?

[erikg757]

Originally Posted by whyzee125

How many miles on the car? Was the fluid factory fill? Those adaptation values are really high—I'd probably have tried a zip kit in the original valve body before taking a gamble on a used one but something internal is worn. Did you use lifeguard 6?

120k miles. Factory fill. The adaptation values are high on ABC clutches which is what I don’t understand, because all the other gears work fine. I used LiquiMoly Top Tec.

[konstat]

Originally Posted by erikg757

120k miles. Factory fill. The adaptation values are high on ABC clutches which is what I don’t understand, because all the other gears work fine. I used LiquiMoly Top Tec.

Is the used valve body rebuilt? If not you’d definitely want to put a rebuilt one in by a reputable shop like Eriksson Industries in CT. I put in a rebuilt valve body from them a month ago and it cured my 2 and 5th shifting issues.

I will say that xHP causes adaption values to be higher than normal since it requests more out of the solenoids. Normally not a bad thing per se but since you have shift flares that seems like a clutch issue to me.

Also make sure your fluid level is correct by checking it at fill plug per the ZF procedure. A jolt when shifting into drive is a symptom of low fluid, it happened to me after changing fluid until I double checked the level and topped it off then it went away.

For what it’s worth I’ve read in other forums that liqui moly performs really poorly in the 6HP but I haven’t confirmed that myself. You might want to change fluids to Hotshots adrenaline SS and throw some lubegard ATF protectant in. If it is a clutch issue those 2 fluids are highly friction modified and will be your best chance at not swapping transmissions. I’m running those 2 fluids and the transmission is really liking it.

I changed my factory fill at 132k miles and luckily didn’t have any issues, however if there were a lot of clutch particles in your fluid then changing the fluid could’ve caused clutch slip.

[erikg757]

Originally Posted by konstat

Is the used valve body rebuilt? If not you’d definitely want to put a rebuilt one in by a reputable shop like Eriksson Industries in CT. I put in a rebuilt valve body from them a month ago and it cured my 2 and 5th shifting issues.

I will say that xHP causes adaption values to be higher than normal since it requests more out of the solenoids. Normally not a bad thing per se but since you have shift flares that seems like a clutch issue to me.

Also make sure your fluid level is correct by checking it at fill plug per the ZF procedure. For what it’s worth I’ve read in other forums that liqui moly performs really poorly in the 6HP but I haven’t confirmed that myself. You might want to change fluids to Hotshots adrenaline SS and throw some lubegard ATF protectant in. If it is a clutch issue those 2 fluids are highly friction modified and will be your best chance at not swapping transmissions. I’m running those 2 fluids and the transmission is liking it

I think that is what I am going to do. Was trying to avoid swapping the transmission, but I’m pretty sure the flaring is a clutch issue.

Going to have the valve body rebuilt and still on the fence on if I want to drop in fresh clutches and bushings while the trans is out of the car.

Thanks for your insight on fluids, I’ll look into friction additives!! I’m pretty determined to have a stong ZF6. Will keep this thread updated

[konstat]

Sounds good man curious to see how it turns out. Hope you get some good results out of those fluids.

Also note that the Hotshots Adrenaline SS is used as the transmission fill fluid while the lubegard is the additive.

As far as transmission rebuild would you use a shop near you?