After Trans oil Change/harsh downshift now

[Rockit]

Originally Posted by Overboost

From my reading and research, I read that procedure you listed and some described hearing the clutches reset, others on our forum here said it did nothing, no sound or no difference. BMW Logic7 seems to be the reference for your ZF box and they claim the throttle pedal--> transmission adaptations reset procedure is only an old wives tale.

Everything about your ZF 6HP26, 6HP19, 6HP28 transmission issues | BMW LOGIC7

I did find this video for the ZF gearbox and a chart listing the adaptations reset procedure but honestly, I am no expert and am hoping to learn more from this thread.

https://www.youtube.com/watch?v=nN78ukXXF_o

Thanks, really appreciate the help. I saw those too....will report back with the trans program, if it workers or helps. I have to head out for the afternoon.

[andrewwynn]

Originally Posted by Rockit

Can you get a little more detailed please. The TCM is the same as the neutral safety switch? Does it unbolt or how to you clean it?

TCM is transmission control module in the e-box with the DME.

You are calling the transmission position switch the metal safety switch. It actually reports every gear not just park and neutral. I’ve been referring to it as the selector switch not sure where I heard that but I just looked it up on real oem. BMW calls it the transmission position switch.

Anyhow less than a week ago somebody on xo couldn’t start their x5 because the connector to their position switch was loose (the locking collar didn’t lock).

Since the TCM needs feedback of which gear is selected to determine how to control the transmission, all hell breaks loose when it reports strangeness like it’s in gear 54 which mind did once.



Note there is a connector after about 8” of wire that’s the position switch connector I don’t know if that goes directly toward the TCM or plugs into the transmission and piggy backs into the main transmission connector.

I have the 3.0 and it uses an internal position switch so I only have one connector.

[upallnight]

He has the ZF trans not the GM trans. Two completely different trans. Usually slamming into gears can be associated with pressure from the valve body. Could be time for a valve body rebuild. Google valve body for the ZF trans and sticking valve.

[crystalworks]

Originally Posted by Overboost

This is always my fear when considering a transmission fluid/filter change. Some have no issues and some have issues after the change. From reading and researching, I can not get a clear understanding on the adaptation resets for a simple oil and filter change.

I would love to hear more theories on what should actually be done when changing the oil/filter in both ZF and GM automatic gearboxes and also the recurring conversations of leaving high mileage transmission alone vs. diving in and rolling the dice.

One guy I would love to hear from the is automatic gearbox guru over in the UK (I always forget his name) but he knows his stuff. (RRPhil)?

I am currently doing our ZF 6hp19 in the e61 wagon. It has 186000+. Just barely starting to rough down shift under certain conditions. I already drained the fluid out so I am committed. I am doing the mechatronic seals (4 of them + bridge seal), mech sleeve, and of course new fluid. Hoping to find a cracked bridge seal or something as that will tell me for sure how much success I am going to have with the whole endeavor. Trying to avoid having to have the mechatronic rebuilt w/ new solenoids and internal seals. I will use the Foxwell for adaptations and resets of the trans. Will let you know how it goes OB.

After I finish with this one the wife's 6hp26 in her e70 is getting the same treatment with the addition of a rebuilt mechatronics unit. I'm hoping the complete service will avoid having to replace the E clutch bushing/bearing that goes out sometimes and causes pressure loss in higher gears. The symptom it is having is slipping out of gear and going into trans limp mode at highway speeds. Only done it 2 times 6 months apart, we parked it after the second occurrence so hopefully no trans rebuild is in our future. *fingers crossed*

[andrewwynn]

@ rockit: do you have a scanner that will show you realtime solinoid pressures? With the 4.4 it's not uncommon to develop a hard downshift from 2-1 from seal wear and usually is fixed with seal replacement from my understanding.

With the relatively not terrible prices of the solinoids, often people will choose to hear replace the solinoids with the seals. (I was planning to do that when my transmission started to slam shift before I discovered the dirty connector actually causing the problem)

[wpoll]

FWIW, the trans reset procedure mentioned about (press the gas pedal for 30 secs etc.) is complete crap.

The reason it persists on the internet is that it DOES actually do something - it forces the transmission into sport mode - and that does feel different to drive, so the owner thinks they have reset something. But once you turn off the key - game over. The trans reverts to normal mode and you have done nothing. But by then you are convince did something and you don't notice the next trip is back to the way it was...

The same sort of myths exists in motorcycling circles, for resetting ECU and throttle adaptations etc. It's all hogwash....

[Redraptor141]

When I did my 535d E61 5 series (6hp28/32) the procedure from BMW/ZF was to do the oil change as per instruction and then perform the Oil Change Adaptation reset NOT the clutch wear adaptations.

So the oil wear is as the trans oil breaks down the clutch friction material will cause the oil viscosity to increase and the trans will adapt to this slowly over time. So the trans pressures required to clamp the clutches is differnt.

Once you change that fluid to nice clean new stuff the computer still thinks that it’s the old thick stuff, and the clutch application pressure it apples will be the same. So you get hard changes. Resetting the oil adaptations values means the trans is set to a datum as “just off the line” aka new oil. I’d start with the oil adaptation reset and see how it goes.

But equally ZF 1/2 soleinoids are notorious for going and are really easy to change. I’m sure when you do you can but I’m the new “E” style soleinoids...... but you would have to research that!

Only problem with that is the sump need to come back off to get to the back of the mechatronics unit. Plus if your there you might as well get someone to open the mecatronics and give it a good clean out. Only takes a bit of grit in a fluid way to change the pressure flow and therefore effect gear change characteristics.

[Redraptor141]

Oh and plus one for the throttle pedal reset. It’s rubbish. At most you reset the TPS adaptations

[Redraptor141]

BMW should have just not put a bloody “lifetime” sticker on it and just do an oil change every 70,000 miles life ZF reccommed!

[andrewwynn]

Originally Posted by Redraptor141

Oh and plus one for the throttle pedal reset. It’s rubbish. At most you reset the TPS adaptations

Correct will not do anything to the transmission, but will recalibrate the throttle position sensors.


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