First gears are not happy
 

Hello there

Since i have the car i have that infamous jerk from 2 to 1 when coming slowly to a stop (red light or stop). Putting in S mode make it downshift earlier and almost remove the jerk.

Now i changed the rear tires couple of weeks ago.
I know, should change all the 4, but it was urgent before travel as the rear ones were shot and front ones still have around half thread - the difference probably comes from my old steering angle sensor issue which disabled the 4x4.

Since that (i don't think it was present before or very light) i have some weird feel on low gears (1 and 2) on very slow speed and low rpms, between 800 and 1500rpm.

It feels like micro gas cutout, or small jerks.
When putting more gas, no issue and the gears pass fine.
When driving at the same 800/1500rpm range in higher gears, no issue.
Seems to not happen when the car is cold.


Where could that come from, and how to get rid of? Do i really need to change the front tires as well? As it's a 2005 facelift model i understood that the 4x4 system is more permissive than the pre-facelift.

Yeah.....

That's the seals in the transmission valve body (2-1 slamshift) it's not very difficult with a lift and the rebuild kit isn't very expensive (except for here...)

Some of the guys changed filters and oil plus reset adaptations, although this is one of those discussions like reusing stiffening plate bolts [emoji374]

Sent from my SM-A528B using Tapatalk

Sounds like leaky seals in the valve body. People do valve seal repair, solenoid replacement or full mechatronics replacement to fix this issue.

I think you can monitor the valve body pressures with the likes of foxwell scanner and compare to known proper operation.

I suppose this seals replacement involves opening the gearbox, so changing the oil?
The car is around 300k old, as I've read here and there a simple oil change won't be enough as it can unstick some old gunk and clog / kill the gearbox.


And btw in case of misunderstanding, it's not about the jerking from 2 to 1 to which i'm already used and living with, but about the bumps / shakes on low rpm on 1 and 2 which is new and more annoying.

Yes to changing the oil/filters along with the seals and solenoids. The fluids are NOT lifetime no matter what people say and there is no reason that new "clean" fluid will unstick gunk and you will have new filters to catch any crud your old plugged filters weren't getting before. The question comes down to whether you reset the adaptations or not after the fluid change and that's where people say the risk is for the most part.

I still believe your valve body is the culprit for both issues. The only other thing that may cause shaking is a torque converter that is dying, but it wouldn't be causing the 2-1 slamshift.

Sent from my SM-A528B using Tapatalk

So you say i should be able to do such complicated operation on my parking lot? I saw a lot of topics about this gearbox and I'm not really optimistic about that tbh.

What about the reset operation which never changed anything for me but maybe i was doing it wrong? Key on 2, gas to kickdown for about 40sec, lift gas start car, drive.

It's possible on ramps and to be fair, with instructions it's pretty much take old part out stick the part that looks the same in its place.

The reset you list is completely fake, the only way is with a bidirectional scanner like the Foxwell nt-510, nt-520 (not all models) or ista-d, etc.

I personally recommend the Foxwell since it is tough, easy to use and can stay in your car no matter the season.
50c-60c here and it has survived!

Remember that filling up the transmission is at temp, going through each gear and through the bottom of the pan!!

Use www.realoem.com and put your VIN into the system and it will show every part, bolt, etc allowing you to find the correct parts from more that just the dealership....

Sent from my SM-A528B using Tapatalk

Yeah that sound a thing that i will wipe under the carpet and deal with if it doesn't worsen with time.


I have ISTA, and i've seen the Reset adaptation values operation but did not really wanted to tamper with.
Should i try the reset, or it could make it even worse?

It gave me those values but i have no clue if they are ok or not..

Clutch fill pressures:
Clutch A: 78.0
Clutch B: 184.0
Clutch C: 265.0
Clutch D: 170.0
Clutch E: 750.0
Rapid fill times:
Clutch A: 47.0
Clutch B: 23.0
Clutch C: 48.0
Clutch D: 0.0
Clutch E: 0.0

04 N62 4.4 here, 44k original miles.

I recently replaced the solenoids, the four sleeves, the AT adapter plug, the mechatronics sealing sleeve, along with the usual items for a flush, the fluid, the gasket filter, the magnets, the fill and drain plugs.

This is the second time, the first was in 2019 when the o-rings on mechatronics sealing sleeve flattened and were leaking. I didn't drop the valve body that time. No reset then and no problems until recently starting on uphill and having problems engaging one of the early gears. The four sleeves were worn and the adapter plug was deformed. One of the solenoids wasn't sealed properly against the valve body.

After driving without resetting the adaptions and experiencing some rough shifts, I decided to reset them with my Foxwell 520 Pro. Now, I'm driving cautiously, not generally exceeding 2k rpm during the relearning process. I didn't see a way I could do the official procedure outlined in relearning without a closed track. The shifts are much better than before.

I am by no means an expert transmission guy but, I'd guess you are leaking between the D and E channels in the valve body leading to that high reading and 0 refill time (cause it's already full?) I hope RRRPhil sees this thread and chimes in because he is an actual transmission expert.

Sent from my SM-A528B using Tapatalk

My values before the reset were:

Pressure: -140, 185, -135, -92, 204
Rapid Refill: -2, 26, 19, 0, 0

I had a different problem and the values are quite different. However we both have 0, 0 for refill on D and E.

As you wrote, hopefully Rapid Refill Phil will chime in :thumbup:

I have a bit more info about that case.
Wrote to ZF and they told me that the 750 value might be a leaking E clutch.
Or a failing solenoid. Or a leaky/sticky valve.


I also found an old ISTA print from a year ago, and the values were quite similar to today so i don't think it's related to that recent continuous jerk at low speed.

But possible related to the bump from 2 to 1 which always been here.


Could it be a transfer box or read diff issue?

You can disable the TC by pulling a particular fuse. If the symptom is easy to reproduce you can test if it's coming from the TC. (if your truck is new enough to have x-drive.)

Google for which fuse. When you pull it your wipers may run continuously like the E90 I was working on. You can maybe also pull the wiper fuse.

You can measure your exact rolling circumference: put a dab of something on the front and rear tire such as grease or peanut butter and drive fwd. Find the marks and measure to the nearest 16th inch.

BMW spec is tires within 3% of original size and 1% between axles.

87.6" is the expected rolling circumference most E53 tires.

87.6/100=7/8" must be less than 7/8" difference and actually I just saw that bmw says 2mm max tread depth difference which prob works out to even less.

2225/π= 708.26 mm

704.26*3.1415=2212.433

2212/2225=0.994 that's only 6/10 of 1% difference.

There are regular threads about jerky performance and even TC self destruct from a single tire being replaced.

Low speed continuous jerk can be from CV or front drive prop. Just throwing that out.


Sent from my iPhone using Tapatalk Pro

I no longer work under my X5 in parking lots. It's a safety issue. Everything I'm doing might be safe but I can't predict when some driver might swing into the parking lot and hit my car while I am under it.

It's a private parking with a passing rate of 2 cars a day so safety wise I'm not really concerned. More about the accessibility to all the things down there

Narrowed down the issue cause. Unplugged the TC connector, jerking gone.
So i guess the tc did not liked the change of only 2 tires, even if the thread difference was bigger with the used rear ones.
I'll plan to do a tc oil change and reset (and ideally change the 2 remaining tires) meanwhile will drive in 2wd to avoid any extra wear.

Could a reset only make a difference in relearning to behave with new tires size?

Hi Grounch curious, I had reverse problem, replaced fronts and had this weird shudders behaviour, replaced all 4 tires with new ones and was ok, didn't do any resets relearing after new tires.....

First gears are not happy
 

No, you can't train the TC to be happy when different size tires are front and back axle. It's not about tread depth if the tires are different models it's rolling circumference. You can measure this by putting a dot of grease or similar on all tires and driving then measure the distance between the dots.

7.3 ft is the baseline 2225mm the car expects. 87.6" ± 1% 86.7—88.5 should be the limits.