Automatic trans shifting issue

[Juggernaught5]

Hello all:
I searched the forum and haven't seen my issue discussed. I just purchased a 2006 z4 3.0si with an automatic gearbox. Having driven manual transmission cars for the past 10+ years, I didn't pick up on my issue until after I had driven the car for a few days. Here's what's up:

In normal auto mode (D), on initial acceleration there is a brief hesitancy - like the car starts off in second gear, then shifts to first, then back to second. It's most noticeable during normal acceleration, such as from a traffic light. It's very rapid - the first two shifts occur after being in each gear for two seconds or less.

There's no hesitation in manual mode, so I don't believe its a throttle/carb issue. I have noticed that in manual mode, if I come to a stop without changing gears manually, the transmission drops to M2 once the car is no longer moving, not M1 as I would expect. There's also no hesitation if the sport button is depressed (although it seems to stay in third gear until over 4000 rpm).

I've attempted the adaptive transmission reset, but I'm not noticing anything different (or not doing the reset properly). When I try the reset, I'm not hearing the ticking/clicking noise as mentioned. I also have tried to complete the throttle reset - again, no difference or I'm not completing the reset properly.

Any thoughts? The car has only 37,000 miles, but given that the air filter element is of 2006 vintage, there may not have been regular maintenance post-warranty.

Thanks in advance for your help!

[newbizie]

Seems to me everything is fine, mine does the same thing except i have not noticed the 2-1-2 issue you described, if your in sport mode i would guess your suppose to get shifts at higher rpms

[the dink]

What type transmission do you have? Two different ones came in those cars, a GM built which will be hydramatic or ZF HP unit built by the germans. Get underneath look for a tag on transmission. Sound like solenoid or senser problem. A scanner will be needed to pin point which one.

[BMWZ42.2I]

maybe you need a new trans filter and flush? Apparently bmw reckons life time transmission oil but i think they are full of s.hit lol

[Juggernaught5]

Thanks so much for these thoughts I really appreciate everyone's willingness to help.

I took my Zed to my local garage (Bavarian Motors Ltd, Phoenix AZ) who has confirmed nothing is wrong with the transmission. The car was given a thorough inspection and pronounced in great mechanical condition with no issues. They believe the car has been driven fairly gingerly and has developed a relaxed shift pattern based on this light use.

BML reset the dynamic driving dynamics, and prescribed using the 3-litre engine to its fullest potential, as often as possible.

They also tightened up the strut braces, and replaced my air intake and cabin filters.

[TomHickory]

I have a new to me 2007 3.0 with the paddle shifter/auto

I have also noticed a Sport mode gear 2 start sequence unless I paddle it to 1 at a stop - very low but quick. I had some good counsel from a track Z4 user who suggests that if you use this Z4 tranny on the track for a DE that you keep close watch on the temps since the paddle shifter can get hot during hard (track DE ) use. Going to try it on the track this fall at new Corvette track in KY for a BMW DE. Will add better wheels and track friendly tires, with RE neg. camber plates up front to see how it does on the track. And also some track pads and high temp brake fluid. Will see how a non M Z4 does the corners with paddles. Zoom Zoom


Tom

[Juggernaught5]

Update: I found a garage within walking distance to my home, and took the car there for a second opinion on the transmission issue. They agreed there were no transmission problems, but did note a hesitation on acceleration and completed a second full inspection. They discovered that my first mechanic missed a broken axle! Once this was repaired, there has been a marked change in how/when the car shifts from first to second, and the smoothness of all shifts in general.

[Psychodo]

Originally Posted by Juggernaught5

Update: I found a garage within walking distance to my home, and took the car there for a second opinion on the transmission issue. They agreed there were no transmission problems, but did note a hesitation on acceleration and completed a second full inspection. They discovered that my first mechanic missed a broken axle! Once this was repaired, there has been a marked change in how/when the car shifts from first to second, and the smoothness of all shifts in general.

How the heck did they miss a broken axel?

[Finnegan]

My guess is target fixation on the transmission to the exclusion of up or downstream components. "The work order said transmission, I looked at the transmission."

That is the difference between a technician and a mechanic.

[KLH]

"The car was given a thorough inspection and pronounced in great mechanical condition with no issues."

That's almost scary......I suppose the axle wasn't damaged when the original inspection was performed?

[Juggernaught5]

When the new tech told me it was the axle, I immediately wondered how I could have driven the car. Paraphrasing the tech, they had to take apart/remove something to see that the axle was separating - it wasn't snapped. The new shop used a BMW checklist to go over the car - I believe the other shop only inspected the transmission issue and implied road worthiness when I asked if they found anything else concerning.