Now that I am driving the car after sorted issues now fixed I am noticing that the trans is shifting funny into 2nd at times. Not a ton by any means but time to time.
Seems to be better (does not do it) when the car is running at running temps.
Sometimes when it's going into second, right when it starts to go into that gear it will get a slight, like half (less than that) a second rev up (rpm's) before it goes into 2nd. Other times when going into second it will go in rather hard, a hard shift instead of a more seamless gear change. In most cases this only happens when I am just easing into the acceleration of the car. Seems if I am on it a bit harder it never does it.
Having said all this, it is not a every shift into 2nd occurrence, the shift into 2nd prob is fine 95% of the time. All other gear changes under any condition are fine.
Any reason to be concerned?

 

I know you hate my long posts, so I will try to be concise. Most of our 6HP26 trannys exhibit this very problem - in addition to other heinous annoyances. (surge-surge-surge-surge)
There are many threads about them. Most are inconclusive. You can change the fluid, have the control unit re-flashed at ridiculous costs at the dealer, try a process of getting the tranny to "re-learn how to shift" and cuss at it, (I have done all) but NOTHING has cured my symptoms - part of which are the same as yours. I periodically peruse the inter-webs for additional information on the 6HP26, but have found nothing. I am sorry for sounding sore - that's because I AM SORE over this horrible excuse for a transmission. One consolation: my car has exhibited the same problems as yours for 28,000 miles and it's still getting me down the road. Once they have warmed up, they seem to work pretty well.

My relationship with the most beautiful and capable GT machine I have ever owned is one of LOVE/HATE!

BTW your J-Gate controller will die soon also - but that is a fairly easy fix and the part is not crazy expensive.

 

I don't use the J-gate anyway. Like I said the trans at 95k shifts fine 95 if not 98% of the time. Just this small odd part of it all. Par for the course with this car I guess.

 

Sounds like we are on the same track with our car's maladies brgjag! I wonder if our two cars were consecutive serial numbers? Hah!

Mine just turned over 102K miles. I will say that, unfortunately, I have noticed the 1st to 2nd "lurch" more often in the last 2-3K miles than I was experiencing at 95K miles.... Not good news, but it still gets much less prevalent and the transmission behaves nicely after the car has about 10 minutes of running under its belt.

If you find a cure, man, PLEASE write us all about it!

 

Do you ever have a shudder / rumble strip kind of noise? Or surging / RPM oscillations at light throttle and constant speed?

There is a known problem with the early 6HP26 torque converters where a seal gives up and the clutch doesn't lock properly. It was fixed by a design change that ZF made and the newer transmissions (04+ I think) have a fix already applied.

My car has had this problem for 20k miles without it seeming to get worse. It does get worse the colder the transmission is, but always behaves fine once up to operating temperature.

I also had some shift quality problems, namely the splat into 1st when rolling up to a stop. I reflashed and re-educated the transmission and it is a lot better.

One thing that was interesting was that it shifted like sh*t right after I reset the adaptations, doing exactly the kind of thing you describe, engaging clutches too slow or grabbing too fast. Once I went through the full adaptation drive cycle, it has been fine but you need the dealer scan tool (or a clone) to do it.

I expect that some day the TC will give up completely, so I picked up an extra transmission when I ran across one for a good deal. I figure I'll have the TC rebuilt, go through the valve body and drop in a set of the superduty clutches and steels that the crazy ford guys use. Never torn apart a transmission before so I figure I might learn something and come out of it with a box that will last longer than I will.

 

I don't have the shudder issues. Just the odd shifts here and there when cold. I just take it easy till it warms up.

 

FWIW, all the same issues on mine as well, with just a little over 100k miles. And I did have the fluid and filter replaced at 65k, and a reflash at the same time, which helped the constant harsh 1-2 up shift, but that's all.

 

well for now I am seeing it as lucky since I am FAR from any constant issues we speak of here. at this point they are one off's here and there. We don't drive the car everyday either.

 

I agree with all the replies here, seems like this was the first year of use for the 6HP26 in a jag. I have one and, mine is not perfect either... 1~2 shift has always been fine though. Mine has issues when down shifting during a passing maneuver. I have been told these trannies are prone to "line pressure drops" , also the input and output speed sensors are prone to getting debris on them which may be your issue. There is a "block seal" and four sealing sleeves that seal the fluid pressure to and from the valve body/ trans assy. which are prone to leakage. I have purchased these and plan to replace them with a trans service in the spring as weather improves... I'll keep you posted, It does not sound like that difficult of a job and, the parts were very reasonable. FWIW, I've read on a few BMW forums, that they recommend replacement of these parts every 60,000 miles or so... BMW has used this trans in a few of their cars.

 

I do not have leaks on mine, floor is dry under it, and if i recall the trans is dry.

 

I'm sorry brgjag, I failed to explain well... the leaks I spoke of are internal, not external. The parts I mentioned seal the fluid pressures between the mechtronic unit/valve body and the clutch packs. One must drain all the trans fluid, remove the trans pan, remove the mechtronic unit to replace the seals I spoke about. One other thing I forgot to mention; I've read that the control unit reads data from the MAF sensor, any air leaks between the throttle body and MAF sensor can cause some wonky shifting... my '03 had that issue when I bought her. You should be able to check this easy.