Thanks for your reply, transman. It’s kinda hard to know where to start with this since there are no codes. I’m not sure about the 90 MPH though, the car feels, if anything, faster and more powerful than before.
I think I shouldn’t have said 4th when I wrote the OP…it’s really any gear. I could floor it from a standstill and it won’t shift at the redline if I stay on the floor. Do you still think it’s a driveability issue? If so, what should they be looking at? Also, what part of the car stops the engine from going past the redline? Is it a component on the engine (ECM, or a sensor) or is it something in the trans?
Other than this shifting issue, it shifts fine, drives fine, lots of power, no rough starts or idling/running…everything else is like before.
Addendum: I ran across this thread on the web, could my problem be something like this:
http://lt1tech.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=7;t=000426
As several have stated/alluded, most vehicles are unable to sustain maximum speed in OD. Direct drive, 3d gear in most 4 speed overdrive transmission, will usually provide the maximum speed available, and if shifted into OD at WOT, an immediate downshift usually occurs as the engine is unable to sustain the speed at lower RPMs/reduced power output. Reduced compression due to normal engine wear could result in reduced MAP values which may result in the ECU not allowing the up-shift…
It sounds like many people who followed these directions had success:
http://shbox.com/trans/A4_trans_linkage.html
I must be really explaining this incorrectly.
This is what’s happening: In any gear, with the pedal to the floor and staying on the floor, the car will go into “passing gear” and accelerate quickly towards the redline, but instead of shifting at the redline like before, it will now just continue past the redline into the red. Every other kind of driving/shifting is normal. It’s just when the pedal is kept to the floor (in ANY gear) that it doesn’t realise that it’s at the redline and should shift.
Does that explain it any better? Sorry if my terminology is incorrect.
I understand what you are saying and yes, it could still be a drivability issue. TPS for example. Even a Pressure switch or speed sensor malfunction. The shift points are controlled by PCM. A good scan will probably reveal something. I would let a trans shop take a quick look.
transman
UPDATE
Well, I think I’ve KINDA figured this out. I don’t think there’s anything wrong, anymore…but I still can’t explain the change.
I was looking at the tach today and realised it used to shift at 6250, actually, not 6500. I was reading about all the multiple levels of “engine protection” on this car and decided not to worry about the red area on the tach (or the accuracy) and to just let the computer worry about protecting the engine. So I did a full throttle run and sure enough, at 6700 or so it shifted without any drama. Did it again and same thing. So, I think it’s actually shifting at around 6500 now but I’m just seeing the needle swing past. With no codes and a proper shift (no fuel cut out, so it can’t be hitting the rev limiter at 6800), I think it’s fine. The only thing I can think of is that the ECM was reset when the engine/trans was out and is now shifting how it should…maybe before someone really babied it and it lowered the shift point for WOT? Who knows.
Also, the main bearing/half case bolts were over torqued before this work was done and now they are at the FSM specs, so maybe the engine is turning more freely? Maybe that’s a long shot.
Anyway, case closed as far as I’m concerned. I also did a trans fluid/filter change yesterday, so that’s good too. Thanks everyone for your input and help on this issue.