Elevating my DIY game to a new level

I've been wanting a set of Quickjacks for a long time, and I finally got one for my cars this past Christmas. The Quickjacks quite literally enable me to elevate my DIY game (or at least my cars) to a new level:

My work space setup. The laptop connects to a USB-OBD-II interface for monitoring the transmission fluid temperature for my valve body removal/reinstallation. The strategically placed jack stands pictured are a failsafe measure to prop up the car in the unlikely event the Quickjacks were to fail.

I wasted no time in putting the equipment to use, and it sure has been useful. After swapping in my car's winter wheels/tires, I tackled a transmission valve body removal/reinstallation, which I had been waiting on the Quickjacks to do.

That's right. Valve body. As in automatic transmission. <Jaw drop.> But, hey, the fact that I wrench on my slushbox myself should mitigate the ignominy, right?

The reason for the removal/reinstallation was to send the valve body out for a rebuild. My vintage 2000 model year Audi S4 had started to develop an irregular heartbeat (i.e., engine revs not holding steady) at lower RPMs. After swapping a bunch of parts with her sister (a 2004 allroad), pressure testing for turbo boost leaks, checking the automatic transmission fluid level, and not solving the problem, I had ruled out the most common causes of this issue. The valve body seemed to be the most likely culprit to try to address next.

Removing and reinstalling a valve body is not a terribly technically challenging job. It requires draining the automatic transmission fluid, removing a number of screws, undoing a few wiring connectors, and putting everything back together and pumping new ATF back in.

The most difficult part of the process by far is the sheer mess. ATF gets everywhere and will quickly seep through even thick cardboard. That extreme permeativity (which may be a word I just made up) is why it's good in transmissions. Despite my best containment efforts, I still managed to get it all over my garage floor. Fortunately I had a lot of Purple Power on hand to clean it up.

I sent the valve body to IPT not only for a rebuild, but also for a performance upgrade that would supposedly make the slushbox less slushy (i.e., produce crisper gear shifts).

Here's the housing under the transmission with the valve body removed:

And here's the valve body in all its glory, back from the shop:

And here's the valve body back in the car:

And here's a fresh ATF filter installed under the valve body:

I used a hand pump to pump the ATF back in. I knew I would have trouble getting the pump's output tube to stay in the filler opening in the ATF fluid pan, so I wrapped a few unwound large paper clips around the tube and secured them with a small hose clamp to create sort of a "gooseneck" and also a hook to hook the tube into the filler opening:

After putting everything back together and filling the ATF to spec, the moment of truth had arrived: The test drive.

Unfortunately, the rebuilt valve body did not solve the problem with the bouncing revs. Since I drive exclusively in the "manumatic" mode anyway, I'll just manage the issue as I've been doing up to now by dropping to a lower gear than I would otherwise select to keep the revs a little higher and out of the lower range that triggers the issue.

The transmission shifts did feel a bit snappier, but still not quite as sporty as a modern "flappy paddle" dual-clutch transmission or even a modern torque converter automatic.

Overall, there is not enough "bang for the buck" for the IPT valve body upgrade for its own sake, but it may be worth trying in an attempt to resolve other valve-body related issues. This verdict is largely moot, however, as I doubt there are many other people still driving Tiptronic Audis of this vintage who would be considering doing this anyway.