It was easy. I just glanced at the aforementioned instructions and went to work.
- Remove floor mat (unsnaps at the rear)
- Pull back carpet in foot well
- Cry about "Daimler Chrysler" branding on carpet
- Remove foam. It just lifts out.
- Remove 3 10mm nuts. These might be plastic nuts like the ones that hold the wheel well liners in. Two on the bottom (the right one is not visible so you go by feel - it's kind of partially buried under the carpet) and one on the top.
- Sort of fold the metal module carrier away from the firewall and lay it down backwards on the carpet that's folded back.
- This exposes several modules.
- Here are some
- Here's the TCU
- Remove 2 8mm bolts and the TCU just comes free of the metal panel
- Remove both plugs
- Install new TCU and button it up the opposite way it came out. It really did take less than 10 minutes.
I was going to test it and check for codes and stuff before putting everything back together and putting my tools away. Ain't nobody got time fo' 'dat.
Washed hands, went for a drive. Of course it was warming up so I was gentle for a bit.
I did confirm that I do now have four transmission modes instead of the stock three. Stock I had C(omfort), S(port) and M(anual). This new tune adds A(gility) which I guess is something that AMG did in some special models? So this guy sort of took that and turned it up even further. Agility supposedly does not do learning of your driving style (for consistency) and shifts the firmest/quickest. Holds gears more aggressively and so on. Comfort is sort of like before, and maintains the second gear starts. Manual does respond more quickly to the shift paddles. Sport is probably going to continue as my daily driver mode. I only briefly tried Agility and I don't drive the car on full kill much (you can't) so I suspect this will be something I use to show passengers or something.
So digging deeper into Sport. I drove the car maybe 15 miles so the adaptations are still learning and the shift feel will probably change as that happens so this is really just an initial report.
I think the TCC behavior does feel a little different as he said he was going to tweak some things there. I don't know if it's "better" per se but at least different. The SC clutch engagement jerk off initial tip in does actually seem less noticeable though the engagement if you get on it in 2nd is still there (and that's only if you didn't already engage it in first by throttle position). I do feel like the tuning may overall result in less jerky SC engagement which is nice.
At light throttle the shifting feels pretty similar to before. Maybe a little quicker but nothing harsh or noticeable. But when you start dipping into the throttle, it sure makes a big difference, as I had hoped. Basically the shifts transformed from this kind of slow but smooth slipping to a pretty quick and positive shift. It kind of feels like an old school transmission with a shift kit (in a good way) and with the muscle-nature of this car I think it really suits it. I would say downshifting is also more responsive. I punched it from a 40 roll (it must have been in 4th or maybe even 5th) and seemingly almost instantly it went to 2nd and simply took off. That got a grin.
So I look forward to putting more miles on this TCU and having the adaptations learn in so I can feel what the final product is, so to speak. But so far so good. Certainly worth the money.
I did ask the tuner about trans wear. I basically asked if this more positive shifting with reduced torque management would lead to more wear, or perhaps less wear due to less shift overlap. Turns out the latter was correct. Here's what he had to say:
Adaption period is needed. Trans will have less wear. Reason Mercedes was heavy handed with torque reduction was for needing smoother shifts and make gear box last longer with slipping smooth shifts. Making trans shift firmer would make luxury car not so luxury and get complaints. I don't eliminate torque management. its reduced and changed to match firmer shifts. There will be less wear but since its a clutch to clutch transmission trade off is feeling shifts more and makes for faster shifting and less feeling of that let of the gas feel during shifts.
All good news, really. Also, the guy actually responds to my random e-mails. That's worth something, too. He confirmed again that this is a clutch to clutch transmission. I mentioned this in my general E55 thread. That was pretty advanced for a 1996 transmission design. GM's first clutch to clutch was the 6L80 in 2006 and 6L50 in 2007. It means no bands, only clutches. For all I know this now shifts like a 6L80 with a decent trans tune on it.