Hello Everyone!
I just wanted to share my transgo shift kit experience with you and see if anyone else had experienced anything like this-
2 weeks ago, I installed a transgo kit in my 03 G35 sedan. The install went just fine: it was a long process but the included instructions were pretty good.
Anyway, I filled the transmission up and took it for a drive and things got weird. It would hesitate, shift slow, clunk into gear, and act like it was gear-hunting. I shut it off and let it sit for a half hour and tried again. This time, the 2nd-3rd shift was a car-rattling BANG, even with just a tiny bit of throttle input. This continued over and over, so I just gave up testing and parked it.
The next day, I pulled my battery cable to reset adaptive shift and went for a drive and amazingly, the 2-3 shift had chilled out a bit. It was still harsh, but better.
My joy was lessened I then discovered that flooring it in 5th gear created a major bang when it downshifted into 3rd. CRAP!
Aside from 5-3, the rest of the shifts have steadily improved and the 2-3 has softened. I figured that maybe I confused the TCM by romping on it after the adaptive shift reset so after a week, I pulled the battery cable to reset it again. This time, I gradually increased my throttle application over a 100ish mile span of driving and all of the shifts have gotten to be perfect...except 5-3.

My conclusions are:
-no matter what Transgo says, you need to pull the battery cable to reset the TCM before driving with the shift kit
-drive conservatively (and progressively harder) over lots of miles to let the transmission figure out ideal line pressures for each gear through adaptive shift.

I have not been able to figure out the 5-3 downshift bang so does anyone have insight into why that might be happening? My trans never did that pre-transgo and it only has 78k miles.

 

Have you checked your fluid levels again? What ATF are you running?

 

I checked it the next day after my first test and I was good on the fluid level. All in all, it took 7.5 Quarts total.
After researching some fluid options on various forums and Bob is the Oil guy, I picked M1 Synthetic ATF. Do you think that is the issue here?

 

Could be the fluid. I've heard these transmissions are very picky about what ATF you use.

I read up on bobistheoilguy too, and it seems Castrol makes the Matic J for Infiniti/Nissan. So I use Castrol Transmax Import Mulit-Vehicle ATF.

No issues. Used it my old Benz as well, which was also very picky about ATF.

Obviously, Infiniti does not have their own oil refinery, so somebody has to make there ATF for them. Apparently, that is Castrol.

I kind of want to do the Transgo kit mod, but stories like this scare me away from it.

 

Even if it it isn't the root issue, I am wishing I went with Castrol now.

I do think that the transgo kit really works wonders for the laggy stock shifts but I suppose it is better safe than sorry, especially in a DD. I really miss the ease of which I was able to tune my old GM auto trans, all electronically.

 

Hi Guys,
Sorry to dig up an old thread but I have a little more to add to the story now-

I picked up an 04 TCM for $25 used. My thought was that I had somehow really screwed up adaptive shift on the old one so why not go with a newer one with later programming?

Anyway, I installed it and quickly noticed that the shift logic is significantly better for most driving conditions but the 5-3 bang remains.

I just wanted to let people know in case they try the same thing. I still have yet to change the fluid to Castrol as recommended since I really don't want to ditch my $65 worth of 4000 mile old fluid but I will let you know what happens when I do.

 

wow. you did the install yourself. I was afraid to do it b/c i always think i would have problems with it. So i took it to a shop that specializes in it. Got the car back 2 days later and it was super awesome. car shifts hard and super fast.

 

Honestly, it wasn't too bad, I just took my time (about 7+ hours). I did it myself for budgetary reasons and I found that the trickiest parts are keeping the check ***** in place on reassembly and unbolting and bolting in the HEAVY valve body from the transmission.

 

After putting about 9K miles on the Mobil 1 Synthetic ATF, I finally got tired enough of the 5-3 Bang shift to change out my nice, pricey, clean fluid
I drained the pan and the cooler lines and filled it with 5 qts Matic S (available locally @ $8.80/qt) and the bang shift is almost completely gone!!!
What I mean is that it is more of an occasional small bump now, not a bang.
So my happy conclusion is: GET MATIC S (or ditch M1) if you are having wacky post-kit install shifting. As I get more of the M1 fluid switched out from the next drain and fill, the bump shift will probably dissappear.