As our cars continue to climb in age, the frequency of 7AT transmission issues I see posted here and in the G37 Reddit sub (more frequently in the Q50 sub, despite the car being newer) have increased over prior years.

As I prefer to stay in front of potential issues with a solution, I have been looking into whether it makes sense to perform a VR30 transmission swap: https://www.myg37.com/forums/engine-...torsports.html
or
Rebuild my original transmission and add performance enhancements like upgraded torque converter, flex plate (if you ever plan to go FI), valve body and clutches: https://www.myg37.com/forums/g37-sed...placement.html (Post #11)

Both upgrade paths are large financial investments, so I also continue to look around for individual solutions that address the three main failure areas within our transmission:

1. The transmission shares the same radiator/cooling path with the coolant. The passages within the OEM radiator break down and coolant gets into the transmission fluid. Rust, clutch failure and hydraulic issues along with failure are eminent. A full rebuild is then needed. A new radiator or external trans cooler which bypasses the radiator are the only options here if you are trying to be proactive.
2. Riveted torque converter (TC) construction. If you look up the upgraded IPT Trans TC, there is a video on the page where John (owner) breaks down the RE7/7AT TC and explains why they fail. If I had to replace, I'd leverage IPT or Level10 and have them build in a slightly higher stall in the 3K RPM range. Level 10 may be my preference since they offer a core charge return process for convenience along with different options for stall speed. I'm not sure if there are any good OEM Nissan replacement TC companies out there, but I can keep my eyes open and update this post if I see one referenced that I can then talk to on the phone.
3. TCM/Valve Body failures caused by excessive heat (dreaded "output speed sensor" code) Our RE7R01A 7AT runs hot, and neglected fluid amplifies the heat issue and causes a breakdown of the internal TCM (PCB/electronics). Many other brands put the TCM inside the car near the ECU, but ours unfortunately is inside the transmission and prone to wear caused by excessive heat. New OEM assembles come as the valve body and TCM, so they run a little more than 2K with shipping and tax. Another option is used and aftermarket, but there is no clear winner I have seen Till now. Here, I saw a company recommended on Reddit that appears to be popular with the Q crowd for replacement TCM/Valve Bodies.

Nexenzo (El Monte CA/LA): https://www.nexenzo.com/collections/all

I spoke to Justin (Owner, Engineer by training) and he shared with me that he was initially repairing Ford transmission electronics, but he then had several people approach him about performing the same service on the JATCO RE7R01A Nissan transmission. He then spent several months learning the TCM and associated electronics and built a test setup for the TCM (PCB issues are the main problem he sees, things like badly burnt or broken traces). Now over 50% of his business is from Q Owners (now sells several thousand TCM/Valve Bodies per year)

He sources used TCM/Valve Bodies and tests/repairs the electronics, then rebuilds the valve body with OEM quality components and sells for $649 with a 30 day warranty (if professionally installed). No core charge, but if you send him your old TCM/Valve Body, he will refund you $60. In addition, he can program to your car as well if you provide the VIN. Good guy, so I thought I would share my experience in case any of you run into Valve Body/TCM issues.