I recently got a transgo shift kit installed back in April on the Auto-transmission of my 03 Twin-Turbo Infiniti G35 Sedan. I've noticed a huge power gain as I'm able to get more agressive shifting between gears. From a 0-60 take off, you can actually hear the tires chirp when you floor it all the way. It's not a bad upgrade at all for about $3200 for parts and labor ....My transmission had actually gone out on me (5th gear was free wheeling; hard jerking between 2nd and 3rd) which is why I considered the upgrade.

Yesterday I removed my (+) positive terminal on my battery to install a new 500Watt audio amplifier for my speaker box in my trunk. After I finished installing the amp, I plugged the terminal back on the battery. I took my car for a little test drive around the corner to test out my speakers. When my car was shifting up from 2nd to 3rd gear, there was a very harsh (unusual) jerk. I could also hear a weird jerk noise below the car. I'm not sure what caused this to happen again...Did unplugging my battery mess something up with the TCU, or do I probably have some sort of ground issue? The amp is grounded directly to the frame of the car, and powered by a 12V (+) connection coming from the battery and to the trunk.

I took out the amp today and took another test drive, but my car is still shifting real harsh between 2nd and 3rd. All other gears shifting is fine, and its fine on the downshifts. I've also tested using the manual sports shifter and still have the same jerking problem from 2nd to 3rd gear.

Has anyone else experienced this problem with the transgo shift kit or Does anyone have any suggestions? Tomorrow I am calling up the transmission guys who worked on my car to see if I can have them take a look at it.

 

Let us know what the tranny people say. But I hope it's just the TCU relearning the logic.

 

This has happened to a few other members that unplugged the battery. After a day or two, the TCU relearned the TransGo

 

This was no ordinary jerking...it felt like my tranny was going to explode. Some of the posts I searched on this forum describe it as "boom" shifting between the gears. I didn't want to risk any parts going bad so, since my tranny is under warranty, I took it down to the tranny shop to have it looked at.

They told me they needed to relearn the TCU since the memory was gone after unplugging the battery. Something they said was common with Nissan/Infiniti's losing the ECU/TCU memory once the battery is unplugged. They recommended that I purchased a Power Supply to Vehicle Memory Saver from a local auto shop that would keep the vehicle's ECU/TCU memory after unplugging the battery.

While my tranny was pulled, they took a look at all my internals and said everything was good but saw that I had a few hot spots on my clutch. Because of my twin turbo setup, the shop recommended a clutch pack (from Alto) and a valve body upgrade (Sonnax). Since my tranny was under their warrantly, they only charged me 240 for the clutch pack and 412 for the valve upgrade.

I just got my car back last week and it's driving great. I definitely will not be touching the battery anymore...

 

Weird, they upgraded which valve? There are 6 or 7 on the valve body

 

The 5ATs are known for hard shifting between 2nd and 3rd. Mine does it, always has, and a lot of Driver members have experienced the same issue. I'm glad your issue seems to be worked out.