Hi All,

The original G35 automatic transmission had an issue with reverse not engaging, a Nissan 350Z auto transmission was sourced and installed, now the car feels like it has half the power it had before.
The gears change as they should while driving and reverse also works fine.
it feels like there is something holding back the flow or something.
Now to get the trans out, part of the exhaust needed to be removed and i'm thinking something along those line may have been overlooked and need to know where to look.
Is anyone able to provide advise please?
This car belongs to my brother in law who drives it everyday.

Unless there is an issue with the Trans that was installed, I don't see what other problems that can be directly related to the swap. Are you sure the z trans was in working order when it was pulled. The only other possible culprit is the transmission module or the ECM isn't recognizing something. Is there a check engine light on?

When you connect a different transmission up to the TCM like you did you will need to take it to the dealership and ask them to flash the EEPROM on the Valve Body. EEPROM is only written to 1 time and that is at first startup. So when you change transmission your TCM is looking for the valve body from the previous trans.

Have them flash the Valve Body and the TCM and you should be good to go.

RED_DET wrote:Unless there is an issue with the Trans that was installed, I don't see what other problems that can be directly related to the swap. Are you sure the z trans was in working order when it was pulled. The only other possible culprit is the transmission module or the ECM isn't recognizing something. Is there a check engine light on?

No, no check engine light on
We're pretty sure the replacement trans is good

tollboothwilley wrote:When you connect a different transmission up to the TCM like you did you will need to take it to the dealership and ask them to flash the EEPROM on the Valve Body. EEPROM is only written to 1 time and that is at first startup. So when you change transmission your TCM is looking for the valve body from the previous trans.

Have them flash the Valve Body and the TCM and you should be good to go.

Thanks, we will see if anybody in Sydney knows how to do this.
I'll come back and let you know how we go

Just out of interest, is flashing the VB and TCM something i can do myself with ease?

no. it must be done at a NISSAN or INFINITI dealership using the CONSULT II. I typically avoid them at all costs, but its a must when you swap different Valve Bodies for proper function.

All, bit of an issue, the mechanic we took the car to has cleared all the error codes, he has been voltage testing here and there and has noticed the intake manifold butterfly is not opening up all the way, he said that it is only giving him around 1.6 volts and when he manually pushes it open all the way that it reads around 4.6 volts.
My question is: is this a result of not fully flashing the VB and TCM or is there something additionaly wrong perhaps with the butterfly itself?
Thanks all for your help so far

Those things are very sensitive...most likely it is damaged.

IT IS FROM NOT FLASHING THE TCM AND VALVEBODY. You can only do this with the CONSULT II and i've never seen anybody outside the dealership buy this for kicks and giggles.

It shouldn't cost that much - will only take them 5 min to flash.

Thats what i thought Willey, just to update, we have had no luck with this just yet, we're still looking around and making phone calls but nobody has any experience with these cars in Sydney that we've found.
Will keep you updated.

any NISSAN or INFINITI dealer should be able to do it

the other option is to swap the Valve Body from the old trans into the new one - since its already paired with the TCM it should work as is should.

tollboothwilley wrote:any NISSAN or INFINITI dealer should be able to do it

Nissan should but they don't want to take on the responsability as soon as they hear the car is an import just in case they break something i guess. There are no Infinity dealer in Australia

tollboothwilley wrote:the other option is to swap the Valve Body from the old trans into the new one - since its already paired with the TCM it should work as is should.

Thats the best idea i've heard about this issue so far, is it something someone with basic garage tools can do or does the mechanic who did the swap need to do this? We have limitted machanical skills but if its not too hard of a job then we're willing to give it a go.

Hrm...well all you really need is an oil drain pan to catch the trans oil and a 10mm socket set. However - with any valve body its a lot of different sized bolts. Just doing a swap of VB's should only be 3 different sizes though. 12 bolts in total I believe.

http://www.gtmotorsports.com/pdfs/produ ... VB_RnR.pdf
Read through this and follow this carefully. You will be draining your trans fluid - if its clean you can reuse if you want. Personally, I would call this a perfect time to do a flush anyways. You will get 7-8 quarts out normally..

We had no choice, there is no skill for these cars here in Sydney, The Valve Body was swapped then everything was put back together and the car is now working as it should.
All the time we spent looking for someone to flash it we thought would be better spent here.
Thanks especially to Willey for the resolution, it can't be easy being that good..

Good deal!!!

TBW to the rescue!!!!!

SaViOr wrote:We had no choice, there is no skill for these cars here in Sydney, The Valve Body was swapped then everything was put back together and the car is now working as it should.
All the time we spent looking for someone to flash it we thought would be better spent here.
Thanks especially to Willey for the resolution, it can't be easy being that good..

Its a tough life...LOL

Glad you got it done and have the car working again. you should have just installed the Transgo shift kit while you were at it - since you already had the VB out of the car

Oh well, next time

Hello,
I replaced the circuit board on the valve body in my 06 G35. Car starts and idles nice, but I have no acceleration at all! I can use some advice.

The "circuit board" you're referring to is the TCM. If it isn't flashed with the right firmware then the trans will be permanently limp. You should be able to have the dealer perform a "new blank" programming sequence on it using the ROM-ID for your VIN number, which will assure the firmware matches your original TCM. However, you may have opened a can of worms. Those circuit boards are part of the Valve Body and are calibrated to the VB they're attached to. They're not meant to be swapped to a different VB. One that is swapped may never perform correctly, even with the right program on board.

Thank you for responding! I've changed that part twice b4 and car ran great afterwards. Got lucky I guess. What your saying makes sense. Guess I'm having it towed to dealer! Thanks again!