Does anybody know if the 2007-2008 5AT transmission that was used in the G35 SEDAN will fit in the 2004.5-2006 sedans or the 2004.5-2007 coupes that use the automatic?

I was looking over the specs and when they upgraded the 2007 to the HR motor they not only changed the final drive (3.692) but they also changed the gearing in the 5AT to more aggressive gearing in 1st, 2nd, and 3rd gears.

This will not work for the 2003-2004 guys such as myself due to the TCM and Valve Body differences but if they kept the VB the and wiring the same in the 2007 & 2008 then that would be an upgrade option for the 5AT guys.

It shows you that Infiniti really decided they wanted better gearing in the 5AT as they increased the FD from 3.35 to 3.69 AND the transmission (2.5 vs 2.8 in 1st gear)

 

Keep in mind the second gen HR cars are quite a bit heavier, have 1" taller tires (reduces gearing), and the HR powerband is much higher in the rev range. Without increasing gearing, the 2nd gen cars would feel pretty lethargic until 40mph+.

Regardless, I'd take that extra gearing in 1st, 2nd, and 3rd

 

finding the later trans might be hard though... I doubt anyone would want to swap

 

I would want and even TRY to swap if it were feasible - however it would require swapping all the internals in my case and thats just more work than its worth. If I had the 2004.5 TCM/VB I'd look into it more seriously.

You keep the 4th/5th gears so you don't sacrifice MPG when cruising at all.

 

I mean I doubt a 2nd gen would want to swap - meaning; it would be hard for us to find a 2nd gen transmission... I suppose there could be salvaged available, but it's still kinda early to find those.

 

i'm sure you can find a 2nd gen trans. Not that hard. I have a few people I talk to when I'm looking for parts. They always seem to have something.

 

I found 5 5ats from 07 HRs within 400 miles of Kansas City www.car-part.com. Prices ranged from $800 to 1300.

 

are the transmission direct drop ins. Do any sensors or harnesses have to be changed?

 

I didnt realize they'd be so readily available... you'd hafta add a couple-few hundred for shipping - then gotta deal with getting rid of old trans... not worth it for me (even without shipping)... but maybe someone will pioneer the concept and go for it ~

 

I've got a 2006 5AT with 12K miles on it if anyone wants it (for a spare?)

Shipping is only gonna be around $100-150 depending on where you ship from/to for a trans. They are pretty light for transmissions.

There still needs to be more research done to find out if nissan kept using the same TCM/valve body in the 2007-2008 5AT but my guess is that it probably has the same with just a different flash on the TCM.