I've seen some final drive kits for 6MTs but I was wondering if there was anything available for 5ATs, and in my case for an X with AWD.

Yes I've searched. And I've posted this in the technical forums, almost 50 views and no replies.

ive looked for the samething no luck if u happen to find anything let me know

you have to get the 6 speed pumpkin then use the gears they make for the 6 speed. only way ive heard to do it

I might be wrong on this....but I am pretty sure you cannot just change the rear gears on an AWD vehicle. The Front and rear are a matched set. This is also why you cannot run different height rims or tires as it throws the geometry off and sets a CEL. If you change the rear than the front has to change as well. To the OP, are you looking to change the ratios in the trans iteself?

Yes I'm looking to the change the ratios in the transmission.

VB upgrade..... go on stillen.com

Are the transmissions different in the coupe 5AT and the sedan 5AT? Internally they should be the same. I could be wrong on this of course. The only logical thing I can think of is the X models are stronger internally but that is probably not true. Anyone know if they are the same internally?

I am sure that the transmission is different, because then vin plate has a "transmission type" badged to it, which is different between the g35 sedan and g35x awd. (under hood vin plate). My 06 g35x which i bought brand new, is at 62k in service right now. I had a howel noise/humming come from the rear axle when you go from 40-60 mph accelerating, and only while accelerating. The problem was replicated, and they are replacing the entire rear axle under warranty and will not be done until mid next week.
This was caused because I have run the 19" Rays LMGT4's staggered wheels setup since day-0. The awd light or other warnings never came on or gave a problem.

So you have had staggered wheels with the height tire for 62,000 miles and this is the only issue? I do not believe that the staggered wheels caused the problem. Could be faulty or warn parts. Regardless I am glad that they are fixing the vehicle under warranty for you. Oh and just because the part numbers are different does not mean the internals are as well. The part number could be referring to the actual trans case or some other difference. Manufacturers do very crazy things at times.

I am not an expert but it seems to me that changing only one side of the equation would not be a good idea. Just say that the power is split 50-50. If you change the final drive gear in the rear it would change the power split, wouldn't it? If the car is expecting 50-50 and gets 45-55 I could see some serious problems on the horizon.

Disclaimer: I have no expertise, the above is just a guess.

You are correct except in this instance the Original poster wants to change the ratios inside the transmission itself. Not the rear diff.

I thought that the final drive was in the differential? It must be different in an X. Having to mess with the actual transmission sounds like it will be very expensive in comparison to a final drive change on the RWD G.

Final drive is the combination of the trans and differential.


by the way, changing one differential in an AWD would be catastrophic. It would detect it as one set of wheels slipping and constantly try to correct the problem, and probably fairly quickly destroy itself.