Final drive gears
10-05-2017, 08:42 AM
#1
Final drive gears
Can somebody please tell me how to swap from a 3.35 (or whatever I have) to a 3.7/3.9/4.08 something like those? Easy for rwd but how is it done in x platform?
Anybody making custom parts to drop in?
The rear should work from rwd g37 right?
So how do I find one compatible with the front?
thanks for your time, sorry if this has been covered.
(2011 g37x 7speed auto)
Anybody making custom parts to drop in?
The rear should work from rwd g37 right?
So how do I find one compatible with the front?
thanks for your time, sorry if this has been covered.
(2011 g37x 7speed auto)
10-05-2017, 10:27 AM
#2
You will need a front diff to match your rear. You have two options:
3.692 gear ratio; which you can use a front diff from a 2009-2012 FX35, 2007-2008 G35X, 2009-2010 M35X, or 2013-Present FX37.
Or go to 3.133 (38100-AR260). This gearing can be found in the 2007+ EX35 and EX37 AWD models.
I don't recommend 3.133 unless you are going over 500+AWHP. Honestly 3.692 will be fun. Many people have reported loving it for RWD. AWD should be able to hold the power to the ground better at launch, in theory.
I have a spare 3.133 front diff if you want to go that route. If you go 3.692 be sure to get a rear diff with a LSD. It doesn't mean a lot with our AWD but it doesn't hurt either. Just get the whole pumpkin with both and swap them out. You will need to swap out the input flange on the rear diff with the input flange from your old diff. I would replace the seals during the process as well.
3.692 gear ratio; which you can use a front diff from a 2009-2012 FX35, 2007-2008 G35X, 2009-2010 M35X, or 2013-Present FX37.
Or go to 3.133 (38100-AR260). This gearing can be found in the 2007+ EX35 and EX37 AWD models.
I don't recommend 3.133 unless you are going over 500+AWHP. Honestly 3.692 will be fun. Many people have reported loving it for RWD. AWD should be able to hold the power to the ground better at launch, in theory.
I have a spare 3.133 front diff if you want to go that route. If you go 3.692 be sure to get a rear diff with a LSD. It doesn't mean a lot with our AWD but it doesn't hurt either. Just get the whole pumpkin with both and swap them out. You will need to swap out the input flange on the rear diff with the input flange from your old diff. I would replace the seals during the process as well.
10-05-2017, 10:33 AM
#3
I just saw your other post. If you go much higher than 3.692 with our insanely short first 3 gears in our auto box you might start running into drive-ability issues with WHP above 340ish. Just my opinion. I'm sure you have read a few of the threads on the 370z forum about autos with 3.9 and higher ratios.
That said, you would need to get someone to make a custom front ring gear and pinion for our diff. If you go that route you just as well get a LSD put in up front as well. I found two different companies that make custom LSD for our front diff (same as the GT-R diff), but they costed nearly $2k.
That said, you would need to get someone to make a custom front ring gear and pinion for our diff. If you go that route you just as well get a LSD put in up front as well. I found two different companies that make custom LSD for our front diff (same as the GT-R diff), but they costed nearly $2k.
10-05-2017, 10:39 AM
#4
You will need a front diff to match your rear. You have two options:
3.692 gear ratio; which you can use a front diff from a 2009-2012 FX35, 2007-2008 G35X, 2009-2010 M35X, or 2013-Present FX37.
Or go to 3.133 (38100-AR260). This gearing can be found in the 2007+ EX35 and EX37 AWD models.
I don't recommend 3.133 unless you are going over 500+AWHP. Honestly 3.692 will be fun. Many people have reported loving it for RWD. AWD should be able to hold the power to the ground better at launch, in theory.
I have a spare 3.133 front diff if you want to go that route. If you go 3.692 be sure to get a rear diff with a LSD. It doesn't mean a lot with our AWD but it doesn't hurt either. Just get the whole pumpkin with both and swap them out. You will need to swap out the input flange on the rear diff with the input flange from your old diff. I would replace the seals during the process as well.
3.692 gear ratio; which you can use a front diff from a 2009-2012 FX35, 2007-2008 G35X, 2009-2010 M35X, or 2013-Present FX37.
Or go to 3.133 (38100-AR260). This gearing can be found in the 2007+ EX35 and EX37 AWD models.
I don't recommend 3.133 unless you are going over 500+AWHP. Honestly 3.692 will be fun. Many people have reported loving it for RWD. AWD should be able to hold the power to the ground better at launch, in theory.
I have a spare 3.133 front diff if you want to go that route. If you go 3.692 be sure to get a rear diff with a LSD. It doesn't mean a lot with our AWD but it doesn't hurt either. Just get the whole pumpkin with both and swap them out. You will need to swap out the input flange on the rear diff with the input flange from your old diff. I would replace the seals during the process as well.
G35 and m35x are 5 speed right??
10-05-2017, 10:56 AM
#5
No, it does not have to be a 7-speed. Just those year ranges of those AWD chassis came with the same front diff housing as ours. If you want to make sure you are getting the right ratio ask for a picture of the VIN plate in the door off the donor car. The axle info should read RC36 for the 3.692 or RC31 for the 3.133.
Be aware there are other 3.692 front diffs out there but they are different style housing and will not mount to our engine.
Those year G35x and M35x came with the new HR engine that shared the same mounting points and those same diff housing up front as our VQ37VHR's do.
Be aware there are other 3.692 front diffs out there but they are different style housing and will not mount to our engine.
Those year G35x and M35x came with the new HR engine that shared the same mounting points and those same diff housing up front as our VQ37VHR's do.
10-05-2017, 11:10 AM
#6
No, it does not have to be a 7-speed. Just those year ranges of those AWD chassis came with the same front diff housing as ours. If you want to make sure you are getting the right ratio ask for a picture of the VIN plate in the door off the donor car. The axle info should read RC36 for the 3.692 or RC31 for the 3.133.
Be aware there are other 3.692 front diffs out there but they are different style housing and will not mount to our engine.
Those year G35x and M35x came with the new HR engine that shared the same mounting points and those same diff housing up front as our VQ37VHR's do.
Be aware there are other 3.692 front diffs out there but they are different style housing and will not mount to our engine.
Those year G35x and M35x came with the new HR engine that shared the same mounting points and those same diff housing up front as our VQ37VHR's do.
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10-05-2017, 11:41 AM
#8
10% increase in acceleration. Drawback is the 10% increase in RPMs compared to your current speed to RPMs. It's not a 1:1 comparison, but drive around in manual and never use 7th. On the highway, this will be around your cursing RPMs. I switched to 255/285 tires for a little extra help in compensating the gearing (not a huge difference but helps).
The hardest two parts about the swap is swapping over the input flange on the rear diff and dropping the engine to swap out the front. You can get away with only dropping it a couple inches but I couldn't see a way to do it easily without dropping it.
And yep, those two diffs should do it for you. That price for a rear diff is high. You can get a LSD 3.692 diff for about $100 cheaper, shipped, if you are patient and look around. The picture shows the correct front diff, not so much the rear; just FYI (it could just be a generic picture of different diffs). I never checked those models for the same rear diff as ours, just FYI; only front. Most I figured would source the rear from a 370z or G37. You are looking for a r200 rear differential.
The hardest two parts about the swap is swapping over the input flange on the rear diff and dropping the engine to swap out the front. You can get away with only dropping it a couple inches but I couldn't see a way to do it easily without dropping it.
And yep, those two diffs should do it for you. That price for a rear diff is high. You can get a LSD 3.692 diff for about $100 cheaper, shipped, if you are patient and look around. The picture shows the correct front diff, not so much the rear; just FYI (it could just be a generic picture of different diffs). I never checked those models for the same rear diff as ours, just FYI; only front. Most I figured would source the rear from a 370z or G37. You are looking for a r200 rear differential.
10-05-2017, 04:19 PM
#9
I'd skip on the LSD rear diff. I have a rwd with 3.69 rear diff and have no issues launching it. The awd will be even easier. The only thing it may help with is the twisty roads but other than that I would save hundreds of $$$ and get a non LSD rear diff
10-05-2017, 05:16 PM
#10
I just recommend the LSD because 1) if your going to do it maybe, do it right the first time, 2) the price difference isn't that big, and almost non-existent if you hunt long enough (****, I just typed in LSD differential 370z in an ebay search and got three hits, all at least $100 cheaper shipped then the one he posted), but mainly 3) I know the area he lives and we have nothing but twisty roads. We can throw out a 4) the GT-R has a better AWD system and came with a LSD for a reason. But you are actually correct: the odds of it being noticed is limited and opinionated with the AWD. If time and money is key get what you can.
10-05-2017, 05:44 PM
#11
I OP needs a LSD rear diff if he has an auto. At least that's what my tuner told me.
05-26-2018, 10:21 AM
#12
10% increase in acceleration. Drawback is the 10% increase in RPMs compared to your current speed to RPMs. It's not a 1:1 comparison, but drive around in manual and never use 7th. On the highway, this will be around your cursing RPMs. I switched to 255/285 tires for a little extra help in compensating the gearing (not a huge difference but helps).
The hardest two parts about the swap is swapping over the input flange on the rear diff and dropping the engine to swap out the front. You can get away with only dropping it a couple inches but I couldn't see a way to do it easily without dropping it.
And yep, those two diffs should do it for you. That price for a rear diff is high. You can get a LSD 3.692 diff for about $100 cheaper, shipped, if you are patient and look around. The picture shows the correct front diff, not so much the rear; just FYI (it could just be a generic picture of different diffs). I never checked those models for the same rear diff as ours, just FYI; only front. Most I figured would source the rear from a 370z or G37. You are looking for a r200 rear differential.
The hardest two parts about the swap is swapping over the input flange on the rear diff and dropping the engine to swap out the front. You can get away with only dropping it a couple inches but I couldn't see a way to do it easily without dropping it.
And yep, those two diffs should do it for you. That price for a rear diff is high. You can get a LSD 3.692 diff for about $100 cheaper, shipped, if you are patient and look around. The picture shows the correct front diff, not so much the rear; just FYI (it could just be a generic picture of different diffs). I never checked those models for the same rear diff as ours, just FYI; only front. Most I figured would source the rear from a 370z or G37. You are looking for a r200 rear differential.
