G37S Diff Comparo for M45 Pics

Post by **ken in az** » Sun Nov 29, 2009 3:05 pm

Both the M45 and the G37S use a common differential called the R200 which refers to the 200 millimeter Ring gear diameter (nearly 8 inches). The M45 2006 model utilizes a 3.357:1 ratio where the G37S uses a 3.692:1 ratio.

Switching from the Stock M45 differential to the G37S ratio is an obvious mechanical advantage to aid in acceleration mainly helping a cars ability to leave the line harder to help 60 ft times. After that there really isn't much a difference in acceleration except you spend a shorter amount of time in each gear.

Here are the pics of the differences involved in the swap.

M45 Axle shaft is the short one

M45 Axle shaft is longer

M45 on the right

M45

G37S

Mark the driveshaft orientation to the diff companion flange

M45 Driveshaft flange is 6 bolt

Remove companion flange - impact gun is a near necessity

M45 Flange on left

M45 flange bolts up just need to clean it up and lube the mating surface with gear lube

Switch is easy as 1, 2, 3

I'll be test driving the car tonight to see if everything works as planned, but that is it in a nutshell. Pretty darn easy!

Post by **DRIPS** » Sun Nov 29, 2009 3:39 pm

Nice! Let us know how it goes. ALso, what was the cost of the swap? Total time to do the swap?

Post by **ken in az** » Sun Nov 29, 2009 3:43 pm

DRIPS wrote:Nice! Let us know how it goes. ALso, what was the cost of the swap? Total time to do the swap?

Took me about 4hrs but could have done it faster.

Cost - don't expect to find a diff for this price - I was very lucky

G37S diff = $199Axles = $199

Post by **ken in az** » Fri Dec 11, 2009 9:22 am

***A Small update***

The inner CV joints from the M45 to the G37S are not compatable. The G37S spline count is less and slightly smaller diameter. This in not a bad thing though.

I took them out of the car and realized how much room there is for movement and there ia pleanty of room left in the G37S inner CV joint to accomodate the M45 suspension travel.

When I first installed them the short side was too short and the long side axle was too long. Thjis was an easy fix because when i reinstalled the boot I realized they make the CV joint air tight. So when I installed the longer axle it compressed the joint creating positive pressure inside the joint like a balloon. I simply let out some air and they now fit like a charm.

So to conclude:

G37S Rear axles are 100% compatable when using the G37S rear differential.

I still have not been able to get my VDC OFF, SLIP, RAS lights to turn off. I'm going in to get the STeering angle sensor zero'd out on monday to see if that helps and if it doesn't I have ordered the Dakota Digital SGI-5c to recalibrate the transmission speed sensor.

Post by **jazzy m45** » Sat Dec 12, 2009 4:41 pm

ken in az wrote:Pretty darn easy!

Says who, did Einstein just get ASE certified?

Let us know what results you get in performance gains!

Post by **seymore4** » Sun Oct 14, 2012 1:23 pm

Awesome DIY, did you ever get the lights to go off on the dash? Or just deal with them?

Post by **KoMikeey** » Sun Oct 14, 2012 2:36 pm

so if i got my car uprev'd and get this g37 s rear diff would i have to go back and retune the shift points?

Post by **seymore4** » Mon Oct 15, 2012 3:29 pm

Uprev cannot change the shift points, all it can do is bump the line pressure and influence how the torque converter locks up. None of that has anything to do with the rear dif however so you'll be fine

Post by **KoMikeey** » Mon Oct 15, 2012 4:52 pm

uprev there are transmission shift points arent there. and upgrading the g37 s dif doesnt it change the shift points?

Post by **seymore4** » Mon Oct 15, 2012 5:03 pm

KoMikeey wrote:uprev there are transmission shift points arent there. and upgrading the g37 s dif doesnt it change the shift points?

No and no.

Post by **EniGmA1987** » Mon Oct 15, 2012 8:09 pm

Changing the rear differential will not alter where the computer has the shift points set at, but you will get to those points slightly faster

Post by **clintguy** » Mon Mar 11, 2013 9:15 pm

I am interested in going this route with my 2007 M45.

Two questions:

1. For the rear G37S axles, does it matter if they're from a coupe or sedan?
2. Do you also need a G37S drive shaft?

Thanks!

Post by **clintguy** » Tue Mar 12, 2013 8:20 pm

Can anyone please help with my questions above or point me to a helpful resource?

Thanks.

Post by **mexillis** » Tue Mar 12, 2013 8:34 pm

For #1 i believe it doesnt matter and no for #2.

Post by **Ilya** » Tue Mar 12, 2013 8:36 pm

You have to be a little patient. I've been on this board for a while and this is the first time I've even seen this thread. It's clearly not a common thing done to these cars. Posting in the thread twice in one day isn't going to help.

Post by **built2makeit** » Wed Mar 13, 2013 3:02 pm

am i the only one who has no idea what's going on?

Post by **EniGmA1987** » Wed Mar 13, 2013 5:07 pm

^^^^^ Pretty much

Ken has not been active for a LONG time now, but I *think* he still gets an email update for replies to this thread. So he may actually show up and give some answers for you.
I dont remember if the issue of the VDC, RAS, and SLIP lights was ever solved on the M45 but I have this mod (and the exact piece Ken used to do this since he sold it to me) and I have no errors or issues at all on my M35. I have been running this G37s rear differential for about 3 years now. I believe I still have the G37 axle's if you want to buy them off me when you do this mod, they are not needed if you do this on a 35.

Post by **clintguy** » Wed Mar 13, 2013 9:51 pm

Thanks, mexillis and EniGmA1987.

I did my best to stalk all of Ken's old posts, and I recall reading somewhere that he did fix the lights issue. But I also thought I saw some mention about the drive shaft too. Cool. At least I get to save a couple hundred bucks by not needing that!

I picked up the rear diff and axles last night. I am also going to get a Transgo installed... and, oh yeah, try the 4.083 gear in the M45.

Post by **mexillis** » Sun Mar 17, 2013 2:40 pm

Where and how much? What Nissan did you get the 4.08 gears from?

Post by **clintguy** » Fri Mar 22, 2013 10:35 pm

I picked up the rear diff and axles for ~ $540 on eBay.

I grabbed the ring and pinion for $490 from Fontana Nissan.

Post by **sergofast** » Tue Dec 01, 2015 8:36 am

ken in az wrote:***A Small update***

The inner CV joints from the M45 to the G37S are not compatable. The G37S spline count is less and slightly smaller diameter. This in not a bad thing though.

I took them out of the car and realized how much room there is for movement and there ia pleanty of room left in the G37S inner CV joint to accomodate the M45 suspension travel.

When I first installed them the short side was too short and the long side axle was too long. Thjis was an easy fix because when i reinstalled the boot I realized they make the CV joint air tight. So when I installed the longer axle it compressed the joint creating positive pressure inside the joint like a balloon. I simply let out some air and they now fit like a charm.

So to conclude:

G37S Rear axles are 100% compatable when using the G37S rear differential.

I still have not been able to get my VDC OFF, SLIP, RAS lights to turn off. I'm going in to get the STeering angle sensor zero'd out on monday to see if that helps and if it doesn't I have ordered the Dakota Digital SGI-5c to recalibrate the transmission speed sensor.

Sorry to raise this from the dead but I read in one of your other post that the G37s dif is a direct swap for the m35 guys. Couldnt you use stock m35 axles with this swap in lue of G37s axles?

G37S Diff Comparo for M45 Pics

G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics (ken in az)

Re: G37S Diff Comparo for M45 Pics (DRIPS)

Re: G37S Diff Comparo for M45 Pics (ken in az)

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

Re: G37S Diff Comparo for M45 Pics

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