G37S 3.69 VLSD Rear Diff Upgrade - Cliff Notes 2006 M45 only

[ken in az]

This mod is pretty darn easy if you have an impact gun

Use my other posts on this topic for pictures as I have new info that makes life easy.

Step 1 - Procure a 2008 G37S rear differential and axles.Step 2 - Remove stock differential and axlesStep 3 - Remove front companion flange from stock diff and swap it too the G37S differential. This is where the impact gun comes into play. Be careful when torquing down campanion flange nut not to overtorque it as this could adversly affect the pinion depth. Normally you can get away with doing this procedure 2 to 3 times before needing to reset the pinion depth with a new crush washer.Step 4 - Adjust the axle length to match the stock m45 axles by loosening the metal straps on the boots to the inner CV shaft. Then pry up on the seal just enough to allow air in/out whichever is needed. The boost are air tight and are stiff enough to create an air tight seal and act like an air spring to retain a certain length.Step 5 - Install G37S differential and axles and torque to specifications and use new cotter pins where necessary.Step 6 - Drain and fill axle fluid with your choice of axle lubricant. I recomend severe gear 75-90w by amsoil.

Step 7 - Enjoy your new car as this simple change makes your car times 10 more fun.

This may work for later year M45's and M35's but I have not verified as such.

2 negatives I have experienced.#1. Slightly less gas milage. I have only ran 2 tanks though since the swap, 1st tank was with me beating on it quite a bit 18.7mpg. 2nd tank I was at 19.7mpg when I dropped it off at the dealership today. I watched them let it idle for close to 10-12min, whan I got it back it was at 19.0mpg and finished the tank at 19.3mpg. I notice that I get better mileage at slower speeds but once I am over 70mph I struggle to get 20-22mpg on the freeway. overall I would say that freeway driving has the most affect on mpg's but not as much as some have claimed. I'd be confident that it's a 1mpg drop hwy and if it were cty only you'd see 1mpg improvement. That is if you can keep your foot out of it. I also have the headers installed but man, when I have my foot in it the dang thing seems to drink the fuel alot faster than before.

#2. Cruise Control. The cruise control now will not set at anything higher than 65mph! This is because the cruise control is reading speed from the transmission output shaft speed sensor. Wheel speed is unchanged but now the driveshaft is spinning faster at the same rolling speed. Long story short the cruise thinks it's going 85mph which is the limit of the stock cruise control. - "Can this be fixed?" potentially yesby installing a dakota digital sgi-5c calibration box. I will be attempting this soon.

"why did you say you had VDC OFF, SLIP, RAS indicator lights on the dash in your last post?" This is because with the installation of the headers I upset the steering angle sensor. A trip to the dealer to zero it out and all is well. My mistake caused this. No more lights on the dash.

Happy Motoring!

[saeedakobiakov]

let us know how fast really car is in 1/4.show me what you got?i am a little jealous obviously.i wish i could do the lsvd to mine.it's just too many mile to play with it at 91k. i still happy with my track results.thinking of 03 04 m5 - 6sp. faster ,ultimate driving machine, that's what they say.i will keep mine for now. needs struts/mounts.enjoy yours while it lasts.caug

[ken in az]

let us know how fast really car is in 1/4.show me what you got?i am a little jealous obviously.i wish i could do the lsvd to mine.it's just too many mile to play with it at 91k. i still happy with my track results.thinking of 03 04 m5 - 6sp. faster ,ultimate driving machine, that's what they say.i will keep mine for now. needs struts/mounts.enjoy yours while it lasts.caug

I screwed up - the last street drags was last friday so I have to wait till next year when the track opens again.

I'll do some logs to 120mph and we'll see what the time to 100mph is and if its faster than before.

[marosari00]

Ken,I like what you did.

Did you consider replacing the internals on the original differential? Like a Quaife LSD...?

Manuel

[ken in az]

Ken,I like what you did.

Did you consider replacing the internals on the original differential? Like a Quaife LSD...?

Manuel

Yes and no....

- Yes because I wanted the LSD

- No because of cost and I wanted to change the gear ratio.

Quaife LSD = $1200 + installGears = $500 + install

I got nearly the same thing for less than $400 and it was a direct swap - still have the old parts.

[dvan]

I screwed up - the last street drags was last friday so I have to wait till next year when the track opens again.

I'll do some logs to 120mph and we'll see what the time to 100mph is and if its faster than before.

Any updates Ken?

[ken in az]

been lazy and the track hasn't been open yet....i'll try and do some logs tonight

[ken in az]

Again - sorry guys....track was open on friday but they didn't have the schedule updated till after I had already made plans.

Next track day is a drift and drag event on the 29th - gonna throw the old skins back on in the rear and see how it does in both events. Hopefully get some good sideways shots

I can already tell traction will be easily lost on the drifting track but I'm not sure how it'll do on the launch for the 1.4 mi

For giggles I might throw on the bottle and play just to see what it does - haha!

[mexillis]

Ken, do the G37S diff. only work for the M45? Also have you added the dakota digital sgi-5c calibration box yet to fix the cruise control? One last question can u do a brake stand now? lol

[ken in az]

Ken, do the G37S diff. only work for the M45? Also have you added the dakota digital sgi-5c calibration box yet to fix the cruise control? One last question can u do a brake stand now? lol

I have not done the dakota digital box mod yet. I might not even mess with it to be honest - I rarely use cruise control.

I don't know about the compatability with the M35, I know it will work but I don't think you need the axle shafts....it should just bolt in and the M35 axles should work. "should" being the key word there because I have never stuck my head up an M35's butt to see.

Oh and brake stands - I just unplug the brake switch connector under the dash. If you have have a place to go where you dont need brake lights, just look up under the dash at the connectors on the brake pedal. there should be 2, one white and one brown, and unplug the white one with 4 wires. Before you do that though, make sure the car is running and the transmission is in neutral with the ebrake on. Otherwise you cant start the car or take it out of park - lol Then just brake stand burnout all day long

For me, I can mash the gas, light em up so much and shift to second gear and continue the burnout into second gear up to redline burning posi. good times

[EniGmA1987]

Did you buy your rear differential from Infiniti or from some other place?

If I have some spare money lying around anytime soon I am thinking I might try doing this on my M35

[mexillis]

i ment if the differential has to be from a G37S or can it be any G37? possibly G35?