06 M45 Sport, LSD or Open Dif?

[DeanM45]

I am planning on changing the rear end fluid on the M today and I have been reading on various sites about how the 06+ M's do NOT have a LSD option.

This was interesting to me as my car launches hard and nice and straight. Always thought it has a LSD. I have always thought my car was a bit "special".

Did a few tests. Short little romp from a stop and then pulled up a bit:
Passenger:


Driver:


Rear:



Then, jacked up the car to drain the fluid---car in neutral spin a rear wheel and the other wheel spins in the same direction.

All of this is indicative of a LSD. I am just going to drain and refill (with Redline 75W90 Synthetic).
Can anyone confirm that LSD was an option on the M45S? If no one can confirm, the next time I do some work under the car I will pull the rear cover off and take a look at what rear is in there. I KNOW Cusco makes a type 2 LSD that fits in the Fuga/M Y50 pumpkin.

[DeanM45]

LOL, I'll thrown some 30's on the back with Hosiers and turn it into a drag car!

[CPJ LB]

Not sure, but a fellow member KenAZ I believe did some major mods on his 45 that included swapping out the rear diff... I can't find the post

[JoshTex]

I agree, those are 2 signs indicative to an LSD. I have an addition to that question, will the 3.69 gears from an g35/37 rear fit an M35/45 rear? Meaning, can you swap them into an M Rear?

[DeanM45]

I agree, those are 2 signs indicative to an LSD. I have an addition to that question, will the 3.69 gears from an g35/37 rear fit an M35/45 rear? Meaning, can you swap them into an M Rear?

Looking at the Nismo catalog it says that they share the same R&P gear set (size and bolt pattern). That's a really good question as if I do not have a "stock" differential I wonder what gear set I have. That will be a check when I have the car off the ground again (count the number of tire rotations for one driveshaft rotation).

I believe that the rear had 80W140 in it as it was pretty thick coming out and very, very dark. The magnet on the drain plug was pretty saturated with clutch material (like what you see in the bottom of a transmission pan). Definitely a LSD, two four or so foot long stripes punching it on the street. I forgot that I had done that "test" before. Forget stuff in my old age, LOL. Interesting that even with traction control off, stability control apparently kicks in and over-rides (throttle cut).

Someone else get out there and floor it and let me know if we all have LSD!!

[CPJ LB]

Come to think of it, another mbr with re M35 swapped out the rear diff with the G35 LSD.... I believe it's "Enigma".... He may have picked up the diff from KenAZ... The search function is upsetting me right now so I. Can't confirm, I'm going off memory... Lol

[EniGmA1987]

Yes I did. It is a VLSD differential from a G37s. I cant be absolutely sure, but I thought the physical size of the M45 rear differential and this one are different. I know they have different mounting bolt pattern and size to the mounts. In that thread from Ken he took a side by side picture of both diff's, so if someone can end up finding that thread then we can see if they are the same size or not

Stock M45 rear differential uses 3.29 ratio gears. The M35 both base and sport I believe use 3.54 ratio (cant remember for sure but I know it is different and less than the X model), and the M35x uses the same 3.69 ratio as the G's



EDIT: found the thread:
g37s-diff-comparo-for-m45-pics-t464801. ... ear%20diff


From the pics it looks like the rear differentials are in fact the same size, just the mounting flanges and bolt patterns are different.

[JoshTex]

So is it safe to say you can swap the ring and pinion from a g37 into our M's?

[DeanM45]

So is it safe to say you can swap the ring and pinion from a g37 into our M's?

It looks that way.

Now, does anyone else have a limited slip rear end in their M?

[mexillis]

There's that one guy who put in 4.08 gears, using the same method of ken's thread. The reason I believe traction control still kicks in while doing a brake stand is because cars nowadays with all their high tech stuff made it where any time brake and gas are applied at the same time the ecu will make the brakes over ride the gas. And OP we def have an open diff, try driving in the snow with our cars....you're better off walking.

[DeanM45]

Thanks Mex. OK, next time I'll pull the cover off and see what is what. Working around the RAS is going to be a PITA. I am really curious now. Going through a turn if it starts to slide I give it a bit more power and she snaps back into place. I can remember some fun times with open diffs--my first Supra was an open diff. Start sliding in a turn and try to over correct with steering alone---left, right, left, right, lol, car was all over the place.

Doing a brake stand I can understand the ECU kicking in. I wasn't using the brakes though--just flooring it off the line and then stability control sees a huge difference in rear wheel and front wheel speed and cuts power.

As for snow, I did a trip up to Mammoth and two to Wrightwood and while it was different, the car did OK, even with the "summer" tires.

[seymore4]

DEAN! I can confirm I definitely do NOT have an LSD in my 06 M45 sport. Really miss my OS Giken superlock from the G35 sometimes ;P

[DeanM45]

DEAN! I can confirm I definitely do NOT have an LSD in my 06 M45 sport. Really miss my OS Giken superlock from the G35 sometimes ;P

Well, I had plenty of the 75W90 fluid left so I went ahead and pulled the cover off this morning. Definitely a LSD. Mechanical, I can see the clutch packs. The RAS is REALLY a pain to work around. Had to use mirrors to see everything. Could not see any markings on the assembly so I have no idea where it came from. The gear set is roughly a 3.2 (counting the rotations of the tire for one rotation of the driveshaft).

[BabyKrutz]

I have an '05 G35 and am looking at getting an '06-'08 M45. I hear that traction control on the M45's is not completely able to turn off. Do you know if they have the same system as the G35's b/c I have plenty of fun w/ traction control off on the G's.

Thanks

[seymore4]

They have the same traction control, and you can still turn it off. Only difference it that you (most likely) have a VLSD in the G35, and the M45 has an open dif. Lots of one tire fire when you get on it

[mexillis]

Im not saying that Dean doesnt have a LSD but I have been able to pull two strips of burnt rubber with my open diff.

[DeanM45]

Im not saying that Dean doesnt have a LSD but I have been able to pull two strips of burnt rubber with my open diff.

Level ground, equal traction, straight line both tires spin regardless of diff.
Easiest way to tell is to jack up the rear of the car, put it in neutral and spin a tire. If the other tire spins in the same direction: LSD, if it spins in the opposite direction: open diff. Or just pull the cover off and look.