Heads-up: Change your differential oil

[thomasm35]

I changed the differential oil in my 2007 M35 for the second time at 60K and it was very dirty.When I changed it at 32K ,when I bought the car, it was filthy - I thought it was the driving habits of the previous owner who drove the hills of San Francisco. Not sure why it gets so dirty - this is not the experience I had with other cars.

[cruzad3r]

rear diff? wat fluid are u using?

[mgokool]

I'm also interested as to what type of fluid you're using as I'm about to change mine pretty soon! Thanks!

[bbs350z]

dirty open diffs!!! i would switch to a full synthetic blend. i had motul in my z and evo and loved it

[szh]

I use Mobil-1 Synthetic Gear Oil 75W-90 ... every 30k miles! You need two 1qt bottles (non X models). Easy DIY actually.

Another good one (commonly available some places) is Mobil 1 Synthetic Gear Oil 75W-140.

Z

[cruzad3r]

i used motul on my TT as well. don't remember the exact grade, i think it's 75-90w but i can double check. i actually use the same fluid for my transmission and rear diff for as long as i've owned the car.

i'm interested in other people's choice of fluid and tips on what to expect with this job. thanks folks

[WhoDey456]

How about a how to on this as I am approaching my 60k service and would like to save some money with DIY!

[LoveMyM35]

+1 on that how to mine was done at 30K I'm at 60K know I need to get this done is the dealer to much $

[EniGmA1987]

+2 on the how to. If it really is easy I would love to save a couple hundred bucks doing it myself

[cruzad3r]

so from prior experience i believe there are two important steps. 1) open the fill plug to make sure you have a way to refill your fluid in case "something" happen and 2) open the drain plug to get rid of the old oil.

now the question is - where are the drain and fill plugs so people who have done this before, please post that with a picture of your car and tell us what's the hex size bit you're using for these plugs. i'm assuming 19mm hex size?

[thomasm35]

The manual for the 2007 M35 calls for SAE 80W-90 gear oil. I used Valvoline synthetic blend 80W-90; you have to buy 2 quarts, the 2007 m35 uses 1.5 - 1.6 quarts for the refill. I couldn't find any Mobil1 with the correct viscosity, the closest was 75W-90 and I chose to stay with the manufactures recomandation.

Changing this fluid is easy - you just have to remove two bolts(remove the fill bolt first).

When I saw how dirty the gear oil was in my M35 I changed the differential oil in my Lexus LS460(45k miles). It was so clean that I felt foolish for replacing it. Can't figure why the Ms is so dirty!

[a.blanco0905]

Can't figure why the Ms is so dirty!

Thanks for all the input Thomas!!! Is your M35 sport? and does the M35 sport have rear active steering like the M45 Sport? If so that could be the reason.

i used motul on my TT as well. don't remember the exact grade, i think it's 75-90w but i can double check. i actually use the same fluid for my transmission and rear diff for as long as i've owned the car.

i'm interested in other people's choice of fluid and tips on what to expect with this job. thanks folks

At least you dont have to buy Haldex fluid from Audi for the diff.

[thomasm35]

It's not a sport nor does it have rear active steering.

[cruzad3r]

The manual for the 2007 M35 calls for SAE 80W-90 gear oil. I used Valvoline synthetic blend 80W-90; you have to buy 2 quarts, the 2007 m35 uses 1.5 - 1.6 quarts for the refill. I couldn't find any Mobil1 with the correct viscosity, the closest was 75W-90 and I chose to stay with the manufactures recomandation.

Changing this fluid is easy - you just have to remove two bolts(remove the fill bolt first).
!

- so for slow people like me, i would like to see the pix of those plugs eheheh

At least you dont have to buy Haldex fluid from Audi for the diff.

oooh but you're wrong ... the haldex AWD system fluid isn't expensive; it's the dam filter that is a PITA to remove. i still have them in my garage for spring tuning

[relentless1]

Weather permitting, I'm planning on doing mine this weekend. My local shop doesn't have Mobil 1 Gear Oil so the guy recommended Castrol - SYNTEC Full Synthetic Gear Oil, 75W90. Hopefully Castrol is ok.


Would it be similar to this, which is on an G35? http://www.wonderhowto.com/how-to-chang ... 3057/view/

[Double E]

Good info here. How about Y34...what's the fill amount?

[szh]

My local shop doesn't have Mobil 1 Gear Oil so the guy recommended Castrol - SYNTEC Full Synthetic Gear Oil, 75W90. Hopefully Castrol is ok.

Should be fine.

Would it be similar to this, which is on an G35? http://www.wonderhowto.com/how-to-chang ... 3057/view/

Pretty much.

Changing differential oil method is virtually identical on all Nissan and Infiniti's ... probably on all standard cars.

Z

[szh]

Good info here. How about Y34...what's the fill amount?

On Y34 too, it is more than 1 qt, so you have to buy two 1qt bottles.

Simple instructions - just make sure that you have a small, clean funnel with a flexible rubber hose, or one of those squeeze handle pump bottles with a flexible hose.

0. Lift the car up keeping it reasonably level ... using a lift is safest, but not everybody has access to one. Never do this work on just your jack from the trunk. Using jack-stands in addition to the jack itself, is the absolute minimum, and essential for safety.
1. Open the fill entry bolt first - making sure you can get it off to avoid any potential problems with it later! Don't lose the washer.
2. Open the drain bolt and let the old gear oil drain out thoroughly. Don't lose the washer.
4. Clean the drain bolt and put it back on and tighten. Follow the torque specs (in our M manual section here).
5. Use the funnel and/or pump bottle to fill the differential with fresh 75W-90 gear oil all the way to the fill hole - you will need more than 1 qt to do this.
6. When the oil is filled to the level of the entry, put the entry bolt back on and tighten to the correct torque.
7. Lower car.

One of the easier DIY things to do on our car.

Also, remember that the X (AWD) models have more than one differential - since I have not done one of those, I am not sure of the exact procedure and whether it is more complicated or what the fluid spec is. The detailed service manuals here at NICO should give you the details.

Z

[cruzad3r]

so no one want to post the picture of those two plugs?

[szh]

so no one want to post the picture of those two plugs?

It is in that video ... link above.

And, if you go to the Service Manuals (link in my sig) and open up the http://www.nicoclub.com/FSM/M/2006_M45-M35/rfd.pdf file (for the 2006+ M), you will see a diagram - this diagram has arrows showing the location of the bolts on the differential.

Plus, you can't really miss them! Look under your car at the differential and they will be fairly easy to find!

Also, please don't forget that your X model has more than one differential ... you may need to look at the http://www.nicoclub.com/FSM/M/2006_M45-M35/ffd.pdf file too! And, you will need 3 qts of fluid (it is actually just over 2.3 qts ... so you have to get one extra bottle).

Z

[06M4.5]

what is the dealer charging for this?

[cruzad3r]

your first born son LOL

probably in the neighborhood of 150 and up.


and thank you Z for posting that up once i change the fluid, i shall post a how-to with actual pictures LOL ehehh

[EniGmA1987]

I think my dealer charged $200 for this. Of course I didnt get it done there, I got a whole different rear diff and new oil in that.

[lovemycarM35]

The deal over charges for everything oil change at my Infiniti dealer is 50.00 bucks

[EniGmA1987]

Is that really a lot? Costs me $30 to do it myself with a good filter and good oil, and I get a free car wash and inspection from the dealer. And free cookies and coffee.

[relentless1]

Just to follow up, I had mine done this past weekend and I can tell the car accelerates much smoother. I thought it was placebo but my mechanic friend noticed it too. Plus I had the engine oil switched to fully synthetic as well so that probably contributed to it.

The rear diff oil was the darkest I've ever seen oil! I was surprised to see closed case oil be that dirty. For the cost of the oil and labor involved, this is definitely worth changing every year.

[cruzad3r]

just to be clear - judging oil by its color is not the "greatest" thing you should do. you should send sample oil out to a lab for detail analysis if you wish to know its condition - basically to see if there's any metal shaving and such.

however i agree with everyone since it's relatively easy and cheap to change these oil, you should do it often. even when bringing it to the dealer, from what people posted, it's not that expensive neither.

[Ilya]

It's $230 for the 'four wheel service'. That's with fluid and labor. I have an X model.

The transmission service alone is another $220 or something.

I'm dropping my car off at the dealer tonight.

[thomasm35]

just to be clear - judging oil by its color is not the "greatest" thing you should do. you should send sample oil out to a lab for detail analysis if you wish to know its condition - basically to see if there's any metal shaving and such.

however i agree with everyone since it's relatively easy and cheap to change these oil, you should do it often. even when bringing it to the dealer, from what people posted, it's not that expensive neither.

The differential drain plug is magnetic and it catches metal shavings - I had a small amount of gup attached to it. I think next time I will change it after 15K and see what it looks like.

[SIK L]

What size hex do the bolts require?