Heads-up: Change your differential oil

[lovemycarM35]

I called My Infiniti dealler and 280.00 for 07 M35X wow I had the transmission done for 200.00 I'll need to fine another shop for the diff

[EniGmA1987]

Doesnt the X model has two differentials though that need to be changed? One for front wheels and one for rear? That would probably be why it is so expensive.

[thomasm35]

What size hex do the bolts require?

10mm hex!

[szh]

Doesnt the X model has two differentials though that need to be changed? One for front wheels and one for rear?

Correct.

That would probably be why it is so expensive.

Perhaps!

This is still an easy DYI.

Z

[dorlandm]

I too did both of my differentials this past weekend! The drain plug magnet was coated with gunk! Well worth doing the job. My car has 63,000 and I would assume it is the first time these fluids have been changed. It was very easy! The front was a little harder since the plastic under cover has to come off but then it is right there in front of you. I would strongly recommend a pump from the local auto parts store to pump the oil in and remember the back diff take 1.6 Quarts and the front takes .65 Quarts. The method of simply filling the thing until it runs out the filler plug is okay but if the car is jacked up and therefore at an angle not so much. Also it shows in the service manual that the level should be about 1/2" below the fill plug. Anyway, look to see how much comes out and you will see what I mean.

Mark

[mexillis]

did you guys purchase a new gasket for each drain/fill plug? If so how much was it and what type is it?

[szh]

The method of simply filling the thing until it runs out the filler plug is okay but if the car is jacked up and therefore at an angle not so much. Also it shows in the service manual that the level should be about 1/2" below the fill plug.

If you look at the FSM (link in my first post in this thread), you will see a diagram (on page FFD-9 in the file FFD.pdf for the 2008 M for example). This shows a "finger" reaching in to see if the gear oil is just at the fill hole level.

Hence the recommendation to fill till it just pours out of the fill hole. And, yes, being on level ground is best, but not critical since the fill plug is on the side of the differential as I recall - this would make the angle of the car not too much of an effect on the content. Of course, as long as you raise both front or both back wheels ... not just from one side!

Z

[cji4130]

did you guys purchase a new gasket for each drain/fill plug? If so how much was it and what type is it?

i also saw this in the service manual and was confused. i plan on performing this myself on my 06 m35x and noticed it indicates not to reuse the gaskets. what are the gaskets?! Where do i get new ones?

[szh]

Hmmm ... I have re-used this particular gasket without issues in the past. As I recall, it was not a crush copper washer (like the engine oil drain), so it should be okay to re-use. But I have not done this in a while, so it might be worth looking into.

If you prefer to change it, then you can either get it from the parts department at an Infiniti dealer or, better yet, order it from www.everythinginfiniti.com (call and ask for Joe Tsensky) - link is in sig in the first post I made in this thread.

Z

[finfinM45S]

Thanks for the informative post, I have not changed my diff oil in 96,000 miles, I have to look into that today

I dont know what I was doing, but my mechanic was like we need to change that.

[mexillis]

I just changed mine with some royal purple and when I was draining it, the fluid looked like new oil. It wasn't dark in any way even though enigma is right about trying to judge it by its color just wanted to share that little bit of info. Also i forgot about the gaskets not to re-use them and don't recall even seeing one on either plug. I did have a small collection of metal shavings but not enough to worry about. I was going to take pictures of the location for the plugs but my phone died. They aren't hard to find its the only 2 hex holes on the differential. One is in the middle when standing in the back facing the engine and one on the passenger side next to the half shaft. I also noticed smoother shifting on the way home and used to have a sorta firm shift from a low speed going to 3rd gear and that's gone.

edit just for mileage info, i bought the car with 48k did a transmission flush/fill at 60 and barely did the diff drain and fill at 82.5k

[loystock]

I change fluids every 2 years...and they are due in July this year. A pump will really help.

[shockwave20]

Going change mine next week

[TDot]

I think I'll give this a try. I didn't know what the differential was with everyone saying just look at the differential so I went searching on YouTube and found these great tutorial. The first one is a G series which hopefully all the plugs are the exact same on the M, The second is an entirely different type of vehicle that is much more detailed in cleaning. it will give you a great reference point along with szh's steps. I have no intention on paying $280. Has anyone else really cleaned out the differential like the second example?

http://youtu.be/mDdYuWkWjjg

http://youtu.be/KmqMUJb-E4M

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

[Blackzilla]

thanks for the vid TDot im going to attempt this here soon

[Blackzilla]

i know this is old but where did everyone get the gaskets? im trying to order them from everythinginfiniti.com but its almost $30 for just two gaskets

[gavnator]

I have an 06' M35X with 72000 on the clock. I had the Infiniti Dealer in Hartford, Connecticut change the oil in both differentials and transfer case at 42000. It cost $347.00. All labor. After reading this post, I called the service department at Roswell Infiniti ( I now live in GA) on this as I am going there in Sept. for an oil change. 2 different service advisors on 2 different occasions told me that my car is not due for this service until 90,000 miles. They said they do not necessary go by the service schedule but many times more on service/field experience. I will ask about this again when I go in for the oil change.

[szh]

My differential gear oil is changed out every 30k miles or so ... probably overkill, but it is simple and relatively inexpensive enough to do. Using Mobil 1 75W-90 Synthetic Gear Oil (the other weight of Mobil 1 75W-140 would probably be fine too).

Z