Rear dif. fluid? (2003 Infiniti M45 ... but applies to other model years too!)

[caug1]

hello,

i have 03 m45 and would like to change rear dif. fluid. I was thinking of "motul" very , very good stuff, but not sure if they make the right one. we need 80w90 lim. slip is that correct?

what would you recommend?p.s.how many qt.s i would need to get?

http://www.ltbmotorsports.com/90palidi2l.html

thanks an advance,

caug

[DRIPS]

i highly recommend just using what they have at the dealership. It is easy to complete the change urself if you want but generally u should not change fluid types.

[caug1]

i tolked to to defferent people at the dealer and got two different type, 75w90 and 80w90 limited slip. also told me that they put what ever is cheaper type.I was like WTF IS UP.if somebody know the differense , please let me know.also want syntetic stuff only. unless of course.thanks.

[szh]

The Infiniti manual calls for 80W-90 as I recall (this is in the basic spec here sticky here too or the M service manual - see link in the stickies!). However, you can easily use 75W-90 and the wider-range 75W-140 without any problems at all.

I strongly recommend using the Mobil 1 Synthetic gear oil for this purpose - either the 75W-90 or the 75W-140! And, I would also do this change every 30k miles at the very least.

By the way, this is a relatively easy DIY if you can raise the car on a lift or can reach the two plugs and openings on the differential. I would strongly recommend making sure you can open the fill plug first, before you actually open the drain plug ... just in case you have difficulty with reaching or opening the fill plug!

After opening the drain, once all the old oil is gone, close the drain plug, torque it to the correct spec (23-28 ft-lb), and put in enough gear oil into the fill plug till the oil just starts to pour out of the fill plug. Then close that fill plug to the correct torque (23-28 ft-lb).

The differential capacity is 3 U.S. pints. Means you have to buy two 1 qt bottles.

Note that it is a bit tricky to tilt the gear oil bottles to put the oil into the fill plug - particularly if you do not raise the car ... might have to get another smaller, clean container, with a bendable spout or something, to do the job.

Z

[szh]

i highly recommend just using what they have at the dealership. It is easy to complete the change urself if you want but generally u should not change fluid types.

Ummm ... there is no problem with mixing a bit. If you drain the differential gear oil completely, and then refill with a synthetic gear oil, that should be just fine!

Z

[caug1]

Thanks for the info.Do i need to look for one with 75w90 "lim. slip" sign or 75w90 only?Thanks again,Caug.

[szh]

Thanks for the info.Do i need to look for one with 75w90 "lim. slip" sign or 75w90 only?Thanks again,Caug.

Both of the Mobil 1 Synthetic 75W-90 and 75-140 contain limited slip additives already. You probably do not need to add any extra such additive, although Mobil 1 does say that you can do so, if you want ... but I am not sure what additive to use in this case.

BTW, I suspect that other manufacturers synthetic gear oil is probably comparable to the Mobil 1. As long as you use something good and API GL-5 spec'ed, you are going to be fine!

Z

[maxnix]

Thanks for the info.Do i need to look for one with 75w90 "lim. slip" sign or 75w90 only?

Probaly not. While the pre 2002 had VLSD, the altter V8 employ an open differential.

[Da Dark Jedi]

Use Amsoil Severe Gear oil in 75W-90, 75W-110 or 75W-140. Performs better than Mobil.

[szh]

Use Amsoil Severe Gear oil in 75W-90, 75W-110 or 75W-140. Performs better than Mobil.

Okay, but more out of curiosity than anything else: do you have any test results or site link that documents this difference in performance?

The reason I ask is that, in most cases, differential gear oil is not as big a deal as engine oil (that see far more heat, etc.). So, once you pick a good synthetic gear oil and it has LSD additives, anything more is probably much overkill - again, if you have test results to the contrary, I'd love to read them!

Since Mobil 1 Synthetic gear oil is more generally available at typical auto parts stores than Amsoil, I'd use it without hesitation if that was all that the store (that I went to) had in stock. Of course, if you still want to use Amsoil, and find it easily enough, then that is fine too.

Z

[caug1]

Sounds good both ways, with the prices on gas i will to take it easy for now, plus i am not in florida doing 1/4 pull every day.

i wnder if my car has a probler. let me know if you all have the same problem.Who knows why only one tire spins of the line on my car when floored ?does new m has the same problem too?if 03,04 m had better set up to hoop up rear tires of the line, we would do better at the 1/4mile times. wouldnt you think so?please let me know.thanks,caug.

[chitownm45]

I have a 2003 M45, coming up on 170k miles. I take my car into service regularly for preventive maintenance, and it was never mentioned that I would need to change my differential fluid. I love my car very much and want to make it right.

After reviewing the forums, I thought changing it with Moble 1 75W-90 or 75W-140 is the best option. I noticed that the 140 is double the price of the 90, what's the difference between the two? What would you do if in my position?

Thanks in advance for any feedback.

[Towncivilian]

Use 75W-90, 75W-140 is excessively thick at operating temperature and not specified as suitable in the factory service manual. If you live by an Advance Auto Parts, order the fluid online and use discount codes, then pick-up in store to save some cash. I'd suggest a fluid pump (search for W1139 on the AAP site) to help fill the diff as well.

Welcome to NICO.

[chitownm45]

Thanks for your input I appreciate it.

Very excited to be apart of NICO seems like an awesome forum!