I spoke with a Mobil 1 rep about changing gear oil in my 2005 G35X. I wanted to use Mobil 1 API 5 75-90 gear oil but the rep said that I shouldn't mix brands. If I couldn't get all of the old gear oil out "... don't mix brands." I tend to believe him because I am sure he wants to sell his product.
Questions: Do you keep to the OEM brand? Shouldn't all popular brands of gear oils (regular oil, not synthetic) be similar and mixable? Doesn't all the oil drain out so that the gear oil really isn't mixing?
Last question on gear oil: Does anyone know where to purchase a gear oil pump for qt bottles on line?
CliffordS

 

Stick with same company name don't mix castrol with mobil or vise versa...

 

MOST of it drains out. Like everything there will always be a small trace, i ran mobil 1 oil just because its there and easy to get. I'm going with redline next time.


As for the pump, you can get a pump from walmart in the area of $5, its orange/red with a actual hand pump, it works. Not as great as a $20 bottle pump but for $5 plus your only doing it every 30k.

I wouldn't worry if your draining and filling, I was thinking in terms of 1qt mobil and .5 of Nissan is something i wont mix.

 

Thanks, I'll order 2 qt's of Redline. I notice that my 2005 G35X service manual doesn't give a millage figure for changing the differential gear oil. Did I miss it?
CliffordS

 

FSM shows you should inspect every 15K miles and change when necessary. 30K service intervals are when the dealership normally will change the diff fluid.

 

clif, you do realize you have more then 1 diff to change right?

AWD have front and rear diffs that can run 75-90 and then you have a transfer case and transmission to flush as well. I'm not sure what kind of interval i want to do all this stuff at. I'm not doing them every 15k. But all those at 30k sounds about right for me.

 

With redline it is best to stick with 75-85, mix MT90 and MTL 50/50.

 

Wrong, I should have realized that the X had two differentials. I assume that I have to drop the bottom cover-shield to get to the front differential. Are the plugs on the front differential hard to get to?
CliffordS

 

all the plugs are realiatively easy the reach. with a normal hex socket and a 3/8 ratchet. Some are extra tight and might require a breaker bar to get it loose but thats about it.

Yes the front diff is under the sheild, if you want to search i think a guy name mikee2 or mikkee2 post pictures of all the locations of all the plugs.

 

Thanks,that's all the info I need. I'll be able to do it.
CliffordS