Good evening, recently I was changing my rear diff oil and I accidently used 80w-90 instead of 75w-90 due to my mistake in reading the owners manual wrong. As I moronically skimmed it and saw 80w-90 thinking to just go with it, without reading carefully that a 7A/T 2WD needs 75w-90 (I drive a 2013 Infiniti g37). I have driven the car around ~100 miles and having it immediately changed. I was wondering if this could cause any major damage or any immediate damage in using the wrong gear oil?

 

Don't overthink it and do not stress over it. That 5 point difference in viscosity is minor and virtually unnoticeable under normal driving conditions. I see no real need to change the gear oil again unless you routinely track the car or drive to Siberia, lol.

No harm, no foul.

 

The big deal is using a GL5 spec where GL4 is called for. Don't believe this applies to the rear end, but does apply to the MT gearbox.

 

Since the OP referenced the rear end at the start of this thread, I hope he used a GL5 spec lubricant for the diff. GL5 has pressure sensitive compounds that help protect the diff gears, but have a horrible sulfur-like smell. Don't ever put a GL5 lubricant in either a auto or manual tranny, however.

 

If this was a DIY, then I think you would just drain and fill again with the proper fluid.

However, if this involves shop time, and scheduling, and more money than just a couple quarts of 75W90 GL-5...

Either way, it would drive me nuts. I'd make the swap.

 

Hi guys, about the rear differential. If the car is on jack stands and wheels are off the ground, is this level for the diff fluid?
I notice the diff/ rear end is a lot lower than if you drove onto a ramp and lifted (like on an alignment machine), or even sitting on level ground.
If the car is on jack stands (and diff hangs low/ freely with no jack under it), do you: fill, leave fill open, lower car, let excess drip, lift, reinstall fill plug to 25 lb/ft, Done? Is there a way to 100% guarantee a perfect fill level? Will leaving a little extra in, hurt? I assume this procedure is identical across the entire Infiniti line-up and rwd Nissan?
What is the proper procedure? Is the diff still level in either position?

 

My idea of level was placing car on 4 drive on ramps by way of floor jack. Drain, refill until it leaks out.. Put plug back in once it stops dripping. Done.

75w90 vs 80w90... Eh... I wouldn't lose sleep over it. Anyways, you're in TX. It gets hot in TX.. very hot. If you were in chicago or MN, then I might be slightly concerned.

 

I backed my rear up a pair of ramps, while the front end ran up a pair of stacked 1x12 boards. Not exactly level, but it was either that or figure out a way to get all four corners up when I only have 2 jack stands.

 

Sorry for the very late reply, following update to my issue, so here's what happen after few days of putting the wrong diff fluid. Since 80w-90 gets pressurized differently than 75w-90 the fluid back flowed into the the rear diff vent and I lost 3/4 quarts of fluid. I took it to Caliber auto care (who explain this to me, highly recommend them for those living in Houston) and they switched the fluids for me for free. They said my diff suffered little to no damage, a least seen by them. And I had no problems since. To answer dkmura question, yes I used GL5. And for SlimTV it was not level for me, I took my car off jack stands and a bunch more fluid came out (if your lazy I recommend to get a air pump 10$ from AutoZone and just pump out as much as you can on bottom of the diff)

 

The diff isn't part of the suspension like it is on a live axle vehicle. Its bolted to the subframe. It doesn't drop down when you lift the car.

Just make sure the car is level on 4 jack stands. Obviously on a level surface.

Huh?

The 80W just describes the oil's viscosity at low temps.

You sure you filled the diff correctly? Sounds like you did it with only 2 wheels off the ground or something?

 

Huh is right. IMO 80w90 is nearly identical to 75w90. Sounds like you (they?) overfilled it to begin with.

 

Feel bad bringing back a old thread, but does anyone know if the vlsd in a 6mt needs 75w-90 or 80w-90? With Midwest wintering winters and summering summers, not sure which one would be needed. The FSM for 2011's states 7A/T 2wd for 75w-90 and everything else uses 80w-90 but I see people put 75w-90 in their vlsd all the time. Very worried

 

I've got the 6MT with VLSD, and I live in Western NY. Back when I did this fluid swap, I used 2 quarts of Redline 75W90 GL-5.

 

Awesome good to know. My worry came from this stating that 75w-90 comes from the FSM stating it's only for 7AT 2WD vehicles ↓↓

 

Hmm. That sure is confusing.

Maybe hop on the the Z boards for an answer. There's a lot more 6MT Z's than there are G's.

If you come up with a solid answer, let me know.