Transfer case fluid

[samc]

We all know that the 06+ transfer cases use 80w-90 oils. But I've been searching and this came up.

Is there really that much of a difference or am I just overthinking it for no reason? They both meet the API Service GL-5 rating.

Valvoline/1 qt. 80W-90 Durablend synthetic gear oil
Valvoline/1 qt. 80W-90 Durablend synthetic gear oil (280) | | AutoZone.com

Or just stick to good old mobil1?
Mobil/1 qt. 75W-90 synthetic gear oil
Mobil/1 qt. 75W-90 synthetic gear oil (98W573) | Gear Oil | AutoZone.com



EDIT ~~~~~~~~~~~~~~~~~~
And so I finally got around to doing it, I bought 75w-90 Mobil 1 Transfer Fluid and this funnel type tube thing that attaches to the bottle.
First off the bolts were on tight as hell, certainly way above 33 ft-lbs as stated. But both used 20mm washers, although mine looked brand new (no indentations) so I would be confident in reusing them. A few tips, use a breaker bar and a small 3/8" extension. And I replaced just about half of a one liter bottle, I kept going into it started to overflow.

And by all means get a handpump such as this, it'll say you time and aggravation.

[rocky]

You have to be very sensitive to your vehicle's noises, transmission drag etc to notice any difference between synthetic and dino 90wt.

[samc]

Well yes I know the first one is a synthetic blend. But I'm more curious to the 75w vs 80w. What's the differences between both? Is it similar in the way for engine oil, where the first number shows the viscosity at 32 F temp? If so (without researching) I would think the slightly lower weight of 75w-90 would be better overall vs the 80w weight.

Either way I'm leaning towards the mobil1 simply because I use the same for engine oil.

[RSQ Pilot]

Originally Posted by samc

Well yes I know the first one is a synthetic blend. But I'm more curious to the 75w vs 80w. What's the differences between both? Is it similar in the way for engine oil, where the first number shows the viscosity at 32 F temp? If so (without researching) I would think the slightly lower weight of 75w-90 would be better overall vs the 80w weight.

Either way I'm leaning towards the mobil1 simply because I use the same for engine oil.

Pour Point:
1st -32.8f valvoline durablend
2nd -50f M-1 Syn
or
-49 valvoline 75W90 Synpower

[RegDunlop]

so can you use a 75w-90 or does it have to be an 80w-90????


does anybody have this answer?

[A6Pilot]

I've used Mobil 1 75w-90 for 7 years. No issues, except transfer case temp runs much cooler. From the literature from Mobil 1, the synthetic gear lube will run cooler, because of inherent film strength and lower friction lubrication properties of synthetic oils.

Mobil 1 Synthetic Gear Lubricant LS 75W-90

[samc]

Ok Mobil1 it is for me, will buy a bottle tomorrow. Father's day transfer case fluid change?....

Either way what suckion or hand pump did you guys use? I know the transfer case is on the mid-bottom of the pilot and so there isn't much leverage to pour the bottle down.

[A6Pilot]

A 3/8" square drive long handle breaker bar will fit in both the drain and refill plugs. I use a 1/2" breaker bar fitted with a 1/2" to 3/8" socket adapter. Remember to remove the fill plug first. That way, if you can't remove that plug, you haven't drained the transfer case, with no way to replace the case fluid. The first time I removed the plugs, it took considerable effort to break them free.

The transfer case only has a capacity of .46 qts, and I just slip on a plastic tube over the fill "spout" of the Mobil I 75w-80 gear oil container, and squeeze the plastic container 'till the case is full. It's a tight fit, but the tube works pretty well, and I don't need a fill pump to refill.

To complete the job, remember to use new 20 mm crush washers (my dealer gave me a handful awhile back), and torque the plugs to 33 ft-lbs.

I've drained the fluid 4 times, and each time the drained fluid looks brand new. I'm thinking I might extend the drain interval next time.

[samc]

75w-80? But thanks for the tip, I didn't get around to changing the fluid because I couldn't find the washers or a pump locally.

[RegDunlop]

Thanks A-6, when I do get around to changing it I will use the M1 75w-90.

I have no idea if it was ever done before, despite the fact I am the original owner and I always took it in to the dealer for maintenance.

I was busier then, when I became less busy I decided to do all the maintenance myself , and going back through the dealer records it is VERY unclear what they did/did NOT do....things like at the 30k , the ATF should have been drained and filled, but I don't think it was....when I confronted the service writer about this at my last visit, he said I needed it done as it never was done...then when I asked him what the **** did I pay 350 for at the 30k check he said oh yeah it was probably done then.....

I hate the ****ING DEALERSHIP...

[samc]

So I finally did the fluid change, my thoughts edited on the first post above.