Nitro Gear 4.56 ReGear - Why the different Gear Oil??? - Toyota 4Runner Forum

007Tacoma · 01-18-2021, 12:54 PM

I have searched, and I have asked in another thread... I feel like this needs its own thread because I can't be the only one with this question...

Quote:

Toyota Differentials (OEM) run LT 75W-85 GL-5 Gear Oil

Nitro Gears recommends using 80W-140 Gear Oil.

So, I am curious...

Why the difference?

What is the risk of running the lighter oil with the Nitro Gears?

If you have regeared, what oil brand and weight are you using???

Background information: I have 165,000 miles on my original 3.73 gears with heavy loads and tons of towing. I had zero metal flakes on the drain at 75,000 miles and 150,000 miles. Last month, I upgraded to a Nitro Gears 4.56 gear set. I did the initial break in then drained and refilled with 80W-140 with the expected fine metal shavings a decent looking oil. I refilled it with Castrol 80W-140 per my mechanic's advice. Since then have put 2,500 miles on the vehicle, and I'm about to change the oil again just to ensure everything is okay. I have noticed that my fuel economy is way down. Power is up, but but I can't break 13MPG unloaded cruising at 55 MPH (I was as high as 18MPG fully loaded - not towing).

rdruss · 01-18-2021, 01:32 PM

Quote:

Originally Posted by 007Tacoma

I have searched, and I have asked in another thread... I feel like this needs its own thread because I can't be the only one with this question...

So, I am curious...

Why the difference?

What is the risk of running the lighter oil with the Nitro Gears?

If you have regeared, what oil brand and weight are you using???

Background information: I have 165,000 miles on my original 3.73 gears with heavy loads and tons of towing. I had zero metal flakes on the drain at 75,000 miles and 150,000 miles. Last month, I upgraded to a Nitro Gears 4.56 gear set. I did the initial break in then drained and refilled with 80W-140 with the expected fine metal shavings a decent looking oil. I refilled it with Castrol 80W-140 per my mechanic's advice. Since then have put 2,500 miles on the vehicle, and I'm about to change the oil again just to ensure everything is okay. I have noticed that my fuel economy is way down. Power is up, but but I can't break 13MPG unloaded cruising at 55 MPH (I was as high as 18MPG fully loaded - not towing).

They are speaking from their experience and also advising you that if you have a problem and don't follow their advice don't be surprised if warranty denied.

Nobody Special · 01-18-2021, 08:37 PM

4.56 put more power to the ground.
More power, more pressure etc...
A lighter oil won't protect as well, (but don't mention that to people who swear by 0W20, even though they are two different applications).

007Tacoma · 01-18-2021, 10:01 PM

Quote:

Originally Posted by rdruss

They are speaking from their experience and also advising you that if you have a problem and don't follow their advice don't be surprised if warranty denied.

That doesn't explain the difference though...

My 3.73 gears looked great after years of heavy abuse with OEM gear oil (changed every 75K).

007Tacoma · 01-18-2021, 10:05 PM

Quote:

Originally Posted by Nobody Special

4.56 put more power to the ground.
More power, more pressure etc...
A lighter oil won't protect as well, (but don't mention that to people who swear by 0W20, even though they are two different applications).

Technically, they are not putting more power to the ground. The ratio is different giving more turns of the pinion gear (input from the drivetrain) allowing the engine to spin at a higher rpm to exert the same amount of force. The pressure is actually lesser on the gears (all other things being equal), they are just having to turn faster.

spartacus · 01-18-2021, 10:23 PM

Quote:

Originally Posted by 007Tacoma

Technically, they are not putting more power to the ground. The ratio is different giving more turns of the pinion gear (input from the drivetrain) allowing the engine to spin at a higher rpm to exert the same amount of force. The pressure is actually lesser on the gears (all other things being equal), they are just having to turn faster.

You'are dead on. The one negative of regearing. Higher rpms equal less gas milage. What size tires are you running?