How To: Reduction Gear Oil Change

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Learjet said:
I'll bet there is nothing wrong with that fluid :D

I am curious myself if it has anything about it that would be "bad" for the gears, but I am not a expert in fluid dynamics, so it would be best to post up the results here (or the elsewhere should it be a better area) for someone that does know about it to tell us if it's good or bad or neither. :?
 
How about we let Blackstone labs decide?
I'm thinking 70,000 is probably close to being "bad". I doubt they will say "oh you could have left that in for another 70,000 miles.
And I bet 20,000 to 25,000 miles will be fine.
 
Oilpan4 said:
How about we let Blackstone labs decide?
I'm thinking 70,000 is probably close to being "bad". I doubt they will say "oh you could have left that in for another 70,000 miles.
And I bet 20,000 to 25,000 miles will be fine.

I've never used them, so I didn't know if they just give you technical stats or if they give you a cool summary like "oh this is bad, this is tearing up your gears", etc. :mrgreen:
 
knightmb said:
I've never used them, so I didn't know if they just give you technical stats or if they give you a cool summary like "oh this is bad, this is tearing up your gears", etc. :mrgreen:

I've used Blackstone Labs for motor oil test. They'll give you an English description of the results. Often, it comes down to, "This oil change interval try going an additional 1,000 miles." There are statistics for the test measures that will show universal values and your past values.
 
The kit just arrived in the mail, time to send it out! :mrgreen:
KZzSxzP.jpg
 
HRTKD said:
knightmb said:
I've never used them, so I didn't know if they just give you technical stats or if they give you a cool summary like "oh this is bad, this is tearing up your gears", etc. :mrgreen:

I've used Blackstone Labs for motor oil test. They'll give you an English description of the results. Often, it comes down to, "This oil change interval try going an additional 1,000 miles." There are statistics for the test measures that will show universal values and your past values.

I used them for a few years. Never anything particularly interesting in the results which is a good thing of course. I know the tests can alert you to problems before they become big problems, but in the end it was too much hassle for me. Modern ICE engine oil is fantastic and the question of "which oil" is more for entertainment than practicality. Change it regularly and oil analysis is kind of a waste of time, imho.

I think the service is probably a lot more useful for fleet or industrial applications trying to optimize maintenance intervals and avoid downtime. Or perhaps individuals who really push their equipment (tuners, racers, hot-rodders). For me, cars usually last a long time anyway so I saw little marginal value.

That being said I am curious as to how well this "lifetime fluid" is doing at 67K ;)
 
Nubo said:
I used them for a few years. Never anything particularly interesting in the results which is a good thing of course. I know the tests can alert you to problems before they become big problems, but in the end it was too much hassle for me. Modern ICE engine oil is fantastic and the question of "which oil" is more for entertainment than practicality. Change it regularly and oil analysis is kind of a waste of time, imho.

I think the service is probably a lot more useful for fleet or industrial applications trying to optimize maintenance intervals and avoid downtime. Or perhaps individuals who really push their equipment (tuners, racers, hot-rodders). For me, cars usually last a long time anyway so I saw little marginal value.

That being said I am curious as to how well this "lifetime fluid" is doing at 67K ;)

When I had my Titan, I used Blackstone. They kept increasing my interval, until I went too far one time (my fault). Otherwise, nothing interesting. I haven't tested any of the oil coming out of my F-350.
 
I never sent them an oil sample from a transmission, gear box, differential, ect. Always from an ICE.
 
knightmb said:
The report is here :mrgreen:
I bet they haven't seen many of those.
So the oil is about done after 50,000 to 60,000
miles.
PM me your paypal and I'll send you $20.
Then I'll do mine around 25,000 miles and I'm sure it will be good.
I'm almost to 20,000 now, I'll be at 25,000 early next year.
 
This data may support the first change at 5K miles. Nissan changed all gear boxes fluids after first 600 miles on my new 1973 B-110.
 
Considering that many manufacturers are setting the oil change interval on transmissions to more than 100,000 miles, the oil that Nissan put in the gearbox doesn't seem to be high quality. Medium quality at best.

I understand this isn't a transmission that has a cooler and filter. But even transfer cases are rated for a lot of miles before a change is scheduled.
 
knightmb said:
The report is here :mrgreen:

I do give credit to Blackstone for having a real person look at and analyze about the test results. Or at least it seems that way. If not I don't want to know. :lol:
 
Nubo said:
I do give credit to Blackstone for having a real person look at and analyze about the test results. Or at least it seems that way. If not I don't want to know. :lol:

All my reports from Blackstone were custom. The one where I forgot to change the oil on time was kind of funny. It started with, "You went too far."
 
Knightmb & olipan4 thanks for posting, good info. I'm glad I changed mine at 34k and 7 yrs old . Went with synthetic for less friction and better range . Still waiting on that range thing.
 
Steelcity said:
Knightmb & olipan4 thanks for posting, good info. I'm glad I changed mine at 34k and 7 yrs old . Went with synthetic for less friction and better range . Still waiting on that range thing.

If I am reading my report correctly, my old oil viscosity is much higher than the new stuff I replaced it with, especially given the temperature difference that the old stuff needed to be heated near the boiling point of water to be within the "recommended" range. The new stuff remains low even when not heated. I suspect that the gears in the Leaf will never reach the boiling point of water since it is not in an ICE engine, so anyone that does a replacement, make sure you get fully synesthetic that has a low viscosity even at low temperatures. The viscosity of my old oil at over 200F was 44, the new stuff I replaced it with is 5.91 at over 200F, 28.82 at 100F, so even cooler still has better viscosity than my old stuff. I suspect that is where I see the slight improvement in my range, which continues now that it has gotten much cooler outside. I haven't seen 80+ miles on the guess-o-meter in years. My actual real-world test of how much can I run it down to, I'm still getting +70 miles per charge when I use to only get lucky if I got 60 miles per charge.

ac4CzOq.jpg
 
knightmb said:
If I am reading my report correctly, my old oil viscosity is much higher than the new stuff I replaced it with, especially given the temperature difference that the old stuff needed to be heated near the boiling point of water to be within the "recommended" range. ...

The two viscosity readings of the old fluid on the report were essentially at the same temperature (100c vs 210F) ; they're just two different ways of measuring.

Table_5_viscosity_comparison_chart.jpg
 
knightmb said:
Steelcity said:
Knightmb & olipan4 thanks for posting, good info. I'm glad I changed mine at 34k and 7 yrs old . Went with synthetic for less friction and better range . Still waiting on that range thing.

If I am reading my report correctly, my old oil viscosity is much higher than the new stuff I replaced it with, especially given the temperature difference that the old stuff needed to be heated near the boiling point of water to be within the "recommended" range. The new stuff remains low even when not heated. I suspect that the gears in the Leaf will never reach the boiling point of water since it is not in an ICE engine, so anyone that does a replacement, make sure you get fully synesthetic that has a low viscosity even at low temperatures. The viscosity of my old oil at over 200F was 44, the new stuff I replaced it with is 5.91 at over 200F, 28.82 at 100F, so even cooler still has better viscosity than my old stuff. I suspect that is where I see the slight improvement in my range, which continues now that it has gotten much cooler outside. I haven't seen 80+ miles on the guess-o-meter in years. My actual real-world test of how much can I run it down to, I'm still getting +70 miles per charge when I use to only get lucky if I got 60 miles per charge.

ac4CzOq.jpg

Where the gear teeth touch and metal to metal contact is made under heavy load the surface of the gears may reach 800 to 1,000F. That's the activation temperature of the ZDDP anti wear additive. When the heat and pressure breaks down the ZDDP it coats the gear teeth with zinc and protects the metal underneath. It's nano technology from the 1930s.
Too much heat and pressure blows right through the zinc coating, not enough heat and pressure and the ZDDP never activates.
 
I'll be doing this oil change soon, and as I was looking the area over I saw what looks like a third drain plug:

PaWlss3.jpg


It's a bit left/below center in that picture, somewhat illuminated, at the top of the same housing that the other two plugs thread into.

I guess 'fill plug' would be a better term, assuming it goes to the same space as the other two plugs go to.

Before I open that one up and have a look, can anyone confirm or deny my hypothesis? It will be a lot easier to fill this gearbox back up with a vertically-oriented opening.

(But starting to doubt that this is the case as the service manual would surely use this one if it were an option.)
 
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