Switched to Amsoil SVG - Observations

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Vehicle is 2007 Mitsubishi Outlander which has 27000 KM (1 mile = 1.6 km). Read somewhere that it is a good idea to replace factory fluids early. We are not talking about engine oil here btw. Had a drain and fill on the following: 1. ATF - Drained about 4 litres and refilled with factory recommended J2 Diaqueen bought from dealership. 2. Transfer Case - Drained out factory sae 80? and pumped in 75w-90 SVG. 2. Rear Diff - Replaced factory sae90? with svg 75w-90. Good News: Could not believe the gunk on the transfer case magnet. Liquid was kinda greenish gray. There were metal particles on the magnet. I wasnt there to check on rear diff fluid but it probably was slightly better. This could have been attributed to runnin in 2WD mode during summer. Another side benefit was that I now know how to do all the above fluid changes. Its easy and since I already do my own oil changes, it means that only fluids that I dont know how to change will be coolant, brake and PS fluid. Bad News: Fuel consumption increased. Engine oil hasnt changed (still running ASM 0w20) and part of the ATF replaced was with stock ATF J2 which is the same. So, it leads me to believe that either TCase or RDiff seem to be protesting a little bit since engine is now revving slightly higher than it was before for same speed. Also, my IP shows clearly a drop in mileage. First day it was a whopping 20% drop. Later it slightly improved but I am positive that it hasnt gone back to original levels. Here is what AMSoil product guide has to say for my vehicle Standard Differential, Rear .....GL-5 Above -23°C......80W-90, 85W-90, 90 SAE 80W-90 Synthetic Gear Lube Severe Gear 75W-90 SAE 75W-90 Synthetic Gear Lube Standard Differential, Rear .....GL-5 -34 to -23°C......80W-90, 80W SAE 80W-90 Synthetic Gear Lube Severe Gear 75W-90 SAE 75W-90 Synthetic Gear Lube Standard Differential, Rear .....GL-5 Below -34°C......75W Transfer Case,.....GL-5 90 SAE 80W-90 Synthetic Gear Lube Severe Gear 75W-90 SAE 75W-90 Synthetic Gear Lube
 
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 Originally Posted By: Seth
...engine is now revving slightly higher than it was before for same speed...
Are you saying that something is slipping now? Otherwise how would the ratio change?
 
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 Originally Posted By: Seth
1. ATF - Drained about 4 litres and refilled with factory recommended J2 Diaqueen bought from dealership. 2. Transfer Case - Drained out factory sae 80? and pumped in 75w-90 SVG. 2. Rear Diff - Replaced factory sae90? with svg 75w-90. ......I wasnt there to check on rear diff fluid...... Bad News: Fuel consumption increased..... First day it was a whopping 20% drop....now revving slightly higher than it was before for same speed...
I highly doubt switching to synthetic gear oil caused a 20% drop in MPG. But let's look at some possibilities... 1) Old ATF and fluids were very thin and sheared back to 75% or less of their original viscosity. 2) Factory fluids weren't originally as thick as you are thinking, and new fluid is higher viscosity. 3) Not sure if your tranny is adaptive, but either it's trying the same shifting patterns with new fluids 4) AT was reset....and is in learning mode...note mention of higher revs.... 5) None of the above...I don't quite understand your comment about not being there. Was this done at the dealer/shop? Are you sure nothing was bumped or disconnected or even they used the supplied fluids?
 
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I'm going to take a guess here. I think your differential is operating at a much cooler temperature now than it was with the OEM fill. This has been documented by others that have switched to SVG and SVT. The operating temp is now lower, so the viscosity is now higher than before. This is offering you better protection for the diff, but at a cost. The OEM fill may or may not have been the spec'd SAE 90 GL5 that the manual calls for. If it was, it was some real garbage and you were wise to change it.
 

Seth

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 Originally Posted By: Pablo
I highly doubt switching to synthetic gear oil caused a 20% drop in MPG. But let's look at some possibilities... 1) Old ATF and fluids were very thin and sheared back to 75% or less of their original viscosity. 2) Factory fluids weren't originally as thick as you are thinking, and new fluid is higher viscosity. 3) Not sure if your tranny is adaptive, but either it's trying the same shifting patterns with new fluids 4) AT was reset....and is in learning mode...note mention of higher revs.... 5) None of the above...I don't quite understand your comment about not being there. Was this done at the dealer/shop? Are you sure nothing was bumped or disconnected or even they used the supplied fluids?
Shop changed the fluids while I was there watching and noting down the tools and sizes required. I stepped out for a little bit when the guy was draining the rear diff. By the time I came back he was pumping in the svg. Sorry for the confusion. Thanks for your comments. Could be that the fluids are now thicker and causing more energy to be spent. Could be anything. Nothing is wrong with it.
 

Seth

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 Originally Posted By: INDYMAC
I'm going to take a guess here. I think your differential is operating at a much cooler temperature now than it was with the OEM fill. This has been documented by others that have switched to SVG and SVT. The operating temp is now lower, so the viscosity is now higher than before. This is offering you better protection for the diff, but at a cost. The OEM fill may or may not have been the spec'd SAE 90 GL5 that the manual calls for. If it was, it was some real garbage and you were wise to change it.
I was thinking the same thing. Better protection comes with a small price. Now I think of how bad the magnet looked with the gunk and how clean it looked after wiping it off, I wish I had the gear oil changed sooner. I was too concerned about the engine oil while I ignored the gear oil. Oh well, 27k km is still very young so overall, I am happy.
 

Seth

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 Originally Posted By: yugrus
 Originally Posted By: Seth
...engine is now revving slightly higher than it was before for same speed...
Are you saying that something is slipping now? Otherwise how would the ratio change?
No nothing is slipping or making any noise. Resistance seems to have increased thats all. Not sure when it will thin out again. Dont like the idea of dumping more fuel in. Its not as free wheeling as before but that could be a good thing.
 
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My mpg's in all three of my vehicles just dropped about 10%. It's colder now. Winter fuel is also more common. Both can make mpg drop.
 

jbl

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I think biggest affect on fuel consumption is winter fuel. I have never seen an change in fuel consumption then changing viscosity of oil.
 

Seth

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Its okay now.. svg is now settled in. Mileage returned to normal. Ofcourse, it is the third day after change so it took couple days to settle in. I cant explain the physics and chemistry behind it. But whatever it was is gone now.
 
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I REALLY honestly wish I would've shot my rear diff with my IR gun to check the temp before I switched. I know for a fact though I drove home from work one night to drain the old out, put the drain pan under the diff (my toyota has drain and fill plugs on the diff no rear cover to pop off) I loosened the drain plug, the plug was TOO HOT to touch I hat to spin it off with the wrench, the fluid coming out that splashed on my wrist was VERY hot.. The whole rear diff housing was hot and painful to put your hands on for more than 5 seconds or so.. I drive over 50 miles each way to work. 80 mph, cruise control both ways. Now I can drive home, and can put both hands on the rear housing after the same drive and it's warm to the touch. Not uncomfortable at all...
 

JHZR2

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winter fuel, colder temperatures and tire pressure (have you checked it recently????) are likely the culprits. Many folks have shown that the fuel economy differences going from a 20 or 30wt oil to a 40-50 wt oil in their engine are minimal... 2-3% at most, and even that is lost in the noise. Thetiny difference in operating viscosity from a slightly cooler diff couldnt have more than the same amount of effect. Sounds to me like other issues are at fault... JMH
 

JHZR2

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 Originally Posted By: Seth
Its okay now.. svg is now settled in. Mileage returned to normal. Ofcourse, it is the third day after change so it took couple days to settle in. I cant explain the physics and chemistry behind it. But whatever it was is gone now.
It is the fact that you didnt go at least 5 tankfulls to determine a trend. One or a few data points are worthless, regardless. JMH
 
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I run 75-140 in a differential that spec's 80-90. The car's EPA mileage states 25 mpg. Cruising at 72-78 mph, I average just over 25 mpg during the past two months (13,000 miles for me), and my best mpg's are always during warm temps, my worst are always during cold temps. I think it is partly due to air density at those speeds increasing the CD.
 
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