View Poll Results: necessary to change differential oil?
yes
109
87.90%
no
15
12.10%
Voters: 124. You may not vote on this poll
Is it really necessary to change differential oil?
03-16-08 | 06:52 AM
#46
Lexus Fanatic
Joined: Aug 2004
Posts: 6,947
Likes: 4
From: Florida
Last edited by chuckb; 03-16-08 at 06:56 AM.
03-16-08 | 09:08 AM
#49
Well, technically you can get more power and gas mileage from changing the fluids. But, you're actually recovering lost power rather than getting more power. It's actually possible to gain a little more power by switching to synthetic, but that's a whole nother discussion 
Anyways back on topic. For example, if you don't change your engine oil for 20k miles running on regular petroleum oil...not synthetic. Assuming you don't starve the engine from oil, the sludge will be so thick. That's definately going to cause some serious resistance in there and loss of gas mileage and power.
Same thing with trans fluid which is one of the most neglected fluids in any car. Old sludged and gunked up transmission oil will cause more drag and friction on all parts. And same follows for the rear differential oil.
Assuming the car came with 300hp from the factory, and it's still stock. Over 10 years the car should still put out 290hp if maintained properly. Keep in mind you do lose power from wear and tear of the piston rings. Less compression = less power. Now if the engine oil was changed regularly, but the trans fluid and rear diff fluid has not been changed for 100k. I'm talking about really really bad condtion fluid....that car will be making around 260-270hp rather than 290hp. Change all the fluid, and assuming there was no permanent damange on anything...you should "RECOVER" those lost 20hp
Anyways back on topic. For example, if you don't change your engine oil for 20k miles running on regular petroleum oil...not synthetic. Assuming you don't starve the engine from oil, the sludge will be so thick. That's definately going to cause some serious resistance in there and loss of gas mileage and power.
Same thing with trans fluid which is one of the most neglected fluids in any car. Old sludged and gunked up transmission oil will cause more drag and friction on all parts. And same follows for the rear differential oil.
Assuming the car came with 300hp from the factory, and it's still stock. Over 10 years the car should still put out 290hp if maintained properly. Keep in mind you do lose power from wear and tear of the piston rings. Less compression = less power. Now if the engine oil was changed regularly, but the trans fluid and rear diff fluid has not been changed for 100k. I'm talking about really really bad condtion fluid....that car will be making around 260-270hp rather than 290hp. Change all the fluid, and assuming there was no permanent damange on anything...you should "RECOVER" those lost 20hp
Last edited by JeffTsai; 03-16-08 at 09:12 AM.
03-19-08 | 08:59 PM
#50
Well, technically you can get more power and gas mileage from changing the fluids. But, you're actually recovering lost power rather than getting more power. It's actually possible to gain a little more power by switching to synthetic, but that's a whole nother discussion
Anyways back on topic. For example, if you don't change your engine oil for 20k miles running on regular petroleum oil...not synthetic. Assuming you don't starve the engine from oil, the sludge will be so thick. That's definately going to cause some serious resistance in there and loss of gas mileage and power.
Same thing with trans fluid which is one of the most neglected fluids in any car. Old sludged and gunked up transmission oil will cause more drag and friction on all parts. And same follows for the rear differential oil.
Assuming the car came with 300hp from the factory, and it's still stock. Over 10 years the car should still put out 290hp if maintained properly. Keep in mind you do lose power from wear and tear of the piston rings. Less compression = less power. Now if the engine oil was changed regularly, but the trans fluid and rear diff fluid has not been changed for 100k. I'm talking about really really bad condtion fluid....that car will be making around 260-270hp rather than 290hp. Change all the fluid, and assuming there was no permanent damange on anything...you should "RECOVER" those lost 20hp
Anyways back on topic. For example, if you don't change your engine oil for 20k miles running on regular petroleum oil...not synthetic. Assuming you don't starve the engine from oil, the sludge will be so thick. That's definately going to cause some serious resistance in there and loss of gas mileage and power.
Same thing with trans fluid which is one of the most neglected fluids in any car. Old sludged and gunked up transmission oil will cause more drag and friction on all parts. And same follows for the rear differential oil.
Assuming the car came with 300hp from the factory, and it's still stock. Over 10 years the car should still put out 290hp if maintained properly. Keep in mind you do lose power from wear and tear of the piston rings. Less compression = less power. Now if the engine oil was changed regularly, but the trans fluid and rear diff fluid has not been changed for 100k. I'm talking about really really bad condtion fluid....that car will be making around 260-270hp rather than 290hp. Change all the fluid, and assuming there was no permanent damange on anything...you should "RECOVER" those lost 20hp
07-05-08 | 09:48 AM
#51
nicely said jeff..........but another ? is is the syntehtic worth it over the oem? i do use FULL synthetic mobile 1 oil and mobile 1 filter but ALL my other fluids EXCEPT my freon (i run 414-b and can get a/c down to 45) are oem (i have changed them they are just oem fluids)
12-30-08 | 07:52 PM
#53
Lexus Champion
Joined: May 2008
Posts: 3,347
Likes: 5
From: RI
bring it to a reputable hardware store. the fill bolt is not magnetized, so it should be a run-of-the-mill hex bolt with washer collar.
04-02-09 | 07:27 PM
#55
Instructor
Joined: Oct 2007
Posts: 1,147
Likes: 2
From: Minnesota
Easy way to tell.
No Lexus GS came with an LSD, the Toyota Aristo did. However, its often the case people put LSDs in their GSs. So, with the back wheels jacked up off the ground, spin one tire by hand. With a friend, or yourself looking at the other tire, an LSD diff will spin the other tire the same way, and the open diff will spin it the opposite way. Hope this helps.
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