Differential lube...
10-27-07, 10:25 AM
#1
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Differential lube...
What synthetic lubricant can one safely use in the differential unit on a '97 LS 400 with 95+k miles? Must only Toyota lubricant be used (is it synthetic?) or are there other brands, like Mobil or Amsoil for example, that can be used with no harm?
Thank you in advance for any info on this subject.
Thank you in advance for any info on this subject.
10-29-07, 07:02 AM
#3
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My 2c on oil.
I used to use synthetic, but switched back to regular oil.
I have realized that there is no real benefit to speak of and three major disadvantages.
1. The price. A regular oil change costs me $20. Synthetic costs around $60
2. When I use synthetic I tend to not change oil as often, while I change regular oil every 3K miles. The oil still becomes full of dirt and metal shavings regardless of whether it is synthetic or not and it does more harm to use synth. for 7K miles that regular for 3K.
3. Synthetic leaks more than regular oil. Because of its smaller molecules, it sips through old gaskets and seals where regular oil will not pass. This is especially true for older cars with high mileage.
As to the benefits of synthetic, I have never noticed the proclaimed power gain and/or an improvement in fuel economy. It may make a difference to racers and may show up on the dyno but for all other applications it is insignificant to the point of being completely useless.
I have realized that there is no real benefit to speak of and three major disadvantages.
1. The price. A regular oil change costs me $20. Synthetic costs around $60
2. When I use synthetic I tend to not change oil as often, while I change regular oil every 3K miles. The oil still becomes full of dirt and metal shavings regardless of whether it is synthetic or not and it does more harm to use synth. for 7K miles that regular for 3K.
3. Synthetic leaks more than regular oil. Because of its smaller molecules, it sips through old gaskets and seals where regular oil will not pass. This is especially true for older cars with high mileage.
As to the benefits of synthetic, I have never noticed the proclaimed power gain and/or an improvement in fuel economy. It may make a difference to racers and may show up on the dyno but for all other applications it is insignificant to the point of being completely useless.
10-29-07, 09:20 AM
#4
I used to use synthetic, but switched back to regular oil.
I have realized that there is no real benefit to speak of and three major disadvantages.
1. The price. A regular oil change costs me $20. Synthetic costs around $60
2. When I use synthetic I tend to not change oil as often, while I change regular oil every 3K miles. The oil still becomes full of dirt and metal shavings regardless of whether it is synthetic or not and it does more harm to use synth. for 7K miles that regular for 3K.
3. Synthetic leaks more than regular oil. Because of its smaller molecules, it sips through old gaskets and seals where regular oil will not pass. This is especially true for older cars with high mileage.
As to the benefits of synthetic, I have never noticed the proclaimed power gain and/or an improvement in fuel economy. It may make a difference to racers and may show up on the dyno but for all other applications it is insignificant to the point of being completely useless.
I have realized that there is no real benefit to speak of and three major disadvantages.
1. The price. A regular oil change costs me $20. Synthetic costs around $60
2. When I use synthetic I tend to not change oil as often, while I change regular oil every 3K miles. The oil still becomes full of dirt and metal shavings regardless of whether it is synthetic or not and it does more harm to use synth. for 7K miles that regular for 3K.
3. Synthetic leaks more than regular oil. Because of its smaller molecules, it sips through old gaskets and seals where regular oil will not pass. This is especially true for older cars with high mileage.
As to the benefits of synthetic, I have never noticed the proclaimed power gain and/or an improvement in fuel economy. It may make a difference to racers and may show up on the dyno but for all other applications it is insignificant to the point of being completely useless.
2-i change my dino oils at ~4k and my synthetic at 8-10k mi.
3-not entirely true, a good rule of thumb is that if you experience leakage (on older cars/higher mileage motors) is to just go up one weight in oil. ie if 5w-30 leaks try 10w-30 or 40.
4-thats very debatable, check out BTOG for a full fledged debate
10-29-07, 11:02 AM
#5
He's talking about the differential right? 
Until you do an crank case oil analysis between dino and synthetic for your particular ride it is arm chair discussion. Even at that, there are many of them net wide. It's your car so maintain it how you feel best. I'd suggest synthetic fluids across the board for the LS.
Until you do an crank case oil analysis between dino and synthetic for your particular ride it is arm chair discussion. Even at that, there are many of them net wide. It's your car so maintain it how you feel best. I'd suggest synthetic fluids across the board for the LS.
10-29-07, 07:17 PM
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Steveski: What weight syn do you use in your diff unit? Are you speaking of synthetic engine oil or diff lubricant, or do you sue regular engine oil in the diff?
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10-29-07, 07:33 PM
#8
You don't use regular engine oil in the diff... he's talking about synthetic gear oil in the specified weight.
You need SAE90 or equivalent oil... 75W-90 sounds good to me. I am going to pick up some Royal Purple or Castrol Syntec this weekend and change my diff oil as well.
You need SAE90 or equivalent oil... 75W-90 sounds good to me. I am going to pick up some Royal Purple or Castrol Syntec this weekend and change my diff oil as well.
10-30-07, 06:26 AM
#9
Yes - definitely not engine oil in the Diff case. I use Mobil 1® Synthetic Gear Lube LS 75W-90 and it has been fine. I also use Mobil 1 SYN in the engine and ATF SYN in the power steering. It costs more than conventional oil but I am sold on it.
11-08-07, 08:29 PM
#14
All The Above Synthetic Oils Are Great I Use The Redline Gl5 For Limited Slip Rear Ends Which Some Of The Lexus Rear Ends Are. Yes Synthetic Lube Does Cost More And That Is Why Bmw Mercedes And All High End Cars Are Now Using It Including Porche And They Change The Motor Oil At Around 15to 18,000 Miles And No Problems. Amsoil Is Probably The Best Followed By Mobil One Redline Royal Purple Etc. They Are All Very Good For The Lexus By The Way Somebody Took A 99 Lexus Supercharged The Motor To 1000 Horse Power With Out Any Modification And It Has No Problems This Is How Good The Lexus Motor Is Anothe Story Is That The Lexus Motor Is The Only Car Motor That Can Come From The Crate And Put Into An Airplane The Only Car Engine In The World That Is Able To Do That Faa Approved Due To It's Quailty. Bmw Mercedes Try That.