LS - 3rd Gen (2001-2006) Discussion topics related to the flagship Lexus LS430

Oil leak underneath car between rear tires

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Old 12-03-17, 07:00 PM
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asc2000
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Default Oil leak underneath car between rear tires

I purchased 2004 LS 430 Silver with 59k miles last week from a private seller. Just found oil leak underneath between rear tires. See the pic. I thought this car would be trouble free considering low miles. Is this crankshaft? Do i need to take it to the dealer to get it fixed? Both rear axles look fine with no leak. Anyone has the same or similar issue like this? Please advise. Thanks.
Attached Thumbnails Oil leak underneath car between rear tires-img_2750.jpg  
Old 12-03-17, 07:20 PM
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yoitskenn
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That’s the rear differential. If that’s not the leak, it could be coming from the front, blown to the rear while driving
Old 12-03-17, 07:36 PM
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asc2000
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Originally Posted by yoitskenn
That’s the rear differential. If that’s not the leak, it could be coming from the front, blown to the rear while driving
Thanks. I need to double check but i did not see any flowing from the front. If the leak, that means the fluid needs to be changed?
Old 12-03-17, 07:39 PM
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Hopefully it's a small problem. First step is to find an independent mechanic with lots of Lexus experience. Ideally someone that's worked at a Lex dealer. You'll save a lot of money. The guy that works on my car (Lexus factory certified) is willing to show me what needs to be fixed while car is up on the rack. The local dealer won't let me into the garage. Good luck.
Old 12-03-17, 07:46 PM
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asc2000
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Originally Posted by tallcaguy
Hopefully it's a small problem. First step is to find an independent mechanic with lots of Lexus experience. Ideally someone that's worked at a Lex dealer. You'll save a lot of money. The guy that works on my car (Lexus factory certified) is willing to show me what needs to be fixed while car is up on the rack. The local dealer won't let me into the garage. Good luck.
I purchased it on Monday and took it to the dealership last Friday for brake fluid flush and multi point inspection. I was told not to worry about the car. Excellent condition!! Contrary to what the dealer said, I got this problem today. interesting... anyhow i also hope this would be a small problem. Hope that just changing differential fluid would fix the issue. If not, I will be disappointed.
Old 12-03-17, 07:59 PM
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Is it dripping on the floor under the differential? Is that how you found the problem? Did the multi point inspection include putting the car up on a rack?
Old 12-03-17, 08:18 PM
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Originally Posted by asc2000
I purchased 2004 LS 430 Silver with 59k miles last week from a private seller. Just found oil leak underneath between rear tires. See the pic. I thought this car would be trouble free considering low miles. Is this crankshaft? Do i need to take it to the dealer to get it fixed? Both rear axles look fine with no leak. Anyone has the same or similar issue like this? Please advise. Thanks.
Hey man put your finger on the puddle that's on the ground and smell your finger, if it smells like rotten sulfur and is super repulsive it's differential fluid.
Your car is older and has low miles it probably sat more than it was driven, when cars sit or age gaskets, seals, etc degrade and begin to crack.

If it's your differential get a can of brakekleen

them spray the hell out of the differential then let it run for like 5-10 mins and see were your leak is it could be your pinion seal or your differential cover. The repair for the seal would be to unbolt the driveshaft take the old seal out etc, if it is the differential cover unbolt the cover scrape the old gasket/silicone off. Use the brakekleen I posted above to clean out the diff housing wait for it to evaporate then use this
On the housing let it cure for 15 mins put the diff cover back on then tighten the bolts down thenbtake the drain plug out fill with fluid and your good to go. If you want a more detailed description on how to do the rear diff cover pm me i will be more than happy to help.

Last edited by 05ls430518; 12-03-17 at 08:33 PM.
Old 12-03-17, 08:22 PM
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Jabberwock
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It is possible but somewhat unusual for the rear differential on the LS to be leaking unless it was recently serviced and perhaps drain nut and washer not correctly installed. The diff does not hold much oil and it is not under pressure so its not likely to leak under normal use. Much more likely is leaking valve cover gaskets that drain down to lower part of engine and plastic shield and fall to ground from there. Also a loose or bad gasket on oil filter or stripped oil drain plug may cause this but less likely. Worse case is engine seal, crank seal or AT seals. You need to take it to dealer or independent shop and have them trace and diagnose the oil leak.

In some cases leaking valve cover gaskets can be corrected in short term by checking valve cover gasket bolts. Many posts concerning loose valve cover bolts over time caused by shrinking gasket - tighten bolts carefully (do not over tighten) can stop or minimize leak for an indeterminate amount of time (weeks, months, years...hard to tell) .
Old 12-03-17, 08:37 PM
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asc2000
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Originally Posted by tallcaguy
Is it dripping on the floor under the differential? Is that how you found the problem? Did the multi point inspection include putting the car up on a rack?
Yes dripping on the floor a bit..that is how I noticed and took a look underneath. No clue how they did the inspection. They gave me a check list like tires, brake, fluids, etc. but did not say anything about this differential fluid. That means, I guess, they did not put up on a rack... I still can't believe how they missed it.
Old 12-03-17, 08:48 PM
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Originally Posted by 05ls430518
Hey man put your finger on the puddle that's on the ground and smell your finger, if it smells like rotten sulfur and is super repulsive it's differential fluid.
Your car is older and has low miles it probably sat more than it was driven, when cars sit or age gaskets, seals, etc degrade and begin to crack.

If it's your differential get a can of brakekleen

them spray the hell out of the differential then let it run for like 5-10 mins and see were your leak is it could be your pinion seal or your differential cover. The repair for the seal would be to unbolt the driveshaft take the old seal out etc, if it is the differential cover unbolt the cover scrape the old gasket/silicone off. Use the brakekleen I posted above to clean out the diff housing wait for it to evaporate then use this
On the housing let it cure for 15 mins put the diff cover back on then tighten the bolts down thenbtake the drain plug out fill with fluid and your good to go. If you want a more detailed description on how to do the rear diff cover pm me i will be more than happy to help.
Got it. Thanks for your help. I did not smell it but I feel it was thin, not thick. Is the differential fluid thin? Given the way it looks on the entire differential, I feel this leak would not be just happened last month.. it would have been slowly going on for months or years. I will see if I can do follow your suggestions tomorrow morning. Thanks again.
Old 12-03-17, 08:54 PM
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asc2000
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Originally Posted by Jabberwock
It is possible but somewhat unusual for the rear differential on the LS to be leaking unless it was recently serviced and perhaps drain nut and washer not correctly installed. The diff does not hold much oil and it is not under pressure so its not likely to leak under normal use. Much more likely is leaking valve cover gaskets that drain down to lower part of engine and plastic shield and fall to ground from there. Also a loose or bad gasket on oil filter or stripped oil drain plug may cause this but less likely. Worse case is engine seal, crank seal or AT seals. You need to take it to dealer or independent shop and have them trace and diagnose the oil leak.

In some cases leaking valve cover gaskets can be corrected in short term by checking valve cover gasket bolts. Many posts concerning loose valve cover bolts over time caused by shrinking gasket - tighten bolts carefully (do not over tighten) can stop or minimize leak for an indeterminate amount of time (weeks, months, years...hard to tell) .
I am with you... this is rare for LS 430 but in my second look, the leak is not coming from the front.it is isolated from the front.I confirm. I see the oil leak on the entire rear differential from top to bottom, not other areas. Thanks for your observations though. BTW, the previous owner never changed any fluids, other than regular oil/filter change. I received copies of service history but no differential fluid done.

Last edited by asc2000; 12-03-17 at 09:28 PM.
Old 12-03-17, 09:05 PM
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Originally Posted by asc2000
Got it. Thanks for your help. I did not smell it but I feel it was thin, not thick. Is the differential fluid thin? Given the way it looks on the entire differential, I feel this leak would not be just happened last month.. it would have been slowly going on for months or years. I will see if I can do follow your suggestions tomorrow morning. Thanks again.
No problem man. Gear oil is like any oil the outside temp will really have a big role in it's viscosity, but the smell is a dead give away gear oil has a distinct smell and like I said above it's really nasty smelling it's generally like rotten sulfur ....or the DMV lol .In my opinion gear oil does feel thinner than regular oil or transmission fluid but that is just my opinion.
If you need to smell the oil on your engine oil dipstick and compare it to the fluid that's leaking. I agree with you that leak has been going on for a while the built up black gunk is an indicator.
Old 12-03-17, 09:31 PM
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Originally Posted by 05ls430518
No problem man. Gear oil is like any oil the outside temp will really have a big role in it's viscosity, but the smell is a dead give away gear oil has a distinct smell and like I said above it's really nasty smelling it's generally like rotten sulfur ....or the DMV lol .In my opinion gear oil does feel thinner than regular oil or transmission fluid but that is just my opinion.
If you need to smell the oil on your engine oil dipstick and compare it to the fluid that's leaking. I agree with you that leak has been going on for a while the built up black gunk is an indicator.
Got it. thanks again. do you think i don't have to change the differential fluid given the situation, in addition to what you have suggested?
Old 12-03-17, 09:47 PM
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Originally Posted by asc2000
Got it. thanks again. do you think i don't have to change the differential fluid given the situation, in addition to what you have suggested?
I would honestly just because that leak has been going on for a year at least and that leads me to believe they probably have not changed the fluid, also if it has been leaking for that long it might be running low.

https://www.clublexus.com/forums/ls-3rd-gen-2001-2006/738556-diy-rear-differential-drain-and-fill-ls430.html

This is the link to a drain and fill someone on the forum has done. Take the top fill plug out and insert your finger into it and pull it out if your finger has some fluid on it it means it's full enough, but I would identify the leak, fix it and put new fluid in.
Old 12-04-17, 05:54 AM
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Originally Posted by 05ls430518
I would honestly just because that leak has been going on for a year at least and that leads me to believe they probably have not changed the fluid, also if it has been leaking for that long it might be running low.

https://www.clublexus.com/forums/ls-...ill-ls430.html

This is the link to a drain and fill someone on the forum has done. Take the top fill plug out and insert your finger into it and pull it out if your finger has some fluid on it it means it's full enough, but I would identify the leak, fix it and put new fluid in.
Thanks again. Got the link and it shows how to do it. Great. I just got brakleen and the green gasket maker from Walmart. I am ready to tackle the work. BTW, the oil has no smell at all. That means it may be the pinion seal leaking.. don't know...

Last edited by asc2000; 12-04-17 at 05:57 AM.


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