Natey2

2005 LS430 oil pan
2005 Lexus LS430, 135K miles.Local Toyota dealer service dept diagnosis: "Transmission Oil Pan: (LEAKING AT GASKET) TRANS PAN GASKET AND ORANGE DIPSTICK ATF The oil pan is the removable metal chamber or bowl(usually of sheet steel or cast alloy) at the bottom ofthe Transmission into which the oil drains to be stored. The Transmission fluid drain plug is found at the bottom of this pan and can be removed to allow the old fluid to flow out of the vehicle during a fluid change." (pic attached) Quoted cost $700+

Natey2

Is this the same lower pan as the engine oil pan? A few years back they said the threads on the oil pan were worn and wanted to replace the whole pan. When I declined, they provided a larger drain plug that stopped the minor leak. Could the stain be from old oil and not transmission fluid?

I'm not seeing any new stains where my car is parked at home, and the fluid levels look ok.

TominPT

That is the transmission oil pan, and it is not the same as the engine oil pan. The dealer says the gasket and or the dipstick o ring are leaking and that would explain why the transmission pan is oily. If you are not seeing any drips or stains at all under the car, the leak may be very small and you might get away with just thoroughly cleaning the pan and if the leak is very slow just living with it. If you want to repair the leak you need to drop the pan and replace the gasket and the dipstick o-ring. I believe there are threads here on the dipstick o-ring leak fix, apparently it is not all that uncommon with higher mileage vehicles.

By the way, if you clean thoroughly the transmission oil pan, and the leak comes back, if the leaking oil is reddish, it is transmission oil. If it is black, it is engine oil leaking from somewhere from the engine, probably at the back of the engine. Look for engine oil leaks while you are under the car.

Edit # 2: The $ 700 quote to drop the pan and put in new gaskets seems way high. I just had a toyota dealer do a complete timing belt job on an LS400 for under $1,000 labor, and that is MUCH bigger job..

JffGRY706

2005 transmission has no dipstick
try again

bradland

Most of the pan is wet which suggests the bolts holding the pan to the trans. IIRC there are 18 or 20 of them in total.
Start with the basics-
These small bolts become loose over time and the condition of the gasket also changes. The bolts aren't "loose" per se but they aren't as tight as they should be. They become just loose enough to allow fluid to sweat past the gasket.
Given enough time it will accumulate and appear as a serious leak. Clean the entire area thoroughly so you can monitor moving forward. Tighten ALL the pan bolts slightly. They just need a snug don't overdo it, a quarter turn or less might be all they need.

911LE

There is no gasket to speak of here either. It was sealed with fipg from the factory and should be resealed with the same. Super cheap and easy fix.

Natey2

You're right. My bad. The yellow dipstick is the oil level.
How would I tell if too much transmission fluid has leaked? The car still shifts beautifully.

Natey2

Anyone know a good independent mechanic in the San Diego, CA area who knows Lexus LS cars well enough to do this? I've always taken my car to the Toyota dealer: they know the 2UZ-FE engine (Toyota Tundra?) well, and this is the 3UZ-FE engine. But their service prices are staggering: they wanted $1400 to replace a door lock actuator, per door!

TominPT

Any competent mechanic should be able to drop the pan, replace the gasket, and fill to the proper level with Toyota WS fluid. Its really a DIY task, on a scale of 1-10 a 2 or a 3 if you have the right tools.
You can use a traditional gasket or a form in place gasket as noted above.
The refill procedure is described in a million posts in the sealed transmission thread in the FAQ section, below is a link to a guy doing it with a temp gun pointed at the pan to make sure the fluid is at the right temp when opening the overflow plug.

To tell if too much fluid has leaked already, and condensing the procedure somewhat, you have to have the transmission up to the proper temp (115-130F IIRC), open the overflow plug with the engine running in park, and if nothing comes out of overflow, shut off engine, add 0.4 L fluid to the fill port, start up engine again, make sure temp is within range, open overflow plug, and drain until just a trickle comes out, close overflow plug, you're done. Car must be level doing this service.

While the pan is off, its a good time to replace the filter in the bottom of the transmission.

Good video on dropping the pan and replacing the gasket, and refilling to the proper fluid level in an '05 LS430




Link to a gasket for the transmission pan:

https://parts.lexus.com/p/lexus_2005...516860010.html