My Lexus LS400 98 has over 300k mile on it. When is it recommended to change the Differential oil? and how to properly clean and maintain it? Do not have any service record of it. And how to check if its in good condition?

 

this might prove useful...
http://www.lexls.com/tutorials/suspe...iffchange.html

Owner's manual should give you recommendations on how often to change it... don't have mine readily available, but seems like every 30k sounds about right.

Color and metal deposits that collect on the drain plug magnet will be tell-tale signs.

As a single digit poster... might want to take some time to read the FAQs and stickies at the top... most of your normal maintenance questions are addressed there.
Welcome to the club.

 

i put redline in mine

 

Put Valvoline full synthetic diff oil in both of my LS400's and believe it or not my MPG increased approximatly one mile per gallon!

 

Running Mobil1 synthetic in mine, no LSD additive since it's a torsen now

 

Mobil 1 or a compatible weight gear oil that is available in your area. 100K intervals is fine, I've tended to be a bit early and have done it at 100K and then at 150K. With 50K miles on it, it came out looking and smelling as if it were put in the day before.

This derails the discussion: I would also suggest inspecting the tranny fluid since you are being systematic at making sure your LS is in top running order. If it is red, you are good, any darker shade of burgundy to black, do the partial drain routine. We have discussions on this in the FAQ to reference.

With the differential and tranny, make sure you have a fresh washer, do not reuse the old one.

 

i used pennzoil gearplus 80W-90 GL-5. owners manual says to use 80W-90 GL-5 so that's exactly what i gave it

and yeah make sure to use a new crush washer for each of the diff bolts

 

trans fluid change(fluid exchange)=30,000
brake fluid change=every 2-3 years (im in california) dot 4 btw which is a little more hygroscopic than dot 3
coolant change= every 3 years or 25,000 miles (which ever is first)
power steering fluid= i turkey baste out of the reservoir every 6 months,then have it flushed every few years
diff. fluid=follow ra40's advice

 

I change mine at 75K with Amsoil. I ran a tube from the fill hole up out above the right rear tire and put a funnel on the end of the tube. Keep a catch pan under the rear end. Pour and fill till it won't take anymore. Pull out tube and let it run until it quits. Replace plug and make sure you write down when you changed it.

 

I have LS400 98 model over 300K miles on it. Is is possible to open up the rear differential and get it cleaned then put the new oil in it? And should i put LSD gear oil GL-5 85W-90? i dont have the service manual

 

Draining the fluid is usually sufficient and an indicator if more attention is needed. Like metal or other contaminants that come out in the oil indicating wear.

 

If 98's are like the older ones then GL5 85W-90 will work. I don't know about the newer stuff but the older ones did not do positraction so no need for special gear oil. Trac was the posi traction.

 

no LS400 ever came with factory "posi" (limited slip).

standard or synthetic 85w-90 will be fine.

 

http://www.lexls.com/tutorials/suspe...iffchange.html

older car, but same principle!

 

My Mechanic put ELF Gearelf 4 Gearbox oil 85W140 API GL-4
is that oil good for LS having 318K miles on it?