martinb820

I have a '99 RX300 with 26K (this isn't a typo) relatively easy miles.The Lexus Maintenance Manual is vague about fluid change intervals: It says to replace the ATF, transfer case and lsd lube (it has the limited slip diff) at 30K/24 months for severe use, and to change the lsd lube at 60K/48 months for normal use.

What about normal use intervals for the transfer case and ATF? All the book says is "If the vehicle is operated under the 'Special Operating Conditions' ... change the oil when scheduled." This seems to imply that changes aren't needed for normal use, which seems like it could get expensive later...

BTW, the trans fluid was changed at 14K/5 years ago.

Also, do these lubricants break down as a function of time, or does it make sense to wait to a certain (more reasonable than "never") mileage?

Thanks!

salimshah

Since your number of post is low, so a warm welcome to you.

Although all posts are welcome (that follow CL guidelines), but I urge every one to browse through the forum couple of days and use the search feature. If you start a new discussion on old topic, we get the same discussion again. One of the most discussed subject is the transmission and transmission fluid. General consensus of the board is "once a year' or about 15k miles.

If you look at the physics, the transmission fluid is not exposed to contaminants and only shear. If you dont drive much then you can possibly do a 5 yr of 15k miles [You may like to get an answer from dealership as they represent Lexus and not CL).

Engine oil is a different discussion as it picks up combustion bye products. So an oil change is recommended for seldom used vehicle (0nce every six months ,, once again check with dealership).

Now specific to your vehicle:

Try to break it in ,,, instead to a harsh switch ... no activity to work-horse. Time and age take their toll on leather, rubber, bushings and even bearings. Regular use keeps them moving.

A bit if not-so-good news, the limited slip diff is a bogus item. I am saying this to inform you so that you should not count on it. The drive is due to viscous fluid and that gives all the slip in the time of need. The only viable configuration for bad roads in the early RX had was with "traction control" . This would apply the brakes on the wheel with no traction. The only competitor to Lux SUV was Mercedes back then. The rigged up a setup and poor RX could not get up. FWD RX with traction could struggle up, but that was listed in small print.

I hope your RX was garaged most of the time. Nature has its ways to take things back to their natural state.

Salim

martinb820

Hi Salim

Thanks for your reply. That interval for the trans fluid makes sense; I did it at 14K, as noted. What is less clear is how often to change the transfer case and differential lubes. I'm still looking for ideas on those...

Thanks,
Martin

carguy07

Are you able to DIY these? The tranny and transfer case fluids will only run you about $20 to do with quality synthetic. I really can't see gear oil breaking down with age vs mileage, but I like to over maintain and it is always nice to get the break in junk out of there early. Tranny should be fine too, but as cheap and easy as it is, I would go ahead and do it at at the same time.

Brake fluid would be high on my list if it has been in there for a while.

thomas1

The limited slip was on the rear axle, it was a option, however it probably didnt do much...I have the original sales slip with that listed as an option which my 99RX had. However with the viscous coupling the rear drive was only about 20%.....So for the correct fluid I would use one for the rear differential that is limited slip compatable if the car is AWD

martinb820

Thanks for the replies. In no particular order, my responses are below...

Overall, I guess common sense has to be the guide, since Toyota doesn't seem to provide firm miles/months recommendations. Advice from the dealership during the early years wasn't all that useful (I'll leave it at that).

I had the timing belt changed yesterday, and also had the brake fluid replaced. I last had the brake fluid changed five years ago/11K miles, so it was way overdue. I was getting nervous about the timing belt's age, and figured that it was relatively cheap insurance against an expensive potential problem.

I'm going to have the transfer case and differential lube changed at about 30K. The transmission fluid only has about 11K miles on it, so it's good for awhile longer. The coolant is less than two years old, and I'll have it changed at the two year mark.

WRT having been garaged, it has been since new and is in basically showroom condition. Definitely, keeping it out of the sun and away from the elements makes all the difference.

WRT to the limited slip - it may not be optimum, but the overall combination of AWD and whatever benefit there actually is from the (not so?) limited slip works very well in the snow. At least nothing that's likely to come out of the sky in NJ is going to stop it!

jbl-1985

In a word, "Wow".

Probably too late to ask but were you able to note the condition of your old timing belt when they replaced it?

martinb820

No, I didn't think to check the condition... It would have been interesting.

iceman13

trans ATF : every year ( no doubts as the car is ageing hence a yearly ATF change would keep the internals cooler )
engine oil ( 5W-40 Full syn ) every 3 months
radiator coolant - every 6 months once ( twice a year )
other fluids ( brake ) - once a year ..

that's how i keep all my cars here

carguy07

I was just thinking the other day that I must truly be the only one who over maintains their car, but you got me beat.

40 weight oil is too thick for this car IMO, coolant every 6 months? Toyota red seems to last forever, but I think I'm going to do it now that I just hit 75K miles. Brake fluid yearly? I'm more like 2-3 years on that. I'm just glad that there are people who have the disease worse than me. Who ever buys your car used will really get hooked up.