Hello All, (including DougHIII & Woodranch)

I recently changed my diff and transmission fluid. Here are the UOA's. Note, they are from the lab right by my house. I really wanted to have Particle Count, FTIR, Viscosity at 100c and the Index. I will have the samples tested at a later date this month with those additional data points from a different lab. I also wished I could have run new samples to see where they lie in the picture. My reference data base is very small on the trans and diff fluids.

I will add, I wish I had taken photos of the diff fluid at 24,110 miles. There were significant chucks of metal flakes coming out. Break in wear, but still wishing I had gotten this all out at the 10,000 mile marker. The trans fluid "looked" clean when it came out but was a little dirtier than I'd like.

diff swap cost $18 in fluid and about 20 minutes. The trans swap was about $60 and about 45 minutes.

mackey 8-1-17.pdf

 

Can you explain why your trans only cost $60,eg filter, gasket, oil, man that is cheap. I had a FULL trans service with 12 litres WS oil $200 plus kit and labour $300 =$500 this is in OZ just interested in the costing cheers.

 

Well I do my own labor and it's very easy on this unit.

I did not use the Toyota fluid, so I saved a bunch of money there. I didn't drop the pan, there is about 60% new fluid in there, I'll swap more new fluid in there soon.

 

How much of a pain is it to do the trans fluid on these? Can you just drain and then refill to a certain amount and be done with it? Or is it one of those deals where checking the fluid level is sort of a pain in the ***?

-Mike

 

It wasn't that hard, you will need a pump to force the trans fluid in the trans. Trans needs to be running between 113f-130 to check for the level. I would definitely not skip checking the fluid level part. On a lift it's great, at home it may be harder to do.

The diff took less than 5 minutes. Well it took longer because I was looking at the shards of metal but it should have been less than 5.

 

What type and brand of diff fluid do you guys recommended for a TVD equipped RCF?

 

I believe the TVD calls for ATF and Diff fluid. I don't know the specific procedure. It's probably just drain and fill.

I would go with Redline, Amsoil, Renewable Lubricants for the diff fluid. Amsoil can be had for the same price as Mobil or Valvoline at the store. Diff fluid isn't as complicated as Engine oil.

 

Daniel,
Any chance you can do a diy write up?
I'm sure many on here would be interested. I'm definitely interested.
I've been ******* my car pretty hard, thinking some new tranny & diff fluid would make me feel better...

so what brand fluid did you use for the ATF and the diff?
I have TVD on mine so what diff fluid do you recommend?

 

Thanks for the info.

What about a transmission filter?

Do I need to drop the transmission pan? Gasket replacement for the pan?

ANY other replacement parts needed? I remember on the RX and other Lexus models there is some sort of plastic tubing inside the pan and sticks out to the side that acts like an overfill hole?

Specs on the automatic transmission fluid? On the differential fluid?

I'm familiar with the measuring the temperature of the automatic transmission fluid in operating temperature with a laser gun and replacing under specific temperature measurement. This is similar to the automatic transmission fluid replacement in my MB SLK55 AMG. Another way to do it without measuring the temperature (btw, this is not what the service manual says to do) is to have the car on jack stands (DOUBLE make sure ALL SECURED) and drain the automatic transmission pan fluid when the fluids are COLD onto a BIG CATCH PAN SO YOU CAN LATER MEASURE EXACTLY HOW MUCH FLUID CAME OUT. Then clean the pan and put in the new filter and gasket and torque down the pan evenly to spec (very important ). Then fill with the proper spec fluid EXACTLY THE AMOUNT OF WHAT YOU DRAIN OUT.

 

does non tvd require rear diff fluid change ? asking for a friend......

 

still on the original OEM Trans fluid in my IS-F at 62k...look at the IS-F forum as these cars use the same trans....many folks are seeing low levels which cause flashing at cold temps.

Also, your home address is viewable on that .pdf...i would edit and remove...people are weird.

 

Mingo, there is a write up on the GS forums, not sure where though.

I went with Amsoil on both the diff and the trans fluid. There are many good options out there.

This was a drain and fill, not a flush, no filter change or pan dropped. Filter is likely still fine at this point based on the UOA, will have PC and FTIR soon.

The answer is it depends. Truthfully, you never know much without a UOA, otherwise you're just guessing. I wish I could go back and have this fluid changed out at the 5,000 mile marker. I didn't follow my own advice and followed that of "ASE" and "dealer technicians", still pounding my head on that one.

Not sure what you're getting at. I have UOA on both diff and trans, albeit not the most complete UOA I wish for. I was very well justified in changing both fluids out. You can go a long time with the same fluid in the trans, I come from the trans business, let me tell you one thing.(this is where I got started with UOA) If people had just replaced their trans fluid once in their lifetime, they wouldn't have had a trans issue at 140,000 miles. People think these cars can't go 400,000 miles, because they're trained to think that way.

I drive 50-75,000 miles a year, because I do so many straight shots, my mileage is more like 15,000 miles for the typical user and not 24,110. Again this is an estimation on knowing how to correlate mileage to wear that is not linear.

Old childhood home, but any weird guests are welcome to PM me for the real address!!! LOL

Keep in mind, Lexus needs to sell a "reliable" car & "low maintenance" and "cheap to afford". It's why they recommend conventional oil from the factory, they wanted to keep oil change prices low because how would a $200 oil change go over on this forum? So they're definitely not going to tell you, yeah change the diff fluid and trans to get the break in junk out. I see the service intervals on these things and it's a joke. Aisin Warner for a fact, does not recommend those intervals to their customers. I can't remember properly as it's been a long time, but from what I recall, Aisin's recommendation is less than 50,000 miles for a fluid exchange on these 8 speeds. Which again on some of my previous posts in other topics, shows how much engineering is booted out of the table when something has to be sold.

Many performance only oriented manufacturers recommend diff, trans and engine oil changes at 500 miles. Lamborghini is very adamant about this to new vehicle owners. Why? because the break in wear and particles will shorten the life in the long run. Think of it this way......

Diff X - oil changed at 100,000 miles -> never changed again. Goes to about 350,000 miles.

Diff Z - oil changed at 10,000 miles -> never changed again. goes to about 700,000 miles.

The break in wear will chew up the diff in the long run. Now I know what some of you will be saying next, but my grandma's car didn't get that or who's gonna drive to 400,000. Well there's more to it than just longevity. Fuel economy is the first that comes to mind, ride quality, ride comfort and power to name a few. I like to load the torque converter on this thing and squeal tires, launch and drift. I like to know my equipment can safely handle the drive, no matter what I throw it's way.

Plus there are plenty of cases of blown diffs on lots of vehicles, you'll just never hear about them on a forum.

 

Blown diffs are from only from abuse. Toyotas wheel hop like a biotch from the factory, and if you do this, you will hurt your diff. If you don't, you won't. Toyota diffs, if not abused; even when not meticulously maintained, are very reliable. There was no appreciable wear on the ring and pinion in my IS F when I installed the OS Giken LSD (and SuperPro diff bushings to eliminate wheel hop), and the backlash numbers were in the middle of the OEM tolerances with 130k miles on the odometer and only one oil change in the life of the car. So, as much as anyone wants to say - "you should" - the reality is, when you take it apart and measure it, you'll be surprised to see there is very little wear, even if you are negligent in your maintenance schedule.

There is a thread about ATF in the Aisin AA80E in the IS F forum. It's pretty long. The reality is, you can go a long time on the OEM fill as long as you keep the level where it should be. I do not disgree that ATF dies after some time, but I will also say I have not experienced issues unless the level has been low. I (fairly recently) replaced my pan gasket, filter, and the ~5.5 quarts of WS fluid in my IS F, but I went a very long time on the factory fill. I really doubt someone who is NOT abusing the gearbox should expect 200k miles of service before the gearbox gets unhappy.

Also - if you are braking and applying the gas to get a good launch from this gearbox, Lexus does not recommend more than 8 seconds of this foolishness based on their torque converter stall testing procedure in the FSM. This is truly the quickest way to degrade the quality of your ATF, and IS F owners have found no advantage to brake torquing their cars at the drag strip. As always, YMMV.

 

How many miles when you changed the diff oil?

Well it varies for sure, in my case at 193ppm of iron, that is very high. I should have changed it sooner. I have FBO GT R's tracking after 4,000 of pure track mileage, about 6 hours at a time, that don't even have that much wear in the diff. Usually 75ppm. As I mentioned break in wear should be flushed out, then you could get away with never changing the fluid again. It was also only $18 for Amsoil in the end anyways.

All of those particles affect ride quality and fuel economy/power over time as well, I know a good guy at Timken who spends all day listening and calculating how to reduce NVH. One of the things they always bring up at STLE conventions is how dirty fluid really takes a toll on NVH. I'll have an ISO code for both soon.

I'll have another UOA at 50,000 miles to see where the diff sits in terms of wear.

I could have definitely gone a bit longer on the transmission fluid but I just didn't want to. For a brand new trans, the wear numbers were definitely on the low side. I will note while my fluid wasn't low, the shifts are slightly smoother at low speeds, could be new fluid but I think Amsoil finally has a better formula than Toyota. I'm a big fan of OE transmission fluids but I wanted to give the signature series a shot. Amsoil has really been stepping up their formulas both in the engine and transmission department. Will have better UOA's on both of these in the next week. We'll see what the FTIR and PC show as ICP(wear metals) won't read the big particles and those are the killers.

In the end, everyone drives differently, YMMV as you said.

 

As I recall, I had about 60k on it. Pretty sure I did it at the same time I did my valve lash inspection, and pretty sure that's the Lexus recommended first change. I'd be a lot more worried about iron chips from grinding on the side of the diff case to get the Giken unit in place than I would be about the wear particles hurting the longevity of the bearings. FWIW, I ran Lucas diff oil for the first 1000 miles after putting the Giken in, and replaced it with Giken's recommended oil which I changed at their recommended 20k mile interval (set a reminder in the maintenance section for it). I really don't want to have to remove that thing and get it rebuilt any time soon.

When I did the road race motorcycle engine building we always dropped the oil after break-in (which only take about 30 minutes total) and dropped the oil pan to clean out all the swarth collected there from initial fire and ring seating. I am sure you are right about the longevity of differentials and transmissions, but realistically these devices will be rotting in a junkyard long before that based on statistical averages for service life. Their first owners will not see more than a 1-2% degradation over the life of their ownership, and few of these units will make it to even 200k miles. Those that did get the early oil change will have happier second and third owners, but few first owners keep a car for primary transportation much past 150k. So we are back to what is expected, what is prudent, and what is ideal. Very few owners even consider what is ideal, much less act on it.