i'm pretty sure its smooth in the morning. I will check tomorrow and let you know.

 

Cool. Unless you warm it up for a long time in the morning, you should feel the lag if you give it some gas in the first few blocks. When the car is being driven (vs warming in a location in Park), it takes me about 1-2 minutes before the car is warm enough to not cause the lag.

 

Anyone know how to change the tranny fluid? Any recommended fluid? Any parts needed, ie: filter, gasket? Changing the fluid is something I haven't done...yet. When you say "flush", do you know the procedure the mechanic used? I'd guess replacing the fluid...driving for a few miles...replacing fluid again...repeat until fluid on the dipstick checked to be clean after driving a few miles.

 

well, I didn't feel it this morning. I did not warm up the car. The temp needle was on the "C". I know I've experience this lag in the past and would have to say that flushing out the tranny fluid completly did the trick.

 

From what I remember the mechanic telling me...it took two people to do. One person in the car starting the engine and stopping....while he was there draining and refilling the tranny fluid. There were specific steps that I don't quite remember, but I believe the important thing is to not drain the fluid completly. He showed me the first 4 qts of fluid that came out of my car and it was black sludge. If I had my camera with me, I would have taken a picture. So I guess depending on how dirty your tranny is, the more fluid you'll need. It took 20qts for mine. I'll have to check on the fluid but I'm pretty sure we just used the stock toyota fluid...but that may have been for the differential. Anyways I'll be back at the shop for my dad's RX this friday and will find out more details.

 

jawnthen...I check the maintenance threads for tranny fluid...seems Lexus mechanics and experts stress using only Toyota tranny fluid. Can't go wrong it seems.

 

Cool. My temp in the morning is usually below the "C" and it takes a little time to get to "C". Hmmm.

 

Bought a case of ATF type-IV from the dealer last weekend and two 5qt jugs of Mobil synthetic 5W-30 motor oil from Wally-world. Did a drain/fill of both oil and tranny. Drove for a few miles then drain/fill again, this time replaced oil filter and plug gasket. While I was working I had the ETCS fuse out (#35 in engine compartment fuse box). When all was done(fuse replaced), the car seemed like it was reborn. Shifting seems much smoother in the morning (and all occasions...even at WOT), although it still needs warming in the morning. Didn't surprise me. Also noticed the tranny holding the gears a little longer...this may be due to resetting the ETCS, but I like it...PWR mode, VSC off, at 50MPH give WOT and she shifts/accelerates much better...WOW a definite improvement.

I did find a potential problem...when draining the tranny fluid the first time the fluid poured out like the oil would drain. What I mean is, the force and time it took to drain seems long for only 2 qts. I was sure there was more than 2 qts drained. I then checked the dealer invoices from the previous owner for the last tranny fluid change and found 4 qts listed. This can't be correct. The owners manual specifies 2 qts. So my question to CL is, can overfilling harm the tranny? Since I haven't driven my new (used) gs400 very hard since buying it, I hope all is still ok.

CL...Thanks for the advice and tips found through this site!

 

Is 44,000 miles too early to do this tranny flush? I really wanna tighten this tranny up.

 

I wouldn't think anytime is too early. How could it hurt the tranny?...dunno. But I figure draining only does leave a little old fluid in the tranny. So, if you can afford the extra $ to drain it a second time you can rest assured nearly all old fluid is out.

 

PWR button on?

btw. it's reallly cold up here now and if I don't let it warm up enough it doesn't downshift quickly and just does it's own thing until when it's quite warm

 

Mine tranny lag too, But mine lags when I'm driving hard, I 've tried everything fluids etc. only made a little difference but after I install the Blitz Automatic Transimission Cooler and it makes a big diff , don matter if the tranny is hot or cold, The Tranny responds better then b4 and finally seems like it's responding with the Motor. Tom's has one like that too.

 

The 4 quarts that was on the dealer invoice was probably from 2 sequential drain and refills of the A/T. Each drain and fill removes 2 quarts from the A/T. It comes out pretty fast at first (like as if you were doing an oil change), but it will slowly, constantly drip after about 10 minutes. Once you’re done with the draining, you fill it exactly with 2 quarts of Toyota T-IV ATF. Check the ATF level with the dipstick to get a good piece of mind. . .

For each drain and fill process (drain the ATF, refill with 2 quarts, drive around town for at least 5 min to mix the new and old ATF), here’s how much of the old ATF fluid remains (the GS400’s A/T capacity is 9 quarts):

Percentage Old AT Fluid Remaining after a ATF Drain and Refill Process, and susequent Drain and Refills
(1) 77.8%
(2) 60.5%
(3) 47.1%
(4) 36.6%
(5) 28.5%
(6) 22.1%
(7) 17.2%
(8) 13.4%
(9) 10.4%
(10) 8.1%

Basically, after 10 drain and refill processes (20 quarts of ATF total), you will still have approximately 8% of the old fluid left, which is pretty neglible. If you want essentially all of the old fluid out of the A/T in one step, then you’ll need to do a A/T flush procedure (moderate cost at Lexus dealerships or a rather challenging process for a DIY job as you don't have the macinery), but it does get all of the old fluid out.

From my standpoint, I think doing a drain and refill (as outlined above) 4 times is good enough for an initial start (36.6% old fluid left). Mind you, my fluid was a bit on the brown side (after 4 drain and refills, it’s a bit more pink, but some brown is still present since ~1/3 of the old fluid was still present). To get the dilutions of old fluid even further down, during each normal engine oil change, I’ll also change the A/T fluid for the next few times to get more fresh fluid in the A/T (changing the ATF is easier than changing engine oil as it doesn’t require a filter change). As the Toyota T-IV ATF is only $3.79/quart from a local Seattle dealership (Burien Toyota), it’s not too bad of an insurance policy to use. Once I eventually get the ATF to less than 10% old fluid, I’ll probably do a drain and refill once a year.

CHANGING THE AUTOMATIC TRANSMISSION FLUID (ATF drain and refill)

Tools required: 14mm socket and wrench, long funnel with a small ½” tip (can get these from Schucks for $2), oil drain catch pan and newspaper sheets to catch errant oil spills, 2 jack stands, new crush washer, 2 quarts Toyota T-IV ATF

NOTE: MAKE SURE THAT THE EXHAUST PIPES ARE NOT TOO HOT OR YOU WILL GET BURNED!!!

How to do it:

1) Chock (secure) the back wheels. Jack up the front of the car at the front jack points just behind the front wheels so you can get underneath it—do it for both sides.

2) Underneath the car, from the back of the front wheels two feet rearward, you’ll find the exhaust pipes join together into a “Y”. You’ll find a flat black pan just forward of the “Y” with a 14mm drain bolt head sticking out of it—that’s the ATF drain bolt. Place some newspaper and the oil drain catch pan underneath it, and remove the drain bolt to drain the ATF.

3) After about 10 minutes of draining, replace and securely install the drain bolt using a new crush washer. The ATF will still be coming out in a small drip stream—it’s OK, just replace the drain bolt.

4) In the engine bay, remove the ATF fluid level dipstick by twist unlocking it and pulling it straight out (it’s on the driver’s side of the engine). Place the tip of the funnel inside the exposed ATF fill hole, and slowly fill with 2 quarts Toyota T-IV ATF.

5) Replace the ATF dipstick and make sure that it’s in the lock position. Lower your car and remove the jack stands. Drive around for at least 5 minutes (making sure that your car shifts into all gears for a least a little bit) to mix up the old and new fluid.

6) Check the ATF level and add more fluid as necessary—don’t overfill. Check for leaks.

7) If doing another drain and refill process, repeat steps 1-6 again. You don’t need a new crush washer for each drain and refill, if you are doing a couple of them sequentially on the same day—just use a new one for the last drain and refill to ensure a leak-free seal.

Changing the ATF is very easy to do—if you can change your engine oil, you can change the ATF. If you are already jacking up your car for an oil change, why not drain and refill the A/T fluid as well at the same time (as like some others do as well)?

 

thanks for the detail explaination...i trust my mechanic, but now I have a good idea why it took him 20 qts

 

No problem.

Alternatively, if your mechanic didn't want to take the car down from the jack stands and expedite the drain and refill process, he COULD have done this Lexus method, but I would not do it as all four wheels are not off the ground:

(after refilling the transmission. . . instead of lowering the car and driving aroudn for 5 minutes on the road. . . )

"Start the engine and shift the shift lever into all positions from P to L position and then shift into P position."

Mechanics can do this as they have the hydraulic lifts to get ALL 4 wheels off the ground and are very secure. However, for us that just have 2 jack stands and lifting only the front wheels up, we risk a major accident by accidentally launching the car into the garage wall during the shift process described above. Hence why I only recommend lowering the car off jack stands and driving the car around for a bit to mix fully the new fluid with the old. If you just did a drain and refill without doing the above Lexus step or step 5) I outlined above, you'll just be draining new fluid that just got poured into the pan, so it's essential that you mix the new fluid fully with the old