Caseyjones

Hey all.

I have a 96 LS400 w/200k mi and since taking ownership I have been chasing a groan. I installed a new PS pump/flush with Dextron last year and It's now pretty smooth and quiet under the hood. There is still a groan under the car, it's most pronounced before operating temperature, the whine/groan will quiet down as operating temperature rises to normal but it never completely goes away. It is very easy to hear when cold, sounds like an old Ford PS pump.

I searched trans whine and decided that I should remove, clean and replace the trans strainer and top her off with the correct Toyota Type IV fluid (I have no service history on the trans so not sure what fluid is in it currently) I drop the pan and remove the strainer and it's pretty clean, very little anything in it and sure not enough to impede flow of fluid. The condition of the fluid is good, its nice and pink on the fingertip but in the drain pan its dark red, there was essentially no junk in the pan, all is pretty clean. All I can see that could be a problem are the cork gaskets on the strainer are rock hard, maybe they are failing to seal properly and causing cavitation? I'm not to confident that replacing the strainer/gaskets is going to clear it up so is there anything else I can check or do while the pan is off before the filter kit arrives?

Anything else that can cause a trans to whine other that a shot front pump/torq converter? I hear these transmissions are pretty bullet proof and it shifts/drives great. Could it do this if someone put in the wrong trans fluid? Anythin else that I can do to quiet this pig down, I need it to last me a few more years while I'm still in the USA. I love the hell out of this car but I'm not going to replace the trans.

Thanks for any tips on making it right again.

dicer

If there is a chance air can leak past that gasket then its going to make noise, it could be a combination of that gasket and low fluid level. Also any other seals that lead to pump intake. And could be a pump going out too.

Caseyjones

The fluid was uniform and it operated fine. The car is nice and appears to have been well cared for and no signs of abuse. I know these are very tough transmissions so I'm optimistic that the issue is a simple fix. Could the wrong fluid cause this?

fixmiester

The best way I know of to check the pump for drawing air is to put a piece of clear tubing in line with the Transmission cooler near the radiator. There is not much pressure in that line, so it's easy to see bubbles if the pump is drawing air. If no bubbles are visible as the engine is warming up, then it is highly unlikely that you have an air leak. You may have to get creative in how to make temporary connections, but again, it is a very low pressure line, used for a short time.

LsG86

To OP, I could be wrong but that whine you hear is coming from the transmission. Read the 1st post in this thread in the link below. Something about the planetary gear wearing out and once it wears out the transmission will go too. https://www.clublexus.com/forums/performance-and-maintenance/751720-sc400-transmission-whine-in-1st-gear-a340e.html.

dicer

Good catch, the OP really doesn't say if the noise is idling and not moving or driving. If its only when driving then yes a gearset could be on the way out.

UNCJD

Caseyjones, let us know what it turns out to be. Good luck.

Caseyjones

Thanks for all the responses.

I hear it easily while cold idling in park, its fairly pronounced while standing outside the car. When I drive I can still hear it inside at low speeds until it warms up, after a few miles it can not be heard from inside the car but still faintly while standing outside idling in park.

The trans gasket kit will arrive tomorrow, I think it's a long shot but I'll reassemble and hope that it magically fixes the issue. I will post back the results. Thanks guys!

LsG86

I hate to be the bearer of bad news, but your transmissions might be on its way out. How do I know? My car had developed that EXACT same whine noise you are experiencing about 3 months ago, well about 2 weeks ago my transmission finally went out on me at 189k miles. I thought it was catalytic converter but it was the transmission.

I am in the process of putting a used low mileage transmission in my car.

I highly suggest you have a qualified mechanic look at your car before things get wrost.

Caseyjones

This symptom jives perfectly with the clogged strainer issue. This has been going on for the year I have owned it and has not really gotten much worse, if at all. I was all excited when I dropped the pan and it was fairly clean, no junk and the strainer was clean, but then the reality that something else could be wrong quickly set in.

I'm hoping to be able to use this car for the next 3-5 years at which time I'll be retiring and moving to Baratok Nuevo, depending on election season I may opt to go early. I cant justify dropping the transmission on a car I will have to part with at some point in the not so distant future. I have not noticed to many threads about transmission failure on this forum so I'm still hoping that a new filter will do the trick. Is the pump a high failure item? Could the wrong fluid have done it, there are not many Lexus and no Lexus dealerships in this area, it is conceivable that an indie tech could have put effen Dextron in it instead of the right stuff, if that could eventually cause failure of this kind.

My ECU should get new caps but it is testing good right now, there is no way that an electronic malfunction could cause a pump to whine, is there?

EDIT: there was mention of a cat conv, can a failing cat emulate this sort of sound? Maybe thats why it's so hard to pinpoint with a stethoscope. I have had cats fail but never make a sound like that.

LsG86

I really hope I'm wrong about your car, but my car had developed a loud whine noise when I crank the engine form cold starts, once the engine got to operating temperature the whine noise would cease until next morning or next cold start. Right before the tranny went out, the whine noise got a littler louder and it could be slightly heard after the car warmed up.

My tranny gave out about 3-4 months after it developed the whine noise, YMMV, but hopefully yours don't give out.

Caseyjones

Ok, I had the pan and filter off for a couple days as I waited for parts. When I dropped the pan I got what I would guess was ~2qt out, it was still dripping slowly today but could I have lost another qt just from it sitting there w/o the pan? I ask because I have 3 qts back in the trans now and it's not even on the dipstick. At the end of 2 qts it was barely going into gear so I added the third and it goes through the gears fine.

Normally I would just keep adding until it came up on the dipstick but all the writeups were very clear about 2-ish qts. Not sure if something is amiss.

I checked the trans fluid a couple weeks before doing this and it was uniform hot idling in park after a drive. Maybe it was low the whole time and the dipstick picked up residual from the side of the dipstick tube and I misread it. I should know better, I have rebuilt a few C4 and C6 autos before but this is quite different.

Speculation mode off -/

Any wisdom appreciated.

dicer

96 I don't know. But a simple drain and not sitting for days is 2 quarts on Gen 1. I think it is a bit more on Gen 2.
That could have been the problem not enough in the beginning and the pump was sucking some air, a very slight over fill won't hurt a thing make sure its at temp and on flat ground in park and running to check it.
Did the noise go away? Oh and sitting for awhile lets the torque converter drain a bit so you will get some extra out that way.

Caseyjones

That must be it, I put the pan back on to wait for the parts to arrive and when I dropped it this morning there was probably another .5 or .75 qt back in it and I got showered when I let it down expecting it to be relatively empty.

I picked up 4 qts thinking I would have two more for the next train/fill that I will be doing with oil changes from now on. The noise was still there but started quieting down by the 3rd qt but then it was warming up to, so still not sure but I'm cautiously optimistic that the problem has been remedied. It is 85 deg today, how long should I let it idle before the trans is warm enough to use the HOT line on the dipstick?

EDIT: 4qts in and still not there.

dicer

Wow, is there a leak some place. That would make the noise low on fluid. It is the correct dip stick ?
Hot is after driving maybe 4 miles and engine up to operating temp, more driving if the climate is cooler.