AaronE

Just noticed that my torque converter shudders when the lockup releases (i.e. the shift from lockup to open 4th). It feels sorta like going over very slight rumble strips, which is probably why I didn't notice it when I bought the car a couple weeks ago. It doesn't shudder when locking up, and seemsto be worse when starting up a slight incline when the car needs a bit more power.

Is this bad? Is my TC about to fall apart? Something I can test/check/fix?

Thanks,
-Aaron

1992 SC400

hemogoblin

The same exact thing started happening to me recently. Can anyone else shed light on this? I have an sc300.

sweetsc400

Same here, I was in denial until I came across this thread. I just kept saying to myself "it must be the road". Although it doesn't always do it, even under the same conditions (up hill with torque converter locked at low rpms).

How many miles do you two have on your SCs?

I would greatly appreciate any insight to this. Thanks.

Matt

Dominik

I have the same issue. Apparently this is the famous 'transmission shudder' that is caused by not using Toyota Type IV transmission oil in the tranny. Apparently a full flush and refill will resolve the issue and make gearchanges MUCH smoother...

mikefly

mine has just a occasional touch of shudder when lightly accelerating after coast

A friend had an Accura with very noticeable shudder and was told to drain and flush the trans 3 times
- it didn't work
try the drain and flush - nothing to lose- good luck

my 400 trans gives off a gear `mesh' noise (like two spur gears working with no oil)
which I only hear at low speeds in or out of OD. seems to come from the tranny,
but may be traveling from the diff?
anybody have any experience with that?

mike

AaronE

LOL, this was exactly me. It's GOTTA be the road... but alas, no.

So, just to clarify, this is ONLY from lockup to non-lockup ("virtual-5th" to 4th). The tranny and TC share oil? My understanding was that non-type-IV shudder was on all shifts, not just TC unlock. Oh, and by the way, my SC has 109,000mi on it, and the shifts are, if anything, too smooth.

sweetsc400

Here's my story:

I got my car with fairly high miles, but it was a one-owner always serviced on time at a Lexus dealership. It's a clean car. Upon picking it up, I decided I wanted to go through all the fluids and filters, though they didn't ALL need it. When it came to my tranny, it was WAY late and I had to drive the car the next day. So I was doing the refill and looked in the owner's manual to see that it called for T4. My friend (who is a mechanic) assured me DM3 tranny fluid was JUST FINE. So off I went. It shifted beautifully that night. The next day I got in it and couldn't make it out of my driveway it was slipping so bad. After kicking myself in the head for 3 hours, I went to Toyota and got T4. Drained and flushed the whole system, and filled with T4 while praying my transmission was still ok. It still shifts good, but I can't help attributing this shudder to my dumba$$ for putting non-T4 fluid it. I am probably one of the pickiest guys when it comes to critiquing how a car shifts (i.e. smoothness). My car's 1-2 shift seems to be a bit too pronounced. It was this way before my mishap as well. . . However, under moderate to full throttle it's imperceptible. I guess it's just normal wear. And the torque converter shudder is barely noticeable as well. It feels as though the engine is hesitating momentarily, or a bumpy road. Maybe a dragon tc is called for???

boredguy77

I have a TC for sale in the classified section.

Hermosa

He is talking about a SC300 not SC400. Most SC300 auto trannies need Dexron III and not Type IV tranny fluid like the SC400s. This is from the Lexus manuals.

Is the shudder the one at around 40mph?

My tranny also started to shudder more before it blew up.

On another note, my advice to people who go forced induction. Do not upgrade your tranny first with something like a TC. There is something to say about a transmission that has never been messed with. Similar to the same reason never to buy a rebuilt 6sp getrag. The original non-rebuilds last longer according to alot of folks who have used them. Let your tranny blow up and then upgrade. No use wasting money on double labor. Just save up for a built tranny.

Hermosa

Holy smoke Aaron, if you have the five speed auto then you have a 98+. That's a heap of miles you have there.

AaronE

Nope, by "virtual-5th" I meant the act of locking up the torque converter which is somewhat of a "poor-man's 5th". I have a 1992 SC400...

So do we have any idea what causes the shudder in the torque converter? Again, the problem I have is not in the gearbox, but in the TC, and only on unlocking, not on locking. I'm kinda hesitant to bother flushing the whole tranny if there's no point...

mikefly

hey hermosa!
is the shuidder at 40 you're talking about like this:
level road,no load constant speed (around1500 RPM - 40MPH), and it feels like
an ignition miss?
other than this the car is smooth
maybe I've been looking for the wrong problem.
mike

hemogoblin

Hermosa, do you have a 300 or 400 ?

Hermosa

The 400 has no shudder, the 300 had shudder before it failed.

Nomis

Has anyone had any luck in solving this issue? I don't know how you guys just "live with it". Per suggestions found on the site, I've changed both engine mounts, transmission mount, flushed with Toyota Type IV fluid - made sure not to overfill, and even had new tires put on. And after all of this it still shudders when the torque converter locks up at 38-42 mph. AAAARRRGGGHHHH, it's a frigging Lexus and it feels like crap when it starts shuddering.

Is there anyway to install a TCC lockup override switch? I know of a way to do it for a TH-700R trans.
Has anyone had the dealer reprogram the ECU for a higher lockup speed?
I've thought about replacing the TCC, but someone on the board said they swapped in a Dragon TCC - and the problem is still there. This sucks.