92 Ls400 Transmission Shudder

[sv7887]

Hi everyone,

This morning I took my 92 LS out for a drive. I noticed when driving at 40 MPH the transmission shuddered for a few seconds when I stepped on the gas. It's done this maybe once or twice before, but it doesn't happen on a regular basis. Time for some new fluid maybe?

The car has 99,300 miles on it, and had the trans fluid changed (5 quart pan drop) at 84,300 (during 90K service) over 2 yrs ago. I called the Lexus dealer to schedule the car for a trans fluid change and oil change.

The car has had a lot of work done recently. I recently had the P/S rack, high pressure hose, upper control arms, fan clutch, thermostat, Stabilizer Bar Bushings, Battery, Brakes all around replaced. The timing belt, water pump, ball joints, P/S pump were all done at 84K. I just had all four tires replaced with Bridgestone Turanza LS-V's and aligned properly.

As the car nears 100K what else should I have looked at/done? I'm giving them the car on Wednesday and they'll keep it until Friday. The car only gets driven once a week so I'm wondering whether it needs any special attention. I mentioned the Transmission Filter and Fuel Filter but they claim it's "Lifetime" That seems to be the Lexus party line...

Thanks!

Sam

[lexus400]

level is good ?

[sv7887]

level is good ?

I'll have to check the car again to make sure, but I'm pretty sure the fluid level is okay. There is no trace of leaks or anything. The car was checked over about 5 months ago by another Lexus dealer and they didn't tell me anything about the transmission.

I'm wondering if the shuddering is a symptom of older fluid. It has been 2 yrs since the last change. The car does sit in the garage alot.

I'll see what the Lexus dealer says on Wednesday. Can you guys think of anything else I should be paying attention to since it's around 100k?

Thanks!

Sam

[nc211]

Sam, how about the rear differential fluid? Have you replaced it lately, or checked that it's at the proper level? You could have felt a little kick-back in the rear differential that would run up the prop shaft and make you think it was in the transmission...

[AussiLS400]

Broken tranny mount maybe?

[Leadfoot]

I noticed when driving at 40 MPH the transmission shuddered for a few seconds when I stepped on the gas. It's done this maybe once or twice before, but it doesn't happen on a regular basis. Time for some new fluid maybe?

Hi Sam, what is happening is not uncommon and is not necessarily a problem either. Below is the toyota Technical service bulletin for our year, mines a 92 as well. They released this because of customers giving them "feedback" on the vibration. It feels like you have driven over a small patch of ripple strip right? Mine only does it when I have been cruising at 1800rpm and accelerate mildly. If I stamp it it never happens, gently never provokes it either. I cannot reproduce it at will, it is only when conditions are "suitable". I think gas quality may have a part to play too.

Anyway here is the word from the horses mouth.....

"ENGINE

EG92–002

OCTOBER 09, 1992

ALL MODELS

ENGINE PING REFERENCES IN OWNER’S MANUAL Page 1 of 1

Under certain driving conditions, minor engine ping, also referred to as “spark knock,” is common

for high compression engines such as those used in all Lexus models. Do not hesitate

to inform customers of the following information included in their Lexus Owner’s Manual:

This statement is included in all Lexus Owner’s Manuals on the following pages:

MODEL YEAR PAGE

ES 250 1990 165

ES 250 1991 171

ES 300 1992 165

ES 300 1993 170

LS 400 1990 166

LS 400 1991 166

LS 400 1992 172

LS 400 1993 192

SC 400 1992 170

SC 400/SC 300 1992 170

SC 400/SC 300 1993 186

Because all Lexus models have knock sensors, the following question may arise:

Q) When I hear knocking, does it mean that the knock sensors are not working

correctly?

A) Engine control systems with knock sensors operate by modifying ignition timing

when knocking is detected.

In other words, knocking must be present before the

control system acts to modify the timing. This is usually noticeable by a short duration

of a light knocking noise and is not cause for concern.

“If your engine knocks...

If you detect heavy knocking, even when using the

recommended fuel, or if you hear steady knocking

while holding a steady speed on level roads, consult

your Lexus dealer.

However, now and then, you may notice light knocking

for a short time while accelerating or driving up hills.

This is no cause for concern.”

Since yours sits around alot I bet the gas in your tank is not the best quality anymore. Go for a big drive and run it nearly empty then fill up with the highest octane gas you can find. My 0.02C says its poor gas quality.

That is exactly what happens in mine, and I bet yours is no different. It just the ECU working the best timing point out, and it happens to be around 1800rpm 40~50mph typically. Has been happening to me for a year now (crappy UK fuel!) and has not gotten any worse.

These cars can make you a bit of a perfectionist (wouldn't you agree NC211?) which is why toyota had to put out the TSB.

Hope this helps,

Cheers,

Leadfoot.

[sv7887]

Thanks everyone for all your help!

The dealer did a trans fluid drain and refill and it shifts great now...This time the bill wasn't bad, $175..the cheapest visit I've had in a long time...

I also got a ride in the ES350. The center console looks really cool, but the dash material looks a bit cheap, and the absence of the wood (compared to the ES330) is quite noticeable. The exterior is much better looking in person.

-Sam

[sonyman]

40MPH is when the torque converter locks up. First generation LS's and SC's are especially prone to shuddering when this occurs if the fluid is worn out. On a '92 I'd seriously consider taking it elsewhere than the dealership next time however. The last time I had a drain and fill performed my mechanic only charged me for the fluid since I was getting an oil change done at the same time. That's the best time to do it since the car is already lifted.

Scott