redgs400

For the last couple of months, I've heard a crackling noise which sounds like it's coming from the transmission area or my '99 GS400. The noise is best described as a sharp crackling/popping sound like I'm driving on gravel.

- Sound only occurs while accelerating from a dead stop to around 15 - 20 mph.

- I must come to a complete stop for the noise to occur; it will not occur from a "rolling stop"

- Changing to my snow tires/wheels does not eliminate the noise (i.e. not bad tires).

- Putting the transmission into Snow Mode will not eliminate the noise

- The noise will occur when the engine is cold or warmed-up.

- Noise will not occur if, at a dead stop, I put the transmission in Neutral and rev' up the engine
to 2500 rpm or so (i.e. not engine)

Anyone have any ideas. If it's the transmission, I'm thinking it's either 1st gear or the torque converter. I'm going to empty out the car and make sure it's not anything loose in the interior. I also want to do some other testing, like holding it in 1st gear, to try to eliminate possibilities.

I don't punish my GS', so I'm surprised that this occurred. I have around 40k on the odometer.

It sounds EXPENSIVE

bitkahuna

iTrader: (20)

This reminds me of the old trick on wheels with hub caps. You put a few stones in the hub cap. When the car is going along, no sound. From a standstill, there's a rattling noise as the stones haven't been forced to the edges yet and it will drive the driver crazy.

I know we don't have hub caps, but maybe it's something to do with your wheels? Loose balance weight?

redgs400

Thanks for the theory, but I believe I've eliminated that possibility.

I don't believe the issue is tire/wheel-related, as I spent some time yesterday swapping on my snow tires/wheels, which are a completely independent set.

I had considered that it might have been broken belts in the tires; hence the temporary swap to test this theory.

I have an appointment to bring it in to Lexus of Portland this Wednesday to have them take a crack (no pun intended) at it. I just would like to have done as much elimination as possible beforehand--since my time is a lot less expensive than their time :-)

redgs400

Thanks for the theory, but I believe I've eliminated that possibility.

I don't believe the issue is tire/wheel-related, as I spent some time yesterday swapping on my snow tires/wheels, which are a completely independent set.

I had considered that it might have been broken belts in the tires; hence the temporary swap to test this theory.

I have an appointment to bring it in to Lexus of Portland this Wednesday to have them take a crack (no pun intended) at it. I just would like to have done as much elimination as possible beforehand--since my time is a lot less expensive than their time :-)

kvoman

Isn't the Lexus' warranty on Powertrain 6 years or 70k miles (http://www.lexus.com/models/warranty...owertrain.html)? If you have only 40k miles and your car is a '99, it should still be under warranty, unless it was bought in June 98. The warranty goes with the car, unless you bought your car from a person who bought it as a CPO from Lexus, in that case, the warranty may not transfer. If you bought it from someone that bought it as a CPO, you may want to read the fine prints on the warranty items, someone here said transmission is covered under original warranty but others have said differently.

redgs400

Hmmm... Thanks for pointing out the warranty! I need to dig out the owner information in the glovebox and
verify that. I bought the vehicle, new, in May of '99. And I'm not ready to part with it yet

I'm bringing it into Lexus of Portland first thing tomorrow morning. But I'm going to empty everything out of it tonight and make sure that it's not a "user stupid" error, like one of my son's toys rolling around under the seat

Gonna see if I can get one of their RX330 loaners... my wife is interested in the hybrid version, and it would be an ideal chance to try one out without a sales rep' in the car with us. I'll let the forum know the prognosis.

kvoman

You're golden with the warranty.

We use hybrid vehicles at work and I wouldn't recommend it unless you use it around town only. It gets very interesting trying to merge on the freeway and passing takes a whole lot pf planning. Car-N-Driver did a recent comparo between the Honda Civic and the Civic Hybrid and their conclusion was you'd have to drive the hybrid for a very long time to make up the additional cost difference between it and the regular Civic and they didn't like the fact that the hybrid didn't have the power to climb hills, etc. Check out their article for more information.

Try the hybrid with people and gears just as if you're heading for a ski trip or a camping trip to see if that is what you can live with in terms of acceleration, power, etc.

redgs400

I brought my GS4' into Lexus of Portland yesterday morning, and the service advisor decided (wisely) that it would be best for one of their technicians to take a test drive with me. So we headed off and tried to reproduce the problem while winding through the hilly residential area near the dealership, and (of course) the crackling sound didn't appear. I realized that the worse noise came after about a 40+ mph run, so we headed out onto the main road in front of the dealership, and SUCCESS: the tech' and I heard the crackling noise reappear.

After asking me a few other questions, he said that he believed that the culprit was air in the cooling system, which was causing noise to come from the heater core in the dashboard. He said that he had troubleshot a very similar problem in the past: after running at faster speeds, noise from the heater core when accelerating.

So they flushed the system once, test drove it, but still heard the noise. So they flushed it for a half hour, and test drove it again, and voila: no more crackling noise. On my way home and this morning's commute, I haven't heard the sound again. So it sounds like "case closed" to me.

BTW they only had four RX330 loaners, and I was unable to get one, so I ended up with a '02 RX300 instead...

Thanks for the suggestions! Maybe it's easier to post a sound clip next time

///MDex

What about an explanation as to HOW air got into the cooling system?

redgs400

Not too long ago, Lexus of Portland tried to troubleshoot my low-idle issue, but in the process, the throttle servo motor died. They ended up replacing the entire throttle body assembly which, according to the tech', may have involved draining and refilling the cooling system.

It's believed that during this, air got into the cooling system.

So it looked like a service-induced issue.

LofP didn't charge me to get the air purged out. However a half hour of idling to purge the system did take its toll on my gas consumption for this tankful