jcorredor

Hi guys,
I use my 2000 rx300 to drive up very steep hills to my mountain cabin. Ever since I got it (with 40,000 miles) it's had a bad transitory transmission vibration while going through about 2300 rpm. Once it gets up to 2400 the vibration is gone. The guy I bought it from says "they all have it". On a flat road it's there too but you can hardly feel it; it's only bad on a really steep grade. I'm up to 87,500 miles and still running. What can I do about it?

Lex2000TL

I would check engine and transmission mounts.

Lexmex

I'd try this again with a full tank and the vehicle loaded (like 4 people in the vehicle) and see if you notice it. I haven't ever noticed what you describe, but as mentioned mounts and shocks can go bad.

Are you noticing this also when the gears are shifting?

What mph are you at when you notice this?

rx300s415

I have the same exact problem as jcorredor. Two of my friends with the same vehicle (2001 RX300) experience the same issue. Even on flat grounds I notice the "shakiness." For example, I leave a stop sign. The car shifts into second. and at about 2300rpm the vehicle seems to struggle and vibrate a lot. After hitting about 2500rpm, the vibration goes away and the car sounds a lot smoother. When the dealership recently put dino oil in my vehicle, I noticed the vibrations were MUCH harder. My car, ever since 80,000 miles, has been using fully synthetic oil. After switching back to fully synthetic, I noticed the vibrations were calmed. I'm planning to do the AutoRX treatment this Summer, maybe this will change things. I wouldn't be surprised if the problem were some mounts going bad though.

gcrim21

I have always been told once you fill an engine with synthetic motor oil you should never go back to dino. ?????

jcorredor

To answer LexMex's input, I travel fully loaded up the mountain so it's usually in 1st gear when it's worst but, like rx300s415 says, you can also (barely) feel it in 2nd on flat ground; just as long as your going through 2300 rpm. a lot of rx300's seem to do this. I'll check all mounts ....

Lexmex

I will be back in mexico later tonight and can check this when I go out as I have several steep hills by where I live. To my knowledge I have never experienced what you describe. I plan also to change out my shocks on Saturday so that will further uncover any possible tranny movement should I detect anything.

jcorredor

Thanks lexmex, have a safe trip home.
jc

rx300s415

Ah, unfortunately, good to know others have this...so it's not a personal issue with my car. haha.

Lexmex

There is a sound I notice at when going up a hill but that is intake related sound. I didn't notice anything on two steep hills in the neighborhood that I live in, one by the University here and and other just by my apartment. There is another one by my uncle's that is steeper and I can give it a go on Saturday (probably after I finish with the shocks).

When you are going up the hill/mountain, are you flooring it, half way down or 1/4 way down on the accelerator?

Lexmex

I now have KYB GR-2 shocks on my RX300 (thread coming up shortly), and I tried this test again on the steep hill near my uncles, but I sensed no vibration, just regular intake noise that I would normally hear when going up a hill or incline.

jcorredor

So I just got back from the mountain cabin; travelled fully loaded, I've got to floor it in first on those steep grades. Shaky as always but now seems to be between 2500 and 2700. A friend mentioned the shaft bearing as a possible culprit...?

Lexmex

If you have a bad input shaft bearing in the tranny you'd be hearing other things at all times. About how much of angle in degrees is this grade that you are going up on? I can find steeper stuff around here to test my RX again on.

For instance, in Toluca west of here, I've got this 15,000 foot mountain called the Nevado de Toluca, an extinct volcano you can drive into the crater, but we've also got some really steep areas by my apartment building I could try as well.

Lexmex

Let me also add a side note on something I have been playing around with. I have removed the hypervoltage cable that I used to attach from the negative cable of my battery to the tranny and instead have attached it to the top of the tranny (16 mm big bronze bolt) to the sanded off point on the upper right (an old airbox hole, 10 mm). There is another area on the top of the transmission (I think a 12 or 14 mm bolt) that I also want to add another cable. I have been studying since my tranny work, about the interconnection of tranny function and grounding wires, mainly shifting I know from working at my uncle's shop that on trannies with bad or frayed grounding there can be some minor shifting issues. I will keep you all posted on this.

jcorredor

I wouldn't care to guess an angle on the grades there but my kid's friends keep overheating their cars going up that route. Nevado de Toluca looks pretty impressive. If yours is going to do the tranny shake anywhere, that's the place. My cabin is at 1,000 m altitude, I travel up from the coast.
I'm beginning to suspect some RX's do it and some don't. rx300s415: no it's not just a personal issue, looks like some of us are unlucky. But then again, I've been driving it 40K miles now and nothing has broken.