My wife's 2003 RX 300 began slipping real badly between 2nd and 3rd gears tonight. This is intermittent, but frequent. The remaining shifts are smooth. It doesn't whine or clunk, just revs freely between those shifts and won't find 3rd gear. The car has been driving perfectly since we bought it at 85k.

I checked the fluid and the level is at the very top of the hot and is still pretty pink.

I have changed the ATF at 98k, 108k, and now it has 118k on it. I have used Mobil 1 ATF. I've always found a little more metallic debris on the pan magnets in the RX than the ES, but the last time I dropped the pan the two magnets did not look aweful. No large metal chunks in the pan.

It feels like the transissions swan song. Tonight I'll pull the battery cable to try and reset things, but don't expect that to work.

Options?

Rebuild vs used trans? I would favor a rebuild given the track record of these transmissions.

Price?

Any good/cheap places in north Texas?

Any and all advice greatly appreciated.

 

I am new to Lexus but I have heard stories about a faulty knock sensor in the motor that could be a potential gremlin causing the issue

 

I disconnected the negative battery cable and cleared the ECU codes. Worked like a dream after that.

 

That's good news most of the reported transmission woes seem to afflict the 1999 and 2000 models, supposedly after 2001 it's much less common.

My co-workers 2000 died at 100,000 miles a couple of weeks ago.

 

I'm no expert, but I've been told to use ONLY type IV (type 4) fluid in the RX300, specifically not Dextron/Mercron that generally works in most other auto trans, even if sythetic. Most lube shops only carry the new Dex/Merc product and use an additive to simulate type IV characteristics, which I was told leads to problems. I'd try it with type IV and see if you still have problems. Fortunately, it doesn't sound like you have problems with the fluid burning, so good luck!

As your common sense has already told you, I'd steer clear of used RX transmissions if it comes to rebuild/replace. I think that's asking for trouble.