LA4Mead

I think you're on track here, Engine. There are at least a couple issues at play here... Expectations are higher.

First, this vehicle was first sold in 1998 when many more people had internet access than those in the 80's and early 90's. I think expectations of consumer satisfaction are higher now.
Second, when people stretch their budgets to purchase a vehicle produced by Lexus that has a reputation for high-quality, reliability, and longevity, there may be an unspoken expectation that driveline components like the transmission will outlast 80's era Chryslers, Windstars, and others where there have been higher than average failure rates even on low mileage cars.
Third, I speculate the RX, especially the first models, seemed to lack the design for the use they were put in service for... Lots of city, idling with A/C waiting for kids, errands, low miles... A tougher trans meant a hit on fuel economy. When they replaced my crappy original trans with a new "updated" trans from Japan, I did lose a bit of fuel economy; a small price to pay if it means a trans that will endure.

engine89

Just to pick this scab a bit more, I would like to know if these failures occur more frequently in high heat areas such as Florida, Az, Cal, etc. and less in cooler northern states. If so I would be inclined to add an aftermarket trans cooler and lower the unit"s operating temp. and focus less on the condition of the fluid.

engine89

I was just looking at that trans cooler and I think I'm going to make some improvments. They have it stuffed in the passenger side wheel well with limited air circulation. One easy fix is to cut away the vents in the wheel well and add larger louvers.Also maybe cut away a bit from the bottom. A small fan may also be a possibility.

LA4Mead

I would... And I did both - as cheap insurance for a car I want to last (15 years now) . After the warrantee expired I also added an additional trans cooler. Following advice from a Lexus-trained head mechanic to keep the heat from being reabsorbed into the system, I placed it inline with the factory "tow package" cooler in the passenger side fenderwell. I used a high-efficiency, high-flow, thin design cooler so it fits between the plastic fender and the stock cooler. Then I used an exacto to cut larger and more cooling vents, and added a 4" computer cooling fan with a Hayden adjustable thermostat (and set it at a low temp). There isn't much room for a larger fan, but you might be able to fit a small motorcycle radiator fan instead of a computer fan. Yep, along with type IV fluid changes, I think it is easy, cheap insurance any DIY can perform.

engine89

I'm thinking of just cutting the bottom and adding an air scoop then cutting the wheel well and adding large louvers for max air flow. That should be enough for my NY climate.

gazi001

That would be a good idea? Good luck engine 89.