My Sons Lexus ES300 is Sick

Since the transmission fluid is dark — and appears low — and since the tranny is going in and out of gear if you put pressure on the accelerator, your best course of action is to send the old transmission packing and install a used on. Of course, there might be good parts inside the current transmission, however, that is where those parts should stay as they have been in use for quite some time and are part of the transmission that is giving the ES300 fits.

The key clue, aside from the transmission’s performance, is the transmission fluid. Since it has not been changed in over 200,000 miles and since it is dark, it is likely the problem is being covered up to a degree by the fluid. The issue could be in the gearing, the clutch packs and bands or it might involve, and may have started with, a plugged transmission filter. The gears could actually be rubbing against one another, as could the parts of the clutch packs and/or the bands. If any of these devices are rubbing, they are shedding small particles of metal into the fluid at all times which can build up and help to turn the transmission fluid dark. If the filter is plugged, solids are not being strained from the transmission fluid and are being allowed to build up. Over time, the plugged filter can cause the fluid to darken.

Another cause is overheating and burning. Because of the way transmission is manufactured, it is susceptible to burning from overheating. Tranny fluid is made to operate properly within a narrow range of temperature at or near 200-degrees-Farenheit. If the fluid is overheated and run for any length of time, it will actually burn and degrade. You can often smell the burning by using the dipstick and sniffing the fluid. If the fluid is dark and smells burnt, you have little choice but to replace the transmission.

The price of the replacement, with labor, will be about $3,500. Some would argue that it is best to have your transmission replaced at the dealer where you purchased the vehicle as, they also argue, the dealer knows the car. Often, though, that really isn’t the case as the technician working on the transmission could be relatively new and could still be learning the product line. In this case, it is best to bring your ES300 to an independent transmission specialist as the technicians are likely to be certified by the National Institute of Automotive Service Excellence (NIASE). Since the work they do is primarily on transmissions, you can be sure that they know their subject and will give you excellent service.