I was recently advised by a Lexus Service Rep to NOT flush the ATF in my 94 ES300. He stated that it is a risky procedure which could damage my transmission. I was wondering what the forum's opinion is on this topic. Personally, I would like to flush it, replace any screen\filter and start "new". I bought the car used and the ATF is shaded towards black. I do not notice any shifting issues.

Thanks.

 

Sometimes they don't want to do it because of the high mileage and service record of the vehicle, especially on the older FWD car. For some weird reason if the transmission is overdue for service and you flush it. Next thing you know you'll need a new tranny. This happened to one of guy in the shop before, he did the flush on a 93 ES with 130K and no service record, a week later the car come back with shifting problem and end up with a new tranny.

 

Whats involved in a tranny flush? they just drain the old tranny fluid and fill the resovoir with new? I dont see how this causes a problem. By the way, where does the differential in an SC300/400 draw its oil from?

 

The tranny flush is a complete flush, not just drain and fill. It's take about 14 qts of fluid vs 2 qts. You have to fill up the flush machine with 14 qts of tranny fluid and hook up one line to the (out) tranny cooler line and another line( in) back to the tranny. Then let the engine run at idle until the 14 qts has exchange into the tranny. The whole process will take about 1 hr to do it from the start.
The differential on the RWD( SC,GS,LS) got the fluid inside the diff housing. I mean the diff. itself filled up with differential fluid and you need to change it every 30K. The differential is closed housind designed, just like the engine, coolant, brake system, AC and many systems in the car. But some system got more parts involve(lines and hoses), but the diff. just has one housing and everything contained inside the housing. I hope this clarified you question.

 

The Lexus dealer did not provide this service to begin with. I wonder if it is all a liability issue ? I have a Toyota dealer that is willing to provide the service.

 

not all dealer can do a complete transmision flush, They have to have the trans-x equipment to do this.
do a search on this topic, you will find it has been discussed many time

I also posted instruction on how to do this at home for those who like the challenge on my website.
Personally, I paid my dealer to perform this service, If I am gonna spend $100 for oil, I am willing to spend another $100 to get it done properly, you don't do a complete flush very often anyway.


for example:
https://www.clublexus.com/forums/sho...+flush+machine
Anh

 

As part of the flushing procedure, they can run detergent through the transmission after the old fluid is flushed and before it is refilled with clean fluid. Sometimes the detergent can effect the internal seals if they are already deteriorated from poor maintenance which results in lack of pressure and the need for a rebuild.