I bought the car 99 gs300 with 57K on it 4months ago. The mechanic at the dealership I bought it from said to not change the Trans Fluid on Lexus or Toyota or you will ruin the Transmission. In the past I have also heard that if the Transmission fluid was never changed and you try to change it with high milees that the new flush will damage the clutch material in the transmission. I dont know the history on my car but I want the best for my BeBe. What do I do.

Also If I do the machine Trans Flush, is that harder on the Trans than just draining it and refilling? Do the machine flush also flush the Differential? And finally I know the best Trans fluid is the Amsoil Universal but what Viscosity?

 

this is what lexus say about tranny fluid: only change it when necessary.
check the fluid color...if it's dark brown, then you should change it.

no auto manufacturer recommends machine flush for a good reason. you risk damaging the delicate parts inside the tranny.

if your tranny fluid is really really dark, just change it, and on the next oil change, change the tranny fluid again. this works just as well flushing.

 

Well a full machine flush for a tranny that has really bad oil might be a shock to the whole system. It might dislodge some big chunks of sludge and plug something up. I'd just do drain and refills every oil change to slowly clean the system out and slowly dissolve the sludge in there.

Also, I think the new Toyota T-IV fluid is synthetic(used ever since like 02+ or so). In the manual it says to change it every 100-120k miles or so. I drive pretty hard and managed to have dark...almost black transmission fluid at 20k miles! lol

 

If done with the T-tech machine it will cause no harm as no chemicals are utilized. Here is the unit http://www.ntxtools.com/transmission/soltt200.htm
Lexus dealerships use the drain and refill method which accomplishes nothing. I compare it to removing 1 quart of water from your dirty fishtank and pouring 1 quart of clean water back in the tank. The tank will still be filthy.

 

That's why you want to do a few intervals, not just one. Slowly introduce new fluid....

 

are you ok buddy? you forgot to suggest what kind of trans fluid he should use.



personally I'd do a drain/refill along with at least the next 3 or so oil changes.

 

When I got my car, the first thing I did was machine flush it. The only machine I would use is one that utilizes the trans's own pump system. The machine catches the fluid as the trans pushes it out to the cooler and the machine substitutes new fluid returning under the same pressure. You get the whole thing flushed including the torque converter.

The drain and fill is good if the fluid isn't too bad. I have never heard of a Lexus/Toyota tranny dying after a flush because the fluid was too dirty, that's more of a Ford thing, Mazda 626's with the Ford trans used to do that too.

Only fluid that should be used is the Toyota type T-4. It actually has been around for a while, the RX300's used it also. I have replaced my share of those trans because people used a "compatible" fluid or and additive that change the dextron to T-4.

Lastly, no the machine does not also change the diff fluid. That is separate and will need to be changed at diff intervals. I have heard people talk about using some purple synthetic fluid for the diff though.

Hope this helps.

-Bill

 

The Type-IV fluid is made by Exxon Mobil. Personally, I also recommend the Amsoil ATF (which I can't get down here) as it is a superior fluid. However, I generally only recommend a flush in cases where one has silvery/pinkish fluid (full of worn material) to thoroughly get it cleaned out. If the tranny fluid is cooked, doesn't smell sweet and is dark, drain and fill it at least once first before even attempting a flush.