Is this a good idea?

[royr]

I have been using Dextron III and changing the trans fuid every 30,000 miles since I bough my 2000 LC New. I am considering changing over to Royal Purple synthetic trans fuild with a full flush. My Toyota dealer said it is a real bad idea and it would cause the trans to slip and fail using any fluid other than Dextron III, said synthetics are a big No No in a high milage transmission (I have 74,000 miles) and would not perform the service. Is this somthing I should do myself? Does anyone have experience with this?

 

[Jim_Chow]

Can't say, I only use Toyota brand type-IV (I think made by mobil) and change it at 30K intervals (full exchange using the machine at the ATF cooler lines). I thought about using Amsoi since it says it's T-IV compatible, but it would still cost $100 in labor plus $200+ for two 2.5 gal containers, which amounts to twice the cost as having the dealer use Toyota brand T-IV. So I'd have to run the synthetic twice as long (60K mi) just to break even. Plus since my vehicle is under warranty, if the tranny fails and it was serviced by Toyota within the recommended interval using their fluid, Lexus/Toyota can't say it was the third-party brand ATF that did the tranny in. I also get more peace of mind knowing the ATF was changed at 30K intervals rather than 60K intervals.

 

[drsales]

I went with mobil-1 in both of my trucks and everything is fine. No problems at all. Your decision on either way to do. My mechanic agrees. You could do a slow change over. Just drain the trans pan and replace with synthetic. Adds a few quarts evry change. Thats what I have done with the 80. I am at about 70% synthetic.

 

[LXPearl]

I am taking the slow approach, drain and fill several times. Initially I started with Mobil 1 ATF and have switched to Redline D4ATF (rated for Dextron III). I like the synthetic performance, especially the Redline. Since the Redline is rated for Dextron, I am quite comfortable with it.