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LS430 Transmission cooler question

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Hello Lexus friends, 

I'm new here and I'll make a proper introduction later on because I am full of love with the very best brand in the world.

I have read many topics on the tranny cooler problem design flaw but I still have some questions and I cant find the answer. Hoping you gentlemen could help me out.  


- Can I get rid of the (future) problem by just mounting a good quality trannycooler like Mocal or another brand? 

- If I mount this, do I use the original lines onto the new cooler or is it smarter to get rid of all the lines and renew everything. Every unesseserely connection is a future risk in my opinion. 

- Can somebody please show me with a picture what lines I should use to mount on the future tranny cooler. 

- Somewhere on this forum I found someone saying that the original cooler is located into the radiator itself. Do I need to shut off those insert lines into the radiator?

- Do I really need to mount a new radiator when I also mounted a new tranny cooler or can I be sure with just a tranny cooler? I want everything to be 100% safe for the future and I think Ill keep this car forever. 

- What size cooler would be the best? 

- Is it smart to take a thermostatic cooler?

- Do I directly need to fill up the transmission fluid and how can I do that? Or should I fill up the cooler before mounting everything together? Sounds attractive but it's not really precise. Another problem is that there is no dipstick with these type of transmissions.... Very scary. 

- Mounting this cooler; Solid or in rubbers? 

- Is it correct that the size of the ports should be for 10mm hoses? 



After almost 2 years of thinking and googling I thought I should go for it now so thats the reason of this topic. 

Many thanks for your help and info! 




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You should get a lot of advice on this. I'll tell you my experience. You are correct in thinking that the oil cooler is located inside the water radiator. I had the radiator/oil cooler changed by Lexus on it's last service. Many guys on here have done it themselves (I'm getting a bit long in the tooth) and it is, probably, best to get the actual Lexus radiator.

Refilling the automatic gearbox, properly, is NOT an easy task. On the US forum, they recommend going to an automatic transmission specialist.

There is a lot of info on t'internet - especially on this and the US forum.

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