Ls430 Gearbox Failure

[steve2006]

The radiator is a combined engine coolant and transmission fluid cooler acting as an intercooler in effect.

If you look at the very bottom of the radiator you will see the transmission cooler, it has 2 small diameter pipes emerging from it at the rear.

Fiting an after market cooler should be a matter of selecting a mounting position,disconnecting the original pipework and then fabricating new pipework and suitable connections.

Fair selection on amazon and eBay

http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=transmission+cooler

[The-Acre]

Thanks Steve, paranoid maybe, but if it's a reasonably straightforward job it surely makes sense to do it for peace of mind.

[ColinBarber]

the difficulty is finding a suitable position for the cooler so it gets air passing over it whilst moving. Ideally in front of the main rad, that way you also get air passing when stationary and the electric cooling fans come on.

[The-Acre]

I'll have a good look tomorrow. The problem of course is not knowing the exact size of a new part until it arrives. So would replacing the radiator work, they don't seem that expensive?

[ColinBarber]

It isn't the radiator that is failing, it is the oil cooling inside the bottom on the radiator that is getting a hole in it and allowing the pressurised water to enter it. Not really sure how this is happening if the correct Toyota coolant is always used and there is no air in the radiator to aid the corrosion.

It is therefore the oil cooler that needs to be replaced.

[The-Acre]

It isn't the radiator that is failing, it is the oil cooling inside the bottom on the radiator that is getting a hole in it and allowing the pressurised water to enter it. Not really sure how this is happening if the correct Toyota coolant is always used and there is no air in the radiator to aid the corrosion.

It is therefore the oil cooler that needs to be replaced.

Thanks Colin, I may have confused the issue a bit. I'm assuming the oil cooler part is integrated within the radiator, and is not changeable as a separate component, which is really why I asked if changing the rad would work. I had a good look today and there is plenty of space for a separate cooler, it doesn't even look that difficult. The problem of course is knowing what size cooler to get. The other alternative of course is to assume the problem won't occur and stop worrying!

[ColinBarber]

the oem radiator isn't a sealed unit, it comes apart and the oil cooler is accessible. Don't know if third party rads would be designed the same way.

The following is for the GS430 but similar concept.

[pheobe]

Hi

I can't be 100% sure regarding the coolant that was used but the vehicle had a fsh and I managed to get the Lexus dealership look up i'ts history it had a new rad fitted at some time in it's life before i purchased it no reason why was shown. So no obvious reason for failure.

The ATF cooler I fitted is working a treat, no problems so far done some lengthy motorway runs at the legal speeds of course

[pheobe]

Hi

Just had a look to se if I had any record of the size ofcooler I fitted but not to hand. I got mine of eBay there is a fair selection I think it was about an 8 row unit ,but as they are only really needed in hot climates or if towing any small unit should suffice.

[ColinBarber]

as they are only really needed in hot climates or if towing any small unit should suffice.

That is the recommendation in a normal situation, in addition to the standard oil cooler within the rad. With it removed ...

[The-Acre]

the oem radiator isn't a sealed unit, it comes apart and the oil cooler is accessible. Don't know if third party rads would be designed the same way.

The following is for the GS430 but similar concept.

Screen Shot 2014-07-17 at 20.02.15.png

Thanks Colin, presumably then the oil cooler is a replaceable part?

[The-Acre]

Hi

Just had a look to se if I had any record of the size ofcooler I fitted but not to hand. I got mine of ebay there is a fair selection I think it was about an 8 row unit ,but as they are only really needed in hot climates or if towing any small unit should suffice.

Eric, do you still have the same car, if so, is there any chance of posting a photo of the new cooler and its position? I'm sure it would be very helpful to all LS430 owners. Also, is it a job you did yourself, and how long did it take?

[ROYT]

I have heard of this failure before, would it not be possible for DIY owners

to reroute the trans fluid through an oil cooler and bypass the radiator altogether?

if i had a 430 i would have a go at this.

what do you think Steve?

Seems I posted too late already been done!!

[pheobe]

Hi Iam sorry just at the moment I have no means of producing a photo, but yes I do have the same car. The cooler is bolted to the alloy cross member infront of the rad with small right angle brackets that places it just below the cross member to the right of center,my cooler is about 10"wide *3" high* 2" deep. You need two right angle connectors and fittings to come down to 10mm for the pipes to connect to, one will be long enough but you will need to extend or as I did replace the other with a longer piece of pipe. The whole job once all parts were obtained took about two hours, bottom cover off to expose pipes.drilling the alloy cross member was by far the most time consuming you need one of those gizmoes that allows you to drill at right angles and the space in front of the rad is tight but it can be done, fit brackets to cooler and bolt in place ,if you have the car up on ramps when you take the original pipes of yoy should only lose a tea cup of ATF at most. I will try and sort some shots once I get my camera sorted.

|Eric

[The-Acre]

Hi Iam sorry just at the moment I have no means of producing a photo, but yes I do have the same car. The cooler is bolted to the alloy cross member infront of the rad with small right angle brackets that places it just below the cross member to the right of center,my cooler is about 10"wide *3" high* 2" deep. You need two right angle connectors and fittings to come down to 10mm for the pipes to connect to, one will be long enough but you will need to extend or as I did replace the other with a longer piece of pipe. The whole job once all parts were obtained took about two hours, bottom cover off to expose pipes.drilling the alloy cross member was by far the most time consuming you need one of those gizmoes that allows you to drill at right angles and the space in front of the rad is tight but it can be done, fit brackets to cooler and bolt in place ,if you have the car up on ramps when you take the original pipes of yoy should only lose a tea cup of ATF at most. I will try and sort some shots once I get my camera sorted.

|Eric

Thank you, I'm certainly going to give that a go. It may not turn out to be a problem, but after your tale of woe I think it would be a wise move. If you do manage to get some photos it would be appreciated. I'll leave it for a few weeks anyway. Am I right in saying that the bottom of the radiator doesn't need plugging afterwards?

[pheobe]

Hi

I connected the two pipe stubs on the rad together just in case the thing failed again this should stop the loss of all the coolant.

I am a bit paranoid after paying for a gearbox rebuild.

[The-Acre]

Hi

I connected the two pipe stubs on the rad together just in case the thing failed again this should stop the loss of all the coolant.

I am a bit paranoid after paying for a gearbox rebuild.

Excellent, thanks. When I do it I may try to get various photos in case it helps someone else in the future.