Transmission pan

shanra · May 26, 2017

I need to reseal this I have the correct Loctite 5660 just wondering do I need to just go around the inside of the pan mating surface and how thick does it need to be laid on. I took this off to change strainer and clean pan and boy do I wish I hadn't the filler tube was rusted where it meets dipstick tube so had to take the whole of it off and free it up, and now having trouble lining it up so as to get the right angle for the pan to go on without sealant fouling anything inside the transmission.

Newbie1 · May 26, 2017

I just had my mechanic do what you've done and it is now leaking all over my drive. Watching this thread with interest.

ambermarine · May 26, 2017

I have posted several times on removing the pan on the transmission I was vehemently against interfering with this part of the transmission in any way.

The requirement to remove it is not there as the filter will not require any renewal or cleaning it is there to pick up any swarf or debris during the running in period and is not going to get clogged up .

It is also impossible to seal unless the box as been drained and flushed then dried as the transmission fluid will destroy the seal as soon as it is applied.

The factory setting period for the seal is judged as a dry application and to that end there cannot be a seal made if there is any fluid in the box ,which there is because when the pan is removed there is still two thirds of the fluid still in the box and torque converter.

I have to say it but you will now likely have to live with a leaking seal for the rest of the life of the car.

Newbie1 · May 26, 2017

Oh bugger.

shanra · May 26, 2017

I did this before on my Soarer and it didn't leak whilst I had it the problem is it that whas so long ago I cannot remember how I applied the sealant. I must say the strainer was not that dirty but the pan had turned light grey and there were some small specks of metal so I think cleaning the pan may well turn out to be a good thing. If I had another LS 400 I must say I wouldn't bother (if it was a filter in there then I would) but the strainer is passing fluid through a metal gauze. The sealant will be on overnight before a refill and getting it to keep the seal I believe is in the preparation of the surfaces and as long as you don't let any fluid drip on the sealant whilst fitting I cannot see why it would not hold.

harrylime · May 26, 2017

I had this seal replaced by Lexus Sheffield, due to a minor leak. No problems since, but it took quite a bit longer than they expected.

shanra · May 28, 2017

Well I now know this sealant has to be put on the centre of the pan and around the inside of the bolt holes but it's the thickness that's needed that I don't know. I know it's crucial to get it right as you don't want any sealant in the pan. Anybody?

harrylime · May 30, 2017

Not an LS, but the same technique, I would have thought -

shanra · May 30, 2017

Hi Hugh thanks for that but I have done it, it took me ages to find all the relative information and I'll do a write up when I have some time. I had looked at part of the LS 400 repair manual and it seemed to give me two different guides as to the width of the sealant bead which completely threw me, I ended up going with 2-3 mm as it made most sense.

Newbie1 · May 30, 2017

Good info here. I have ordered Three Bond 1281 sealant which is used by Toyota. Not cheap but then quality never is.

39buss · May 30, 2017

If the auto oil pan is steel then why not stick a couple of button type magnets on it and this will attract any metal swarf and stop it from being sucked through the gearbox. Auto box pans I've dropped had magnets inside and they all had a small pyramid of swarf on them. Drain the oil, top it up, use it for a week, do the same again and you should have a good percentage of fresh oil dilution. If its not leaking, don't give yourself the hassle.

Newbie1 · July 27, 2017

Quick thread revival after I had an ATF leak after I had the LS400's transmission pan dropped and ATF fluid and filter changed etc. The mechanic removed and stripped the pan down and resealed with the Toyota approved Three Bond 1281 sealant. No more leak.

shanra · April 16, 2018

The seal is holding on my transmission, as I said before it is in the preparation of the two surfaces and then torquing the bolts correctly and tightening in the right sequence. I wouldn't bother taking off the pan though unless you have some problems with your transmission.