Automatic oil leak

[WGB]

My 6.9 is largely "oil drip free" on the garage floor with the exception of a 5 cent piece sized drip of red Automatic trans fluid which appears during it's 5 to 7 day lay-over between drives.

The automatic was serviced last year by "The Star Shop" in Perth with a filter and fluid change.

Recently it spent 2 weeks sitting on my hoist while I was waiting for some suspension parts to arrive and while it was sitting there it dripped about 10mls of automatic fluid onto the floor.

On the hoist the car was sitting in a "Bum-down" attitude as opposed to the more normal "Bum sightly up in the air" position it normally runs and settles into after a few days.

Since returning the car to it's wheels the floor has remained totally clean with no drips whatsoever.

On careful inspection the oil seemed to be coming from the right rear of the auto and the vacuum modulator had some oil dripping from it (?Around it). It did not appear to be leaking from the pan gasket area and the torque (7nm) on the pan bolts was correct. Rear seal is dry as is the torque converter.

I have not done a hot fluid level check to make sure it is not overfilled and automatics are the one part of a car that are largely left well alone by me but I have heard somewhere that a vacuum modulator can fail and cause a fluid leak or worse - allow oil to be sucked into the engine unnoticed.

I would imagine if they fail to this extent that it would cause the shift quality to become rough - which is definitely not the case.

Opinions would be gratefully accepted.

Bill

 

[Styria]

Hi Bill, non-use of a car certainly encourages oil leaks, and in your case with a five to seven day lay-off period, to have this small amount of leakage is quite remarkable and can just about be ignored.

The thread of the Modulator valve should be thread-smeared prior to installation and this may well be your source of the small leak. You can normally loose up to about 1.0 to 1.5 litres of ATF before the transmission starts slipping - not advisable, though. Regards, Styria

 

[WGB]

Styria - What do you use as a "Thread smear" and does it just thread in and out with no real problem or is there a procedure for removing and replacing it.

I will check in the manual but thinking about it the thread of the valve is where the leak appears to be coming from.

Bill

 

[Styria]

Hi Bill, selleys, loctite or THREE BOND all make good products, but just make sure that the stuff doesn't seal too well by going hard. Your bearing place should be able to advise of the most suitable productyou need a product that not only seals, but also remains fairly soft.

I also had a look at a box today-there is absolutely no other fitting in that area above the modulator valve where you'd get a leak, therefore it has to be the valve. Regards, Styria

 

[Des]

Hi Bill, non-use of a car certainly encourages oil leaks, and in your case with a five to seven day lay-off period, to have this small amount of leakage is quite remarkable and can just about be ignored

Dear Styria
Is it enough to start the car up and run it once a week to avoid this, for say 10 mins?

There is probably people here like myself that have cars that just sit around a lot of their life without much use, but would like to ensure they stay in the best condition possible, sure car parts wear out, just thinking about what is in the best interests for the car.

I have spoken in the past about this matter to my mechanic and he says that a car should be driven once a week for 20k's to get it to warm up and keep everything lubricated, maybe this is getting offtopic?
Just noticed your comment on the trans leaking


thanks
Des