Turbo 400 leak

[RAEME]

Hi all.
I have been trying to sort out a leak on my 400. While the van sits the box leaks somedays some not.
I put it up on the hoist yesterday and it's wet around the pan gasket and the round vacuum cyl on the RH side. It appears to be leaking thru the gasket!! This gasket is new hasn't moved since been fitted. I also removed the vacuum cyl last year and replaced the Oring. So today I removed and replaced the gasket and Oring again, this time I used ultra blue on the gasket. I've left it on the hoist with no oil, will fill tomorrow, letting the sealant go off. So question is... With a full converter should the oil sit only at the top off the pan when not running? I'm wondering if the aftermarket dip stick is not quite right and to get it to the full mark I'm over filling it. Causing it to leak. With the pan off and dipstick in I could see that to have it at the full mark the oil is over the top off the gasket level and higher then the vacuum cyl. The oil is actually encroaching up the tube to be at the level. Any ideas would be appreciated. Cheers

[Taily]

Might be what you mention.

Have a close look at the selector shaft seal (LHS), the dipstick tube seal and the oil cooler lines as well. The oil level (running or otherwise) as you say is higher than the pan gasket, so if it is even slightly sus it will leak...

I'd be getting in there tomorrow with a can of carby cleaner and rags around the area you feel it is leaking and making it very clean to help with diagnosis.

Failing that have a good look to see if the vac modulator thread isn't leaking or if it isn't dropping out of the oil pump gasket/o-ring seal or the converter seal and running down onto the top edge of the pan area and making its way around the pan gasket? I've just replaced both the oil pump seal, gasket and my converter seal for something similar - much easier while I have the engine out.

You're on the right track!

Dave

[jason.ruff]

When you fill it this time fill it with the recommended quantity of fluid and then check the dipstick. That should give you an answer for the dip stick. Im having similar problem with my T400, leaves lovely puddles of fluid on the shed floor. Very interested in the answer.

[pj350]

Hi RAEME, i hear what your saying , i seem to have the same problem , ive replaced the gasket tightened bolts put sealant on the gasket , the ute sits for sometimes months , sick of having to top up trans fluid. This time ive put in a deep sump pan and and new gasket sealant filter and gone over everything, bolts the way i did it gone over the tension of the bolts for bout the 50 th time now ill just cross my fingers and see . Think its just good luck if they dont leak.

[Big Rob]

This is a common problem, not only on T400's. I've got a Trimatic behind a V8 in one of my Toranas and if I fill it with the correct amount of fluid it shows LOW on the dipstick and the trans slips when cold.

So if I fill it to the FULL mark on the dipstick, it doesn't slip when cold and operates correctly, but leaks when parked for a while.

I have an oil cooler mounted to the radiator instead of using the tank on the bottom of the radiator, so maybe I have a larger cooler than the tank which would explain the trans slipping when cold once the fluid circulates into the cooler.

The leak could be because once I park, the fluid drains from the cooler to the trans and is way above the normal level, possibly then leaking from around the dipstick tube.

So are you running a cooler like me, or the normal tank?

[HK1837]

The original box in my Prem was exactly the same. I took it out to change the rear welch plugs and got it serviced whilst it was out. At the time I couldn't get a genuine O-ring for the dipstick tube and it leaked from there. Found an original and it was all good but still leaked elsewhere.
It ended up being both seals on the speedo drive (inner and outer) and the selector shaft seal. They weep down onto the pan gasket and run around. Both are easy to change when on a hoist.
National transmission parts in Wallsend sell it all and can post.
Wholesale Transmissions in Bayswater would have them too.

http://www.automatictransmission.com.au/
http://www.nationaltransmissionparts.com.au/about-us

For the correct amount of oil follow what the HQ service manual says for the M41 transmission. They take a lot of oil, like 14L or more.

[RAEME]

Hi guys, thanks for taking the time to reply. Sounds like EVERYTHING you guys are talking about is exactly what I'm experiencing. Sad for all of us but makes me feel a bit better knowing it's not an uncommon problem. Before I pulled the sump I removed the inspection plate and checked the front of the trans, all good, I have previously sealed the dip stick tube, all good. I do have an external cooler on it, I left it on the hoist to drain overnight then I cleaned all surfaces with some thinners and sealed with ultra blue on new gasket etc. I'll see what today brings. Cheers

[Frosty]

When you park it for awhile the fluide drains form the torque converter and then leaks as it's too full. Start it once a week might fix it.

[HK1837]

My Prem doesn't leak anymore and rarely gets started.

[Sandvan79]

I've never had a problem with the leaks, I use the cork gasket that comes with the filter, they always seal.
I've seen them leak at the speedo cable, but you can get the two seals to fix that.