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Old 05-27-2017, 06:45 AM
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T-350 dumping fluid after sitting

I have been looking for a solution to this issue for years, thought I'd see if any of you folks knows.

What causes a TH350 to dump fluid (up to two quarts) onto the floor after sitting for more than a week or two?

I recently swapped a TH350 from one Camaro to another, replaced the front and rear seals, pan gasket and screen, and the kickdown cable o-ring. I still find fluid on the floor after a couple of weeks. Hope someone knows what to do about this, other than just starting and driving the car more often, that's not always possible!

Thank you!

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Old 05-27-2017, 06:59 AM
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Have you check the shift shaft seal? Leaks there are common. Shaft may be worn , rust pitted. New shift shafts are available

When a trans sits for long time. Converter drains back into the trans pans. Raises the fluid level much higher
Dont worry how old you are... it is the mileage on your body that adds up.
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Old 05-27-2017, 09:03 AM
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My Willys T 350 leaked the same. I replaced every seal I could without pulling it

out. Still leaked.

Finally I installed a deep pan with filter extension. I got a new dipstick cable from LoKar.

Then I filled the trans to the bottom of the pan rail. I ran the car until warmed up...about half hour. Then drained two quarts out. The extra pan capacity. I measured the depth and trimmed the new cable as needed. I have no more leaks. I was going to put a baffle in the pan to prevent the oil from sloshing away from the pickup but I didn't. I don't drive hard enough to cause this.

My solution.

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Old 05-27-2017, 06:28 PM
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If the leak is at the front seal, you might check the pump bushing for wear.
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Old 05-27-2017, 08:18 PM
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Thank you, some good ideas

It is possible that the fluid level could be part of the issue, if I added a spacer to lower the filter screen into the fluid, that could make a difference. The shift shaft is not pitted, the leak is very likely caused by the converter draining into the pan, that is something I suspected all these years. I'll replace the modulator seal and the speedometer gear seal, maybe the two of those will help! Thank you for responding.
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Old 05-27-2017, 08:43 PM
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My bucket would do the leak thing periodically. I narrowed it down to... If it was run up to operating temp, or approx 20 miles or more, the trans was fine. No leaks. But, if it was run on a short, less than 10 mile jaunt. Like a lunch run. it would leak a small lake by time work day was done. Around dip stick and shaft seal..Even new ones.. Finally replaced the trans.. Cured!
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Old 05-30-2017, 04:30 AM
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Did you replace the dip stick o-ring?
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Old 05-30-2017, 08:26 AM
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Pay attention to the "O" ring groove on the tube.
I have seen them crack.
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Old 06-04-2017, 06:08 AM
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I would go under there with a can of brake clean and a rag and clean/dry around all the components that can leak and watch it very closely to see where it is actually coming from. There should be definite evidence where the leak is and you can focus on that instead of guessing and replacing items that aren't the cause.

I know this is frustrating, I have a couple that leak after sitting too, even a newly rebuilt 2004r. Turns out the input yoke has slight scoring and the fluid is able to migrate out thru those slight marks after sitting long enough. I have synthetic fluid and that stuff is much harder to contain than traditional fluid.

I'll second looking for a crack in the o-ring depression in the dipstick tube. After having tried many times to get one to stop leaking, I finally found the hairline crack and replaced it.
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