Author Topic: TH400 Question  (Read 1762 times)

Offline 1973c20

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TH400 Question
« on: September 13, 2007, 06:11:04 PM »
What are the most common places on the TH400 for a trans fluid leak to occur? I'm going to be replacing the dipstick and pulling off the pan to put in a shift kit so those will be sealed, but where else is there to look out for?

Offline DnStClr

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Re: TH400 Question
« Reply #1 on: September 14, 2007, 01:47:17 AM »
The most common is probably the pan gasket, which can be resealed by tightening the pan bolts, but DON'T overtighten. That causes leaks too.
 The front seal is always a good place for a leak too. You can remove the flywheel cover for a good look at the torque converter, and if there's oil all over the converter then you have a front seal leaking.
Don
87 Chevy Silverado

Offline 1973c20

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Re: TH400 Question
« Reply #2 on: September 14, 2007, 08:42:35 AM »
another question, is it safe to run without the flywheel access cover or should i think about investing in one?

Offline FlatBlack77

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Re: TH400 Question
« Reply #3 on: September 14, 2007, 09:10:58 AM »
Someone who had my truck before me didn't put the cover back on for some reason. I have a couple around that i could put on but i haven't gotten around to it yet. my tranny was just rebuilt with a shift kit before i got the truck so it coul dhave been whoever did that. it hangs kinda close to the ground but my oil pan is gunna hit before it does and ive had my truck off road a bunch of times and nbever had it touch.
"When you are a hammer, everything looks like a nail"
'77 C/10 - 350/350 mild street motor

Offline ccz145a

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Re: TH400 Question
« Reply #4 on: September 14, 2007, 09:12:32 AM »
Mine has been off for 17yrs with no leaks from the front seal... but I only put about 1500mi/yr on it anymore. Of course it would be best to put one on.
1975 C10 Silverado LWB, 454CID, TH400, 10bolt 3.42
11MPG Downhill w/tailwind (but there ain't no hills here)

Offline chevyguy5894

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Re: TH400 Question
« Reply #5 on: September 22, 2007, 01:40:56 PM »
Do you have a o-ring style dipstick? My 76 has one havent been able to find a dipstick to fit mine that has the big rubber groumet.

Offline 1973c20

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Re: TH400 Question
« Reply #6 on: September 22, 2007, 07:59:26 PM »
I'd assume that they're all the same style for the TH400....have you tried  ?