TH 400

Transmission to Rear-end

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Ron Gusack
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TH 400

Post by Ron Gusack » Thu Apr 09, 2015 5:50 pm

I've run reverse manual 400's since 1981 and never had fluid coming out the relief tube at the top of the case, but I do now. What causes this? A guy on DRR told me to run the trans 1/2 pint low and check to level in third gear.
The things you see when you ain't got your gun!

numboltz
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Re: TH 400

Post by numboltz » Fri Apr 10, 2015 1:16 am

In the olden days 400s had quite a few serious level-related issues. The traditional way to ensure
the level is correct is, with the vehicle sitting level [and cool, unless you're into pain] slowly unbolt the pan so that it comes loose from the case evenly. Let all the oil that wants to, slop out. Then tighten the pan up and check and mark the dipstick at that level, which is full.

400s will bite you if you run them overfull, especially at high revs.

Another reason it can drool like you describe is if the pump comes loose. You did use
new seal washers and/or o-rings didn't you...? I had one that leaked like this right from the factory, seems the factory installer forced the pump in, putting a small but detectable ridge in the oil pump counterbore. Right where the O-ring sits. Didn't puke oil unless it got real hot. Diagnosing that one was fun.

Not.

Ron Gusack
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Re: TH 400

Post by Ron Gusack » Fri Apr 10, 2015 7:02 am

Transmission Specialties did the rebuild and I've never had a problem with their work. This last rebuild I had to replace the case but the pan, dipstick tube and dipstick is the same as it's always been.
The things you see when you ain't got your gun!

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Alan Roehrich
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Re: TH 400

Post by Alan Roehrich » Fri Apr 10, 2015 7:53 pm

Check the vent tube. You should also have a leak proof locking dip stick, at least to race most places.

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