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Old 07-08-2010, 07:01 AM
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T-400 questions

I recently swapped a TH400 into my turd. Finally got it going and it started puking fluid out of the bolt holes from the Ultra bell, no worries fixed that. Then it was still puking fluid but I guess now its coming out of the vent on the top.

So heres my few questions, How much does a TH400 hold for fluid, I have a deep pan(2 extra qts) and a TCI 9" converter? I assume its over filled by a lot.

My other question is I guess the trans has a manual/automatic valve body. I asked the guy I bought the trans from about it and he told me "YOU CAN DRIVE THE CAR IN DRIVE IT WILL SHIFT BY ITSELF. BUT THERE IS NO KICK DOWN... I WOULD SHIFT IT YOURSELF." So why wont it kick down? I was shifting the trans manually because I had thought it was a full manual and it felt like dog **** and wouldnt go into 3rd, cruising home in 2nd was fun...

I'm willing to bet being over filled wasnt helping anything. Could I have hurt anything driving it with it being too full? It was only for about 3 miles.

Thanks in advance for the help, this has been a long 3 yr. build.

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Old 07-08-2010, 07:13 AM
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The kick down is electrically triggered by a switch mounted at the accelerator pedal or the carb linkage. The switch connection is on the tranny.

If you're using a deep pan, you should also be using a longer pick up tube for the filter.

The problem w/overfilling the tranny is the fluid will foam up. This will reduce the pressures throughout the tranny. But if you only drove a few miles and didn't hammer it, it'll be fine.

Not having Drive could be the linkage- I would check that first, or right after correcting the fluid level- and I do not know how much it holds. The original dip stick will still read correctly so if it was accurate before the deep pan, it still is.
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Old 07-08-2010, 07:16 AM
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Yeah it has a longer pickup tube.

So a TH400 wont kick down with a cable or anything like a 700r4 would?

Also What does the vacuum mudulator or whatever it is on the pass side do?
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Old 07-08-2010, 07:23 AM
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Quote:
Originally Posted by 84TA406
So a TH400 wont kick down with a cable or anything like a 700r4 would?
Nope.

Quote:
Also What does the vacuum modulator or whatever it is on the pass side do?
Very briefly:

The vacuum modulator along w/the governor, controls shift points when in "D".

The modulator uses vacuum as a "load indicator", the governor uses driveshaft speed as its indicator.
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Old 07-08-2010, 07:24 AM
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Quote:
Originally Posted by 84TA406
So a TH400 wont kick down with a cable or anything like a 700r4 would?

LMAO....you think Cobalt was lying to you or something?
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Old 07-08-2010, 02:34 PM
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No just looking for more clarification. Cobalt has helped me on numerous other occasions. Well looks like I'll be manually shifting it after all. I'm probably better off just ordering a full manual if I have to shift it all the time.
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Old 07-08-2010, 03:31 PM
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The way it is now, will it shift 1st- 2nd- Drive, if you put it in Drive and take off from a stop, or are you missing "D"?

That could be a linkage adjustment problem, at least that's where to start- once the fluid level is corrected.
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Old 07-08-2010, 09:43 PM
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Yeah I can do 1-2-D fine, just doesnt feel like it was going into 3rd at all. Could be the fluid being too full though? Just felt like when I put it in D it wouldnt shift or anything sometimes.
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Old 07-08-2010, 09:52 PM
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The foamy fluid can cause a pressure loss throughout the tranny, so there's a chance the clutches weren't applying hard enough. So, all I can say is get the fluid level correct and road test it again and see what you have.
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