Chattering? C6

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May 14, 2005 | 06:19 PM

rusty70f100

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From: Iowa

Chattering? C6

Ok boys, I've got one for ya.

Last winter, I put a 400hp Ford FE 390, with a boatload of torque to match, into my 1970 F100. It replaced the old 360 that was in it. A long time ago, my brother put a TCI valve body in this C6. It has run good for many years, and last year I had to adjust the intermediate band because of wear. I put a new filter in it at the same time, and cleaned out the pan. I have been using Type F fluid, which is what that year C6 calls for. So far it has worked good, up 'till now.

So I notice today that it kind of stumbles a little after takeoff. It's not in the engine, it's like 20ft after a dead stop, it'll kind of stumble / chatter for a second or two, then it'll be fine until I come to another dead stop, then repeat the process. I've already checked u-joints, they're fine.

Now, I am by no means the transmission expert. So far my thinking is to do what I did before, and that is replace the fluid and filter, and adjust the intermediate band. I'm just confused, because like I said, I'm not the transmission guy. I can build FE engines in my sleep, but automatic transmissions are a mystery.

Thoughts?

May 14, 2005 | 07:36 PM

rusty70f100

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Update

I just took it for another test run. If I manually shift the gears it works just fine. It only happens when I leave it in drive. It also appears to happen during the 2-3 shift.

May 14, 2005 | 11:34 PM

"Beemer Nut"

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From: "Islander"

Rusty, if your intermediate band adjustment is too tight you'll have bind up were 2nd isn't released before 3rd engagement. Alot of heat, wear on the band and clutches if not corrected. Remember the jam nut is a one shot item unless you like leaks.

Carl....=o&o>....

May 15, 2005 | 12:12 PM

rusty70f100

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That's the thing. I adjusted the intermediate band last year, and it's worked good for a long time. They dont get tighter as they wear out, do they?

May 15, 2005 | 12:57 PM

"Beemer Nut"

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From: "Islander"

Rusty they get loose as the friction material wears away. A soft smooth shifting trans will wear away long before a "firm" shifting trans. Less heat is generated which extends fluid life. The adjusting jam nut is one shot, find the correct adjustment with the old nut then replace with new to prevent a slow leak. Different types of bands, peoples "secret ideas" about torque on the bolt and amount to back off vary that's why I'm being cautious not giving specs. With the age / design and fluid control of C-6 vs GM's 400's you will never have a safe high torque / hp shifting trans that shifts the same at light throttle. I have a forged band with extra cuts in the friction material to allow fluid to excape between band and drum, firmer shift. Too firm at light throttle but firm at full throttle 4,500 rpm's, extra plates, full roller / needle bearing, pressurized sprag. Trans has to be built to the motors hp / tq rpm's and intended use. Remote cooler and filter w / magnet is a plus. New or reman custom convertors can fail at low mileage. Done rambling.

Carl....=o&o>....

May 15, 2005 | 01:05 PM

"Beemer Nut"

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From: "Islander"

Rusty, I forgot to add that C-4's / C-6's are alot more sensitive to small partical jam up vs 350 / 400 GM transmissions, they can pass rocks and still function. GM has a better valve control system hydraulicly over all as well as it's made of iron vs Ford's aluminum.
Carl....=o&o>....

May 15, 2005 | 04:01 PM

rusty70f100

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From: Iowa

Well, I'm not putting a GM transmission behind it, if that's what you're getting at.

The problem has corrected itself. I manually shifted it for a few trips, and then tried it. Problem eliminated. My guess would be a piece of crud in the valve body. Time to change fluid and filter, I guess.