Trans Modulator

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Jan 31, 2013 | 10:20 AM

JimmyS5600

Thread Starter

Melting Slicks

Joined: Mar 2001

Posts: 2,175

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From: Clarence N.Y.

Trans Modulator

Hi Guys, Need to replace the modulator in my 79's trans.
It has been so long since I replaced one I can't recall the
procedure (getting too old) lol
Any help,thanks

Jan 31, 2013 | 11:39 AM

7T1vette

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Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

Go to auto parts store and buy the replacement vacuum modulator for your tranny; jack up car; install new O-ring on stub of new modulator valve; proceed to get dirty.

Put shallow pan under the modultor (to catch any trans fluid that is lost); remove vacuum line from the fitting on the modulator; remove retaining bolt (and clip) from the side of the modulator; have new modulator in you [best] hand ready to install; with other hand, remove the present modulator, then install new modulator in its place quickly to minimize oil loss.

Reinstall retaining bolt and clip and torque to about 10 foot-pounds; reinstall vacuum line; remove self and 'stuff' from under the car; drop jack/car.

Now, go have a beer!

Jan 31, 2013 | 05:50 PM

JimmyS5600

Thread Starter

Melting Slicks

Joined: Mar 2001

Posts: 2,175

Likes: 56

From: Clarence N.Y.

Thanks for your help 7T1, doesn't sound bad at all.

Jan 31, 2013 | 06:55 PM

diehrd

Safety Car

Joined: Jan 2009

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From: New York

I do think there is also a pin up in there , just make sure you do not lose it or not seat it

Jan 31, 2013 | 11:46 PM

7T1vette

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Joined: Jan 2006

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From: Crossville TN

I have never had the modulator valve come out with the vacuum modulator before. But, I suppose that it could. If it does, just replace it into the new modulator in the same orientation as it was removed, then install it with the new modulator, while carefully getting the valve aligned in its bore (valve body).

Feb 1, 2013 | 11:19 AM

JimmyS5600

Thread Starter

Melting Slicks

Joined: Mar 2001

Posts: 2,175

Likes: 56

From: Clarence N.Y.

Thanks diehrd I didn't recall that pin. Will pick up a new modulator tomorrow
and then get busy.

Feb 1, 2013 | 11:26 AM

diehrd

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Joined: Jan 2009

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From: New York

It has been many years that i was in the tranny business ,, but before you get a new one look for a colored stripe on the old one and replace with same

Feb 1, 2013 | 03:58 PM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

You probably can't locate any similar replacement vacuum modulators. You'll likely have to use the "new", smaller design that the chain auto stores sell. It will work OK, even though it has no adjustment capability.