700R4 2nd apply pin question

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Feb 19, 2008 | 08:08 AM

Tom454

Thread Starter

Le Mans Master

Joined: Apr 1999

Posts: 6,134

Likes: 46

From: Raleigh North Carolina

700R4 2nd apply pin question

I am overhauling two 700R4's (a 1986 6MDM and a 1991 1WCM) and ran across a confusement (new word). The 2nd apply pin in the 1WCM has two grooves cut for seals. It was mushroomed near the retaining clip, so I had to carefully file it to get the servo apart. Since I was at the counter at Transtar, I picked up a new pin... GM ACDelco #8680500. The ACDelco replacement pin is the correct length (medium/2.67-2.68), but does not have the two grooves cut for the seals. My 1986 GM Shop Manual shows the grooves in the pin. I do not have a 1991 manual for comparison. The 1991 is a rebuilt by "ACCURATE" Transmissions... originally purchased from Advance Auto.

I can re-use the old pin if necessary.

How concerned should I be that the new ACDelco replacement pin does not have the grooves/seals?

Feb 19, 2008 | 05:25 PM

Pete K

Race Director

Joined: Feb 2004

Posts: 12,518

Likes: 19

Quote:

Originally Posted by Tom454

I normally use the old style pin whenever possible because it seals better with the 2 teflon seals. As you mentioned, new pins and those made after 1986 do not have them. 2 less seals to pinch during assembly. As long as the pin is the correct length for correct servo pin apply, use the best one you have. I normally aim for .090 servo cover movement.

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