Topic: 1966 289 C4 not shifting 2nd to 3rd

[socalgt]

Fluid is correct level and recently changed including filter, modulator valve replaced, verified vacuum line in tact and connected both ends, but transmission does not shift from 2nd to 3rd gear.  Fine from 1st to 2nd.  Verified gear selector correctly positioned.  This problem started recently and has been this way a week or so.  Hoping there might be another "simple" thing I can try, short of having it rebuilt.

Thank You..... 

[socalgt]

I"m putting a new valve body(same exact type) and hope that cures things.  I'll post the results in case it might help someone in the future with the same or similar problem.

[67gtasanjose]

When you changed the modulator valve, did you locate and confirm the "pin" went back in? The "pin" gets lost sometimes.

[RoyceP]

I would do a line pressure check first. Likely you have an internal seal that is blown that is causing you to lose servo pressure. No sense wasting money on a valve body if the pressure is low. Takes 5 minutes do accomplish, equipment needed is a hose and a gage.

When you changed the modulator valve, did you locate and confirm the "pin" went back in? The "pin" gets lost sometimes.

[socalgt]

This is embarrassing.....but.....I've been driving a variety of other cars recently.  When I went back to driving my Mustang, I did not feel it was shifting into third....kept waiting and didn't feel it and seemed like the rpm's(and noise)were high.  I drove it again today, starting with the gear selector in the "dot" position so it would start out in 2nd gear so any shift felt would be up to 3rd.  I realized it was shifting into 3rd very early, as slow as 30 mph, and smoothly that I didn't feel it.  I've driven and owned many of these, so I really can't explain it, but I was not feeling the shift into 3rd even though it was.   Sorry for the posting of a problem did didn't actually exist....and thanks for the replies.

Bottom line...…."operator error."  I did talk to a friend with the same car and transmission and he admitted he sometimes wasn't sure his C4 was upshifting into 3rd, so I don't feel so foolish.

[jwc66k]

Smooth, ain't it. You should try a "K" Mustang with a C4. How you start, from a full stop in an "A" code engine and a C4 automatic, causes "chirps" when going from 1st to 2nd in a "K" Mustang. It brings out the kid in me.
Jim

[RoyceP]

This is the kind of error I wish I had sometimes. Sadly for me it's always been a transmission needed to be rebuilt. Congratulations on the great news!

This is embarrassing.....but.....I've been driving a variety of other cars recently.  When I went back to driving my Mustang, I did not feel it was shifting into third....kept waiting and didn't feel it and seemed like the rpm's(and noise)were high.  I drove it again today, starting with the gear selector in the "dot" position so it would start out in 2nd gear so any shift felt would be up to 3rd.  I realized it was shifting into 3rd very early, as slow as 30 mph, and smoothly that I didn't feel it.  I've driven and owned many of these, so I really can't explain it, but I was not feeling the shift into 3rd even though it was.   Sorry for the posting of a problem did didn't actually exist....and thanks for the replies.

Bottom line...…."operator error."  I did talk to a friend with the same car and transmission and he admitted he sometimes wasn't sure his C4 was upshifting into 3rd, so I don't feel so foolish.