Shifts properly, except into 4th 85 123
 

I have been working on the shifting of my son's 123. I've done a fluid and filter change. I used plain Dexron from NAPA and a new filter. I have adjusted the bowden and none of this seems to affect the shift into 4th. The 1-2 and 2-3 shifts usually take place around 2500 RPM. The shift into 4th won't take place till (usually) 3000-3500 RPM, and then only when I let up on the accelerator. Sometimes, under normal acceleration it works properly, shifts at 2500. Under hard acceleration, it seems to shift properly, shifts into 4th around 4000 RPM. The firmness of the shifts are good, not harsh and no flaring. All of this is being tested on a cold transmission as the car is not yet registered and I only dare to take short trips to test. Hopefully it will get registered today and I can take a long drive and thoroughly test it out.

What do I need to check next?

the button under the accelerator.

You think the kick-down switch may be bad? Come to think of it I have never tried it on this car. I'll check as soon as I get home. Thanks.