Originally Posted by Brian Carlton

Steve, the hard shifts and the delayed shifts are two different issues.

With regard to the hard shifts, setup a vacuum gauge so that you can read the transmission vacuum while you drive it. If you do not have sufficient transmission vacuum at low and moderate power settings, you will get hard shifts. This could be due to blockage, or leakage in the EGR system, or a bad trans modulator valve. I don't have the data off the top of my head on the values for the vacuum at different points along the load curve, but, I think that there is data in the archives. The main thing to look at is whether you have a high vacuum at light throttle positions as it shifts. The vacuum should drop at greater pedal positions and then drop to nearly zero at full pedal.

The delayed shifts may require an adjustment in the Bowden cable, which I believe that the '84 still has. You want to get a little more slack in the cable so that is shifts earlier.