I have a 95 ford explorer and it shifts pretty hard whether in reverse or drive doesn't matter. My husband just fixed the u joints and that took care of the rumbling it was doing. The check engine light does come on and my husband has hooked it up to a scanner but there is no diagnostic results. Any advice or tips would be much appreciated.

Try dropping and cleaning the pan and magnet, changing the filter, and refilling with Mercon V--I recommend Mobil 1 Synthetic ATF. Ford recommends doing this every 30,000 miles. Afterwards, remove the negative battery cable overnight, in order for the PCM to relearn shift points.

If the CEL comes on, a code is stored in the PCM. I behooves you to find out what the code is; otherwise, it may indicate a problem with the PCM itself. I would be sure to clean the main PCM ground. A failing VSS can cause all kinds of shifting problems--it normally causes multiple codes to be thrown.