Does anyone know a cure for jumping out of 4th gear into a false nuetral?  It does it under a load like going up a hill or passing.  

Hi; When was the last time the oil was changed?Sometimes dirty oil will make the rears not engauge fully. Other wise the shift dogs may need to be replaced. Maybe the third - forth slider may just be worn out. In any case the fix is not cheep or simple. Try the easy stuff first. change the oil and see what happens...scruffy..  

Ther is an excellent article on Moccsplace.com under the "garage" section called "False Neutral Fix", guy seems pretty knowledgable, looks easy enough to do if you have the time, good luck!