The trans in my 110,000 mile '95 525IT will not shift into 3rd or 4th. 1st ,2nd and reverse work fine.When in D it will shift 1-2 but then just feels like neutral in 3rd.This happen after the car sat overnight prior to that no indication of a problem.Not sure of the trans model number but it is a GM Hydramatic as I noticed a placard on the side of the trans when I replaced a shift shaft seal awhile ago.Anybody have any suggestions? Thanks.