'91 transmission problems?

My '91 Explorer has been perfect until now. Has 117,000 miles. Exc. cond. Kept in garage at all times. Love it with all my heart. Second owner. First owner treated it like a baby, so well-cared for. Since weather turned cold, can use reverse o.k. to back out of gargage, use drive to get out driveway o.k., drive to end of road about 1/4 mile and wait for traffic to clear before proceeding onto main highway. When o.k. to proceed, transmission seems to be in neutral and cannot continue without wiggling gearshift back and forth. It only does this the first time out and never did it during the summer. Did not do it last winter. Have not seen any indication of transmission fluid leak. Anyone else had this problem or any of you auto guys have any ideas?? Thanks

Could be some valves sticking in the valve body. Explorers are known for horrible transmission woes. Make sure the fluid level is up. If the modulator goes in the transmission, it will burn transmission fluid and not leak it. This sounds like exactly what happened to my 94 about a year or so ago in the winter. Probably can't hurt it to change the transmission fluid and filter either. Good Luck