99 Rangler XLT, Auto tranny
Drove about an hour in 70 degree weather truck shifted fine entire time.
Shut it off to get gas and leaving the lot it slipped from 1st to second. I Stopped and manually shifted from 1st to 2nd and 3rd and it worked fine, thereafter. This has happened numerous times now and works fine when manually shifting up to drive and then leaving it in drive. Only seems to occur when going from park to drive and trying to take off.

Its just from park to drive when hot that this occurs. Not a problem all winter when air temp was cold
One repair shop suggested replacing the solenoids in the transmission saying it sounds like they are heating up and breaking down, one repair shop suggest flush and fill or rebuild and not to bother replacing solenoids, neither has looked at it yet.

Any advice?

 

you could have a blown separator plate, just replaced redneckstones on saturday.

if you feel mechanically inclined enough, remove the valve body and update it with the update kit ford sells and replace the separator plate with the updated one