I have a 99 f150 with a 5.4 and auto trans with 115000 mile the overdrive last week started acting up. When it would shift into the passing gear the truck would rev up to about 4000 rpms then slam into gear. So I have drove the truck with the overdrive turned off and it acts fine. Today I went to leave work and put it into gear and waited to jump into traffic and when i went to go it slipped for just a second then slammed into gear. I checked my trans fluid level tonight and it was a court low so I added some and took it for a ride hoping the problem was fixed but I made it almost 3/4 of the way around the block while the trans slipped then it finally locked into gear and drove fine the rest of my drive. It shifted up and down without any prob but when i baked up and put it back into drive it took 30 sec before i felt the trans go into gear. All the forums I have saw said to flush tranny and change the filter but I just dont know to me it seems like its something more than fluid and filter. But I'm no pro I was wondering if anyone had any ideas cause i can get a different trans for $350 if its a problem.

 

Spend the $350.

 

I would also like to add my issue to this one. I am having a similar issue. After having these symptoms and having the tranny completely rebuilt, the symptoms continued. Ultimately the valve body was replaced (bad selenoids?), the issue was resolved temporarily and its started again, 1.5 yrs later. These symptoms are not easily diagnosed because they do not happen consistently.
Under warranty, but tranny shop says they cannot identify the symptoms and claim to have pressure tested the hydraulics and all checks out fine.
I am determined to get this repaired by them under warranty, but I am at a loss due to the inconsistent sysmptoms and diagnosis difficulties.
Looking for any help I can get!!!

 

AZ97, I see you are new to the forum - welcome!

However, you are going about trying to get help in the wrong way. It's bad forum etiquette to jump into multiple threads started by other people to try to get help. The proper way to do it is start your own thread.