Hi all- a newbi question. I have a 1991 F150, 351 5.8L 4x4 Auto trans.

The transmission was slipping between gear changes when it gets hot (driven 20-30 minutes in city traffic) so I took it to a Ford house and they replaced a block with 4 vavles from the transmission- First off what is this?

The mechanic told me it shifted the gears as the pressure builds up, opening one valve at a time, with each having four different tensioned spring changing between the gears.

I though this fixed it, but now its staring to return. any ideas what it could be. Thanks

 

Sounds like he replaced the valve body, or the accumulators in the valve body. Without more info it's hard to say what the problem is, there are many things that can cause a trans to slip when it is hot.

-Jon