I have a stock 2000 f-150 4x4 with 130,000 miles on it with the 4R70W tranny.

I am having the same issue I've read here on this site and several other places around the internet.

Here it is best described by someone else:

The transmission on an intermittent basis has no 3rd gear it goes straight to neutral. It not that 3rd is slipping, its not there at all.

It shifts perfect from 1st to 2nd, then when going into 3rd its just like it has gone straight into neutral. By backing off the throttle and waiting a second it then shifts into Overdrive and it works fine. The transmission downshifts into 3rd perfectly everytime and has never had the problem on the downshift.

Some days it upshifts perfect into 3rd without doing this at all.

His solution was to replace the 2-3 accumulator piston with the updated one. When he went to check his the spring was broken.

So my questions are these:

I need to remove valve body to get to the piston, correct?

Where exactly is it located? Rear passenger side?

Should I swap both out? The 2-3 and 3-4 accumulator? It looks like they have both been updated with rubber pistons.

Should I replace any solenoids, or leave them alone if resistances check out alright?

I don't believe the transmission fluid on this truck has ever been replaced.
Should I flush out entire system including the torque converter, or should I try not to lose as much fluid as possible when doing the work and top off when finished?

Also, it says on the transmission pan that it's equipped with a reusable gasket. Should I reuse it?

I think I found the correct part numbers for this, but could someone concur.

Here they are:

Piston: F7AZ-7F251-AA
Cover and Seal: F4AZ-7F247-A
Upper Spring: F75Z-7F284-AA
Lower Spring: F7AZ-7F284-BA




And of course, anything else you can think of.

Thanks for you help.