Transmission low to intermediate servo

I have a 2001 Winstar with approx 120k miles. At the moment I have got this van, the milage was 58k miles and I' m sure the transmission fluid has never been changed. I have now some very intermitent problem with it as the van has sometimes some hesitations when changing from first to second gear.
I will change the transmission fluid ( only what is in the carter) and filter and also replace the seal(s) of the low to intermediate servo. My question, is there one or two seals to replace, in addition to the gasket of the servo's cover?

There are two o-ring seals. One on the piston (make sure the piston is not cracked or damaged) and one around the base of the cap which is the cylinder that the piston slides back and forth in. The gasket is between matting surfaces of the tranmission case the cap. Two seals and one gasket.

Good luck.

There are two o-ring seals. One on the piston (make sure the piston is not cracked or damaged) and one around the base of the cap which is the cylinder that the piston slides back and forth in. The gasket is between matting surfaces of the tranmission case the cap. Two seals and one gasket.

Good luck.

Hay OldFaithful

This low to intermediate servo piston, Is this an in vehical repair or require removel of the trannie?

I had my trannie stick in first for about 2 blocks...it finally shifted. When I got home I checked the fluid and it was about 1/2 qt low. I added about a qt and I think it shifts smoother....time will tell.

Regards

Dan