OK here we go again I did my research and pretty well decided that I had hard or broken O-rings on my servo pistons so I printed out the research and a picture of my servo piston and took it to my tranny guy.
he wants somewhere between 150 and $200 to install a new set of servo pistons here’s the kicker he said he had no confidence that that would solve the problem so my question is has anyone on here replaced their servo pistons and did it solve the delayed engagement problem. My tranny works great in all other respects shift great doesin’t leak I don’t want to rebuild it that would cost more than the trucks worth it’s a 97XLT with a 4r44e transmission. I don’t feel comfortable attempting the job myself beyond changing fluid and filters I am just not checked out on automatics.
any input will be read and appreciated thanks in advance, Larry

 

All automatics run on fluid pressure

The main pump(front pump) provides this pressure, it is directly attached to the outside case of the torque converter, so pump is powered by engine RPMs
This means pressure varies by RPMs/pump speed
This pressure is sent to the Valve body where it is routed by passages to the correct clutches and bands(brakes)
There is also an EPC(electronic pressure control) valve to maintain a consistent pressure in the system

The whole valve body with solenoids and new bonded separator plate is not all that expensive, and can be installed without removing transmission

If your transmission guy has a pressure tester, I would pay him to test the pressure to make sure the main pump is not the issue, if it is then trans has to come out, period
If pressure at idle RPMs is OK then yes, repairing valve body can work
But replacing just one part may or may not fix it, thats the gamble, and why your transmission guy said what he said

There are many places in the valve body AND at clutches and bands, where the system can lose pressure, assuming the pump is providing good pressure, 125psi for forward and 175psi for Reverse, this is why Reverse is the first to show a delay or quit working in an automatic, low pressure

 

Thanks for the reply Ron. You seem to know an awful lot about these Rangers. I’m going to test the pressure myself tomorrow I’ve got a gauge I think it’s an 1/8” tap. Funny though my reverse is perfect no delay and pulls strong against stall. I haven’t had a valve body down in 50 years. . Do you think I could change the valve body myself? Ive been a mechanic all my life. I used to own a big truck shop completely overhauled many of those big Detroit diesel’s Do you think the valve body would fix it or do I need to also put in new servo Pistons. My transmission guy says the Bores almost never wear. Tranny guy wants $200 to supply & install servo pistons. Probably looking at $500 or more if he installs the valve body. I’m afraid I might drop one of the band levers and then we looking at a tear down. I am 75 years old and have the old age tremors. That’s why I’m afraid to tackle it. Also do you think I could install the front pump myself if needed? I used to work on the old Ford C3 and Buick Dynaflows, Chevy 2 speeds and Hydromatics back in the 70s You can see from the picture why I said the truck is probably not worth more than $2000. Already put about $300 worth of parts on it. Don’t wanna spend a fortune on a transmission.
Larry

 

What you spend on a vehicle depends on what you want to get out of it
If you are keeping it to drive then estimate the miles it has left as is, i.e. engine and chassis, not brakes and tires

Unless you plan to sell it looks don't matter at this time

If you figure you can get 30k miles or 2 more years out of it and trans repair cost is $500, thats $20/month, 3 years $14/month

Loads of videos on valve body repairs for the 4R44E/4R55E these are the same transmissions, even 5R44E or 5r55E would be similar

 

Don’t know if this reply got posted or not. So here it is again.
Thanks for the reply Ron. You seem to know an awful lot about these Rangers. I’m going to test the pressure myself tomorrow I’ve got a gauge I think it’s an 1/8” tap. Funny though my reverse is perfect no delay and pulls strong against stall. I haven’t had a valve body down in 50 years. . Do you think I could change the valve body myself? Ive been a mechanic all my life. I used to own a big truck shop completely overhauled many of those big Detroit diesel’s Do you think the valve body would fix it or do I need to also put in new servo Pistons. My transmission guy says the Bores almost never wear. Tranny guy wants $200 to supply & install servo pistons. Probably looking at $500 or more if he installs the valve body. I’m afraid I might drop one of the band levers and then we looking at a tear down. I am 75 years old and have the old age tremors. That’s why I’m afraid to tackle it. Also do you think I could install the front pump myself if needed? I used to work on the old Ford C3 and Buick Dynaflows, Chevy 2 speeds and Hydromatics back in the 70s You can see from the picture why I said the truck is probably not worth more than $2000. Already put about $300 worth of parts on it. Don’t wanna spend a fortune on a transmission