What does the check valve do in the transmission cooler lines on a 95 3500? This is the rubber hose that connects to the cooler on the passenger side of the motor.Can you replace the rubber hose and leave out the check valve?

 

Pretty sure it is to prevent torque converter drain back to the pan. I have been meaning to change mine, new trans oils in park but haven't had time to yet. DTT makes a replacement line.

 

drill it out a little and the ball and spring will come out.get it out asap cause when it sticks you will fry the planetaries quickly!!!!

 

I was told by The guys at Source Automotive/Dunrite that I needed it, but then I've got a triple lock converter and their best tranny.

 

Some people remove the ball because they feel it causes a restriction and could stick closed overheating the tranny.
I have no idea if this is based on fact or fear.

My rig didn't come with the ball, dealer added it for free when the truck was only a year or so old. It did make a big difference in how soon you could move after being parked for a long time.
When I upgraded to a Suncoast I had them remove it, I don't mind waiting 30 seconds to move.

 

It's based on fear. The valve is an anti-drain back as said- it keeps the TC from draining back to the pan when you park. DON'T DRILL it. Remember, stock 47RE doesn't pump fluid in park- needs to be in a gear or neutral to pump.
Never heard of one actually sticking closed and blocking the line- tho I have had one not seal and still allow drain back.

 

I drilled mine out. I think it causes the trans to leak at the nuetral safety switch and the selector shaft due to fluid overfilling the pan slightly when it drains back.

 

Many years ago Bill from DTT told me that a failure of the check valve will result in a damaged transmission loss of flow i assume . I never got around to it , but i was told to go to neutral after starting the truck to i believe charge convertor. Takes just a few moments then place the transmission in the correct gear . Convertor drainback i think was the reason behind that. I since replaced the transmission with a 6 speed manual so do as you think best