Not as easy as it looks is it?

I've not done any on a 6.7. but have done too many to even count on other trucks and cars. You would not believe what's involved sometimes.

Gain access anyway you can. If it means pulling something off, then do it. I don't like the splicing or soft line idea. Both would work, but putting the correct parts is always best.

Yes they're under pressure, but not as much as you would think. It's usually between 10 to 20 psi at the cooler.

 

Yes they're under pressure, but not as much as you would think. It's usually between 10 to 20 psi at the cooler.

Older transmissions had 10-20 PSI in the cooler lines. The 5R110W had about 60 PSI. I would expect the 6R140 is at least 60 PSI, but I have no hard data on that.

 

It's gotten to where when I do them on a chevy truck, especially a Duramax, I pull the front facia, front bumper and front axle. It can be done without pulling all of that, but you fight with it for half a day.

Also twisting helps. When inserting the lines, try spinning them as you go.

 

If you're flushing a newer transmission that has an internal thermostat you will see very low pressure in the cooler line. That's because the thermostat will be closed and only 10% of the normal flow is going to the coolers. So you can expect to see about 10% of the normal pressure. This is why I have repeatedly said you can't flush one of these transmissions without a heated flush machine.

 

Sure you can, just takes longer is all.