2007 F550 4x4 6.0 PSD

This is a work truck but just trying to get an idea of the issues here.

A Couple months ago it started having some slow/harsh engagment from park into either Drive or Reverse. Shop mechanic replaced one of the solenoids and the problem seemed to go away. shortly after that the truck went into the shop for other issues and was down for about 3-4 weeks (cracked heads).

After we got the truck back all was great for about 2 weeks and we put about 2000 miles on the truck, then the problems started.

Trans seems fine when cold as it warms up it starts having issues when you come to a stop and then start to go again it seems as if the trans is in neutral then when it is given a little bit if throttle it slams it into first and takes off, sometimes short shifting some times normally. or other times it seems like it is stuck in 3rd gear from a stop and then with a little throttle it drops back into first.

it only one time ever gave transmission warning light and started flashing the tow/haul light the codes were pulled using an SCT Tuner.

1) P0751 - Shift Solenoid A (SS-A) Performance or Stuck
2) P2700 - Transmission Friction Element (A) Apply Time range/Performance

Shop Mechanic replaced two of the solenoids and the problem was still there, had another mechanic drive it and they say that the transmission is "Sucking Air"

Any ideas?

 

If it's "sucking air" either it is very low on fluid or the internal filter isn't installed correctly.

 

Fluid is full, will have the mech double check the internal filter.