OK lots of people with lots of the same problems with AL4 /dpo gear is , for a start these units need FULLY SYNTHETIC FLUID ,they are subject to overheating if you use dex 2 or 3 ,there is a sensor in the box that will flag up the computer if the fluid gets to hot= bump lockout /limp mode.
Pressure regulation so!inoids are defective ,old ones have a white plastic molding on the top new Borg warner have black but you have to have the software updated if you replace these .
In my modus hand it states that to long in traffic /to long on the motorway /or pulling to much weight will flag computer to limp /lockout, they go on to suggest the thermostat be changed for one with a lower heat value, all of this points to fluid overheating ..
Some of these units don't have a drain plug they only have a level plug , mine does not have the drain plug so I took out the sensor in the bottom of the box and drains out 2 ltrs put the sensor back and then put the container under the level plug started the engine and poured 5 ltrs of FULLY SYNTHETIC FLUID the top of the box and then let it level out with engine running then put plug in,
Took it up the road and punched it up to 65 mph had to slow (traffic) drove from stop like normal and it was as smooth as silk with no hangs between changes ,how long it will last is anyone's guess but a good tip is to put some magnets around the pan on the outside edge !
peterhicks
August 2015