There's two members here who could call their trucks "Slave Eaters"......myself being one of them. It's most likely the slave again. Poor Design and can go just about any minute....ticking time bomb.
At 133k, it may be best to replace that stock clutch anyway. And whenever a new p-plate is installed, it's suggested to replace the slave as well. If an old slave is left in there but a new p-plate is in there, the slave may fail because of all the new found force it's gonna put onto the new tight p-plate.
'01 XLT disguised as a '03 Fx4 Level II.