Want to drive through Mexico, looking for truck advice

I sold my diesel Mercedes (year 2007 who has DPF but no DEF) to Mexican guy in my neighborhood.
At 190k miles the engine had slight vibration, but the guy took it to Baja and said the engine loved Mexican diesel. Smooth like a silk.
That said from what I have seen, there are not too many diesel shops in Mexico, so buying cheap (aka beaten up) diesel for travel there might become very risky very fast.
IMHO spending money on younger gasser might be wiser.