I'm looking at a used 300SD that has a trans slip from 1-2nd. I've done a pretty extensive search through posts on trans slipping and seen quite a bit on the 2-3 slip, how to adjust/replace the valve, check for excess fluid, run TransX through, etc. My question is although the 2-3 seems relatively common and is usually correctable or compensatable through the valve adjustments or the other steps mentioned above, do the same principals apply for a 1st-2nd slip or does that usually indicate a more serious issue?

Thanks,
Ray Ackley