Automatic slips in an out of 1st. gear in drive or first. As though it is low on fluid but the fluid levels topped. Working fine the other day. Do you think the fliter could be clogged? The clutches need adjusting? Is there anything I can look for to see if it needs to be overhauled?

 

I have the same truck with the same problem, I asked myself all the same questions, it turned out to be a broken wire down by the tranny, it's a purple wire with a brown stripe. Let me know if this solves the problem, or what exactly the problem was.