I have a 93 gmc suburban.
bought it about 10 years ago and a few years after getting it the transmission went out.

I bought a 4l60e from a 93 astrovan, put new filter and seals on it and that transmission lasted a good 5 years.

A few years ago the transmission started to leak from the tail end. I read that it was just an o-ring in the tail area that was not under pressure but never got around to replacing the o-ring so just dealt with it leaking and had to add about a quart of fluid every week or so.

I let my nephew borrow the truck for a few weeks and told him to keep the trans fluid topped off cause it leaked.

well he gave it back to me way overfilled with trans fluid. It would then shift hard into every gear and the fluid smelled burnt.

The suburban has sat for the past couple years and would like to get it running again.

I know there was different versions of the 4l60e. What years 4l60e can I use?
Should i try changing fluid/filter first?