I want to kick myself for neglecting the transmission, but hoping there's some life in it. We bought the van used with 45K miles, I changed out all the trans fluid to Amsoil and while discussing with a few distributors how the Amsoil can be good for 140K miles, it was in my best judgement to change every 40-50K regardless. Fact is, I have flushed my trans fluid in my 4l60E every 40K and it has 275K with only a separator plate change that had a check ball punched through it....so I was going to care for this one. Fast forward to 210K miles on the van and the shifts felt only slightly softer at times...but I never got around to changing the fluid. I had the fluid flushed with the BG system at approx 211K and shortly after the shifts seemed to hang or engage twice sometimes. I found out the shop only changed the fluid and not the filter/ fluid. I went to the dealer and purchased a new strainer or filter...however it's referred, and changed the filter. Surprisingly enough, the trans shifted pretty good again so i thought maybe it was slightly starving of fluid or has some debris in a solenoid or other small orifice. About 3K miles later it started shifting weird again so I thought maybe more debris was in the filter. I planned on replacing the filter again but the next day the wife called me on her way to work and said the van isn't moving... Props to her as she said she noticed the rpm's start to rise without accelerating then pulled over and called me. I showed up about 45 min later, engine still running...., I checked the fluid, it was red and didn't smell burnt....hmmm. I put in gear and it engaged firmly. I gave it a short drive to check things out, worked fine, and I made it about 15 of the 20 miles home then at a traffic light it felt like it was in neutral. When I revved it up slightly it didn't move slowly as it was slipping or the clutches were smoked, but with about a 500 RPM rise I could feel the clutches start to engage with a firm shudder ...almost like engaging a manual clutch on a slightly warped flywheel. Felt like it needed a little bit more pump pressure to engage then would move the van once they started to engage but never did fully engage. I did this for about 5 seconds to get it off the road to avoid any possible further damage. It felt totally different than a burnt clutch or band, almost like a partial neutral drop without any hard "bang" engagement of the clutch. I parked it then trailered it home, when I drove it on the trailer it engaged fine and didn't slip at all under mild powerbraking. I'm now going through the process to check the filter after I get those daggone hidden bolts out above the sub frame...... So my question is....I don't know if this is a temp issue with a band or clutches, or a slowly clogging filter...or a solenoid. Any thoughts as what to check alongside the filter please chime in? Thanks!