I'm just curious as to the highest miles these transmissions see.

I just came across a '94 4L60E with over 314K original miles in a farm truck turned almost daily driver. Owner said it was used to pull just about anything.

Started slipping going into 2nd.

What I think happened was that the 1-2 accumulator wore out and burned the 2-4 band and tore up the reverse input drum. Aside from that it was still driving with piston seals that cracked when removed.

 

Just so everyone is aware. If you purchase a "used" reverse input drum, they just turn it down so it's smooth again. I got one and it's just been smoothed. I have to send the old one back as a core. Had I known, I would have taken it to work and had a machinist do it.

It's back together and we'll see how it turns out. Overall I think I've found a new appreciation for these transmissions. I think I could start a preventative maintenance build sheet after doing this one.

Replace all accumulator pistons every 150K miles and it should last forever if fluids are changed regularly.