Thank you all in advance for replying to my threads. I have a lot of questions. I have a 1999 K1500 Suburban LS, 5.7L with 213K miles. It runs very well, I drive it on trips for work often and I don't have problems aside from a minor thing here and there. It doesn't leak any fluids, the "Service Engine Soon" light is on but the code indicates an O2 sensor, which I'm replacing soon. I use it off road with some regularity, but not heavy 4x4 stuff, just fishing, camping etc. My question is about the value of overhauling/rebuilding the transmission and/or the engine. I'm in industrial maintenance and reliability professionally, so I understand equipment wear, etc. The old adage "if it's ain't broke, don't fix it" comes to mind. But I assume that with as many miles as it has that things will start wearing out. I've done a tune up (plugs, wires, rotor button, cap) replaced the fuel filter, radiator (it was leaking) water pump (leaking from the weep hole). I've got some slop in the steering that my tire guy diagnosed as a worn idler arm, which I'm replacing soon, as well as shocks. Also on my repair list are u-joints, I'm considering CV joints (even though I have no indications of failure yet) but these are relatively low cost. Is it worth it, if I'm planning on holding on to this truck, to go ahead and budget a trans rebuild and even an engine rebuild? Or do I wait until they clearly need them? Thanks again for any input!