Here's the scoop: I bought a '76 K5 with the 350/TH350/NP203 combo a few months ago for cheap, mainly because I've always wanted one. The truck needs work, but it was complete driver, with just a little rust in the rockers. Anyway, a few weeks ago the trans started slipping and now I only have 1st and 2nd gear, with Park...no 3rd and no Reverse. Not a big deal, I thought, since I have a junker '81 GMC G20 (3/4 ton) van with the 350/350 combo in it. I'll just "drop and swap" the trannies, right? I've got one sitting there, so why not use it? It's free... Never having done this before, I searched the forums and learned a lot of good stuff, but I couldn't find the exact answer I was looking for - will ANY TH350 swap for ANY other TH350, regardless of the year and application? I know I'll need a transmission jack to get the heavy stuff back into place, but are there any other tips on making this job easier & smoother? Other than bringing it to a shop? On a related note, I like the NP203 just fine, but I've been thinking of adding a MileMarker P/T kit while the tranny and transfer case are already out. Any input? Should I leave it full time or not? I'm not planning on doing any serious wheeling, and it won't be a DD - mainly a weekend use, FS road, hunting/fishing/camping rig with the occasional trip down to the Oregon coast. Will the P/T kit allow for slightly better gas mileage?