My first post, and this was for a 4x4 not a Z28 so remove if inappropriate, but I was drawn to this forum because of the high quality posts on trannies. My first rebuild was a failure and I hoping a 2nd set of eyes will notice whatever it is that I overlooked. 1976 4x4 got an engine swap and transfer case swap and, even though the 20 year old storebought rebuilt TH350 was still running, I figured I might as well freshen it up while it was out. Never rebuilt an auto before but it's something I wanted to learn, plus I wanted to do some upgrades. I followed the Sessions and the Haynes books and online how-to's, including Jakes, as best I could. -- red alto clutches -- new seals -- new bushings -- new modulator -- new intermediate roller clutch -- hardened intermediate outer race -- 4 small case-saver inserts plus one large case-saver insert -- direct clutch piston machined to 0.695" thick to allow 5th set of plates. I just noticed that Sessions recommends 0.730" thick while Jake suggested 0.675". Don't remember why I chose 0.695" but probably to dial in clearance. -- dual feed direct clutch by omitting center seal from direct clutch drum, omitting middle pump stator sealing ring, and plugging the port in the front of the case. -- drilled spacer plate 0.125" at 2nd & 3rd feed holes as suggested in Jake's thread. -- during the rebuild, I had some uncertainties about the valve body gaskets included in the kit. They were unmarked, no instructions were included, and different than what had been in case when I opened it up (some kind of shift kit), but I verified that all the holes in the spacer plate lined up with holes in the gaskets. One gasket between case and plate, second gasket (with "Z" cutout) between plate and valve body. -- upon re-assembly I noted manual valve adjustment was slightly out of spec in "D" position, as per p.207 of Sessions book. I did not take a photo or write anything down, but seem to remember that the valve stuck out a little too much. I was reluctant to bend the S link to make the correction so I left it that way. UPDATE: Ron's book had a typo and my manual valve adjustment was actually fine, see post #2. -- old "RV" torque converter replaced with new, unmarked but presumably OEM-spec torque converter that came with the rebuilt tranny 20 years ago and had never been used. -- re-adjusted kickdown cable (had to fabricate a new kickdown cable bracket due to a manifold swap). After starting the new engine and bringing the tranny fluid up to level, it was immediately obvious that something was not right with the rebuilt tranny. -- no clunk when shifting into reverse. -- roughly 2000 rpm required to initiate movement when warm, more so when cold. -- 1-2 shift worked OK, but there was no 2-3 shift. -- several second delay when manually downshifting from 2 to 1. -- sometimes shifting to P would engage the parking pawl, but other times tranny would remain in reverse (I never adjusted the external shift linkage). Drove 5 miles that way, came home, looked things over, found modulator vacuum line had been knocked loose at manifold, hooked it back up and took another 5 mile test drive but still no 2-3 shift and generally no improvement. So pulled tranny and did autopsy. -- pan & filter clean but oil looked and smelled burnt. -- crud above direct clutch as shown in photo. Clutch material? -- low-reverse clutches toast after only 10 miles, as shown in photo. -- forward clutches toast after only 10 miles, as shown in photo. -- forward clutch assembly clearance was 0.146" with the burnt clutches. I don't recall the as-installed clearance but pretty sure it was not that sloppy. -- no other damage or assembly errors detected. Seals all intact. No missing or out-of-order pieces. -- governor seems good. -- the new modulator that came with the kit did not seem right. It holds vacuum but barely moves when vacuum is applied. Here's a comparison of depth of plunger inside modulator for 3 different modulators, "as-is": Kit New, no vac = 0.316" depth, 15 inch vac = 0.333" Old, no vac = 0.262" depth, 15 inch vac = 0.415" Slightly Used, no vac = 0.347" depth, 15 inch = 0.400" depth So the kit modulator may have been inoperative, but still, that would not explain the dramatic failures, would it? Gentlemen, what am I missing? I don't want to put the tranny back together until I've identified a smoking gun.