Having just run across these posts the other day, I gotta say "nice"! Big Blue24 turning that forward drum pp over was pretty creative! Even tho I have never needed to do so, it's good to have another option. One of my best friends was one of the 1st to prove to the big boys with the big dollars that a country boy with common sense and used parts could consistently pull a sled further with an automatic than his clutch would. We have had incredible luck with 4 forward clutches and 4-5 direct clutches with proper pressure, valve body, and torq convertor behind 1,000+ hp Dodge Cummins. But, if the game stopped there, then I'd still be driving my 160 hp Cummins rotary pump for fun! I have several extreme trannys ready to try and building others, so maybe I can Share a few lessons learned the hard way and some from others that shared. Like most, I build od first & you all covered that pretty well, but I haven't seen much, if any, attention to oiling that section. Stock OD piston retainers don't have the hole in the same place. Intermediate shafts have different thickness spacers at tail end. The snap ring holding OD unit in case can be worn or distorted. Sometimes it needs to be turned over or replaced. All these things can and often do (even from the factory) cause a restriction in flow to OD. I always use the Sonnax OD piston retainer in my builds because it has the hole right as well as better lube to shaft. I enlarge hole thru case & make sure hole in shaft lines up proper. You don't want to look in there & see part of the race. If you don't think this is important, then build your next engine with the oil passages blocked or restricted & see how long it lasts. Restriction here might make your pressure gauge look good because you don't have flow, but you need flow!!
You already covered planetary play and there are different opinions on overall end play. I see it being critical when adding that fifth clutch to the forward drum. It's easy to add that extra clutch, but having it start out on, much less stay on the splines may not be. I like to assemble tranny stock first and set end play with thrust washers and different thickness thrust between shafts. They come in three sizes. All trannys & components are not the same, even before wear. If you build front section upright in torq convertor, you can again try to select the right thrust to line up oil passages and see where sealing rings will sit and how far they could move with your end play. Too much endplay and again no flow where you want it I shoot for a max of.025 total endplay, seeing only a need for a thin layer of fluid between thrust washers. Now build direct how you want. Build it for your app. A 5 disc drum with Suncoast billet piston and .170 Alto PP will usually take 8 .059 Stage1 red Raybestos clutches & 8 .069 kolene steels. Same setup will also take 6 .086 steels and 6 .084 hi energy Raybestos. It seems that thicker takes the heat from constant shifting due to already discussed bind up. Suncoast billet piston takes 10 return springs and TCS makes a nice one for up to 15 springs like the stock piston can take. Number of springs, line pressure, lever ratio, servos and more are involved in bind up. With the power some of us have, you may not know how bad it kicked your ass until you gotta rebuild! There is good read at DTT website's forum. Bill Kondolay tells it like it is! While there check out there Assassin fuel pump. Also Randy on Ebay sells real nice servos. I've used them & like them!!
OK Drop in forward drum and input shaft. Remove all but one clutch. Take everything off intermediate shaft and put planetary and snap ring back on. Place thrust & spacer in end of input shaft, then add intermediate and planetary. Only now can you see where first clutch will ride. Add all five clutches and steels. Is fifth clutch on splines and will it still be on splines when compressed with allowed endplay?? If not you gotta change thrusts and still maintain endplay. It is time consuming It's frustrating sometimes, but there is no room for error. You could have fifth clutch spinning free above splines or where it will come off splines when compressed. Not good!!!! Usually the bottom pressure plate needs machined down.
While we on forward drum and added a clutch and we got fluid flowing good at higher pressure, probably really tired from reassembling tranny numerous times while doing overtime to pay for it, do I really need that $69 billet forward piston from Suncoast? I'd suggest you get the .840 one and prob not the .780. And yes the .840 can work with either spring. Always use a new spring and make sure there is no play when waved snap ring is on. Rarely will there be any, but if there is, you can use weaker old style to get it out. I think new style stronger & better in most cases. Depending on line pressure you decide to shoot for you may need to get the metal cush ring from T'Flite Patty on Ebay so the plastic one dont squeeze out like jello, If you too had to overkill it with 8 clutches in direct & know you need a minimum of.010 clearance per clutch and preferred .015 per clutch for street, then you need good pressure to close that gap quick while overcoming those extra springs that you need to open it back up.
If any made it this far and have all assemled, Big Blue24 told you right well about band, strut, etc, but if you got cheap and bought the strut with the ribs on the side and not like his, make absolutely positive that the ribs are turned up away from valve body!! Turned wrong it will rub vb & not let band release. Band & drum will burn up quick, taking clutches & more!! To be safe, I turn the billet ones that way also.
Back up to OD for a second & if you need help setting clearance on piston, go here:
http://www.atsdiesel.com/PDF/47RE_Overhaul_Instructions_A1.pdf
If all that seemed like a lot, then order a valve body!! If you did all this to drag race, Griner is working on a 618/overdrive transbrake so make sure you went full billet!
