This is some stuff I put into my tranny. The front drum is aluminum with a steel sleeve on it. The light weight weight parts saved 6 1/2 pounds off the rotating assambly. Kim
You should focus on stuff not exploding for your own safety, so billet front drum and low band apply vb would be mandatory I guess. The rest is really not must have if you are willing to look into the transmission more often.Im looking to make between 800-900 with my procharged G3 hemi, and my 727 does not have close to the parts list mentioned in this thread....Fingers crossed it lives for a bit before I have to upgrade lol
So how is longevity of aluminium drums? Do they get wear marks from steels inside? Whats your experience?This is some stuff I put into my tranny. The front drum is aluminum with a steel sleeve on it. The light weight weight parts saved 6 1/2 pounds off the rotating assambly. Kim
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So aftermarket front drum can still explode? I was reading somewhere that factory drum explodes arouns 13000rpm and A&A billet steel gets deformed at over 30000 but does not explode...Mine also has JW SFI Spec belhousing and using a TCI SFI spec scatter shield (just in case).
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Experience exchange is the best you can get. There are many fairy tales in what we do.You still need the shield or blanket because it’s in the rule book that if you don’t have an SFI case you need to run one. Anything can fail, but it’s pretty unlikely the billet front drum will fail. Not that my opinion matters much.
Kim’s aluminum drum with steel liner is so that you can run Teflon sealing rings opposed to stainless steel rings with the aluminum drum. It’s a smart move. Yes the front aluminum drum will have small wear spots where the steels are splined into the drum but it’s not that much of a concern. The band is where wear comes from over time. The rear drum isn’t as much of a concern to run aluminum because there’s no band riding on the drum. It’s recommended by A&A to perform transmission service every 25-35 passes with an aluminum drum. I have multiple transmissions out there right now with aluminum front, rear, and low/reverse drums in them that have been in them for over 10 years with a lot of runs on them. low 9 second heavy cars. They are still going strong. My aluminum drum I ditched last year for steel but the drum was over 15 years old and I sold it because it was in good shape. Thats just my opinion and experience. I by no means know everything there is and I consider myself a humble person, but these 727s aren’t secretive and the upgrades are not difficult.
RJ
No LBA here. 2nd gear burnouts always. A billet front drum will come one day. Always run a blanket on my stuff. Should work for a bit until i can get back in to upgrade it.You should focus on stuff not exploding for your own safety, so billet front drum and low band apply vb would be mandatory I guess. The rest is really not must have if you are willing to look into the transmission more often.
I am doing all the stuff because my son is very often in the passengers seat. Want to minimize risk mostly because of himNo LBA here. 2nd gear burnouts always. A billet front drum will come one day. Always run a blanket on my stuff. Should work for a bit until i can get back in to upgrade it.
No LBA here. 2nd gear burnouts always. A billet front drum will come one day. Always run a blanket on my stuff. Should work for a bit until i can get back in to upgrade it.
I only knew of a couple racers with alum drums. They said no problems with over 400 runs in 10 second cars. Mine had over 200 runs when I pulled the pan to have a look see. Pan was clean as a whistle. KimSo how is longevity of aluminium drums? Do they get wear marks from steels inside? Whats your experience?
I only knew of a couple racers with alum drums. They said no problems with over 400 runs in 10 second cars. Mine had over 200 runs when I pulled the pan to have a look see. Pan was clean as a whistle. Kim
The guy local I bought my transbrake vb from had one too, but this is a street car so i want bullet steel for it when I do upgrade. Always thought a bolt in sprag was to replace a no good sprag? This trans was completely apart, all checked with a few parts added here and there. I know its not going to last, but it will get me going for now on a build that is yearssss in the making at this point.I have a used billet aluminum one on the shelf that I’ll sell. Just sayin.
I will also say, I’ve seen many stock units with turbo action valve bodies (non LBA), 5.0 levers, rigid front band, and deep pans last a looooong time in 10 second cars, one in a 9 second car. No bolt in sprags, no billet drums, no low band apply. Knock on wood never saw an issue. Then everyone started building more power and upgraded.
The guy local I bought my transbrake vb from had one too, but this is a street car so i want bullet steel for it when I do upgrade. Always thought a bolt in sprag was to replace a no good sprag? This trans was completely apart, all checked with a few parts added here and there. I know its not going to last, but it will get me going for now on a build that is yearssss in the making at this point.
The ultimate sprag bolts into the case through the rear support and two additional bolts. That helps hold the outer cam in the case opposed to the stock set screw and press fit. The 16 elements also have more holding power than a 12 or 14 element bolt in sprag. Not that the 6 bolt 16 element sprag cant fail, but it’s considerably stronger than a stock sprag or a 4 bolt 12 or 14 element sprag.
I don’t blame you for wanting steel. That is the way to go in my opinion especially in a street car.
It may last longer than you think, especially with a lot of street use.
Thanks for clarifying about the sprag stuff. I knew about the Ultimate Sprags, but I guess I was just thinking of the plain bolt in units.
Yea this is a street car first and foremost, but I would like to run it in a few of the daily driver no prep classes here, so it will have to withstand some actual racing abuse.
With my luck, I will barely get it running this season and not get much racing on it, so maybe next winter I can get the trans built up properly.
What do the parts you listed in the beginning of this thread cost roughly? Not labour, just hard parts? I have done all my own transmission work up to this point, so I think i'd be fairly comfortable installing better parts so long as no special machining is required to do so.
The ultimate sprag bolts into the case through the rear support and two additional bolts. That helps hold the outer cam in the case opposed to the stock set screw and press fit. The 16 elements also have more holding power than a 12 or 14 element bolt in sprag. Not that the 6 bolt 16 element sprag cant fail, but it’s considerably stronger than a stock sprag or a 4 bolt 12 or 14 element sprag.
I don’t blame you for wanting steel. That is the way to go in my opinion especially in a street car.
It may last longer than you think, especially with a lot of street use.
Thank you for that break down! I have some of those parts in my current build already, so subtracting those, I need about $5,200 worth of parts for my 727 to be as bullet proof as possible...Better start saving now!Billet steel big piston front drum is $795
Or
Billet aluminum big piston front drum $695
Ultimate sprag is $220
Trans brake valve body $695 plus $75 core
Footbrake valve body is $395 plus $75 core
4 pinion billet steel Front planetary machined for Torrington bearings with billet aluminum 4 pinion rear planetary machined for Torrington bearings, rear support with roller bearing, steel low/reverse drum with roller bearing, steel park gear with aluminum governor sleeve $1,075
Billet aluminum rear drum $450
Billet aluminum forward piston .825” tall $95
Bellvue spring $25
Billet aluminum dual ring dual spring servo $145
Billet aluminum low/reverse servo $95
Billet steel 4.2 second gear lever $70
Heavy duty band strut $35
Solid 2nd gear band Kevlar lining with grooves, 2.2” wide model $160
Low/reverse band Kevlar with grooves $45 plus $35 core charge
Deep cast aluminum pan kit with billet filter extension, re-usable pan gasket, Dacron filter, and pan bolts $185
Hardened wide lug front pump gears with calico coating $250
Modified front pump support $175
300m input shaft with billet steel hub $895
300m output shaft $895
Lightened sun shell with holes $225
Rebuild kit with red clutches and regular steels $170
Teflon sealing rings $15
Accumulator blocker $10
I changed out some of the parts listed in the original post such as the low/reverse drum being aluminum and park gear being aluminum.
Thank you for that break down! I have some of those parts in my current build already, so subtracting those, I need about $5,200 worth of parts for my 727 to be as bullet proof as possible...Better start saving now!
And no, I am not being sarcastic, as I regularly see well built glides and T400s selling on marketplace local to me for between 4-7k in used or freshly built. Too bad there aren't many mopar guys who enjoy going fast around here, otherwise I may be able to snag a 727 fully built for a decent price.
I've been talking with miszny on some parts to achieve some better longevity with his 727, and we'll get there at some point if some parts would show up.
I've learned quite bit over 25 years on what you can get away with and what you cannot in certain 727 combinations. 727 hard parts are fairly strong, but when you add forced induction, nitrous and transbrakes, etc. things can and typically will break.
Last year I was asked by a good customer to build him a new 727. He was going from a stroker 440 to a gen 2 stroker hemi that made about 950hp on the dyno. He wanted a footbrake 727 rated to 1000hp. We ended up building a transmission with billet steel drums, billet steel planetaries and both 300m shafts. We figure it's good to well over 1200hp. I tend to overbuild my transmissions as to not get that phone call, and I historically have a very low failure rate. This transmission with a converter was not cheap.
The goal is to only see these things back every so often for freshen up, and upgrades--if they were not done on the initial build for whatever reason, usually a budget thing. The goal is to not have to fix a heavily damaged transmission--that is the reason for building it right the first time. ($$$)
Well, here's another example and a new rule I had to put in place several decades ago. Got asked to build a small block 727 for a mild 360 with a procharger and a very small amount of boost. Street car mainly. No big deal I thought.. high pressure reverse manual valve body, good servos, clutches and bands and she's down the road Well, it ripped the input shaft out of the hub. Which then required a new rule--If I was to build a transmission for a forced induction application it got a 300m input shaft and billet hub. I've never seen a 727 input shaft actually break, just rip out of the oem hub. I've never seen an oem 727 output shaft break either and we've used them in blower combinations over 1000hp. However, any serious effort blower combination gets a 300m input and 300m output as to not have a failure.
Had a car this last summer have a strange failure. Super gas car, and the customer insisted on using a SB727. Ok, with gear ratios and 1st or 2nd gear launch we can make something work. 430" W9 small block making 750hp or so, heavier older build tube chassis Daytona. Transmission worked very well for several years and went 150mph on the throttle stop.
With about 200-300 runs on it, at the last mile high nationals, out of the burnout box the transmission goofed up. He pulled to the prestage beam, and the transmission was locked up completely. We didn't know what was wrong at the time, and as the transmission builder, I was hoping for a differential failure. It was not the case, unfortunately for me and we got it to my shop to tear down and have a peak. The transmission looked perfect inside, but the forward clutch was locked on. The piston was not popped out of the bore, the clutches weren't even burned. So I look closer and noticed the forward drum was cocked on the input hub. The billet drum had cocked and broke some of the small retaining teeth off at the end of the input hub splines. It was cocked enough to keep the forward clutches on and lock up the transmission. Running a tight fwd clutch clearance and the fwd drum riding up over those retaining teeth on the one side was all it took to lock the clutch on. Pics attached...
So, of course we came up with a new rule. 750hp and above N/A now gets a 300m input and billet steel input hub. Yep, it sucks ($$$), but I don't want THAT phone call again..
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