47RH...drum questions

BLT4SIN

BLT4SIN

New member
Joined
Jan 6, 2013
Messages
259
So im puttting together my trans for my 95 12v. single cab 4x4 moderate power id say 450hp modestly. its a not a daily driver but is a tow rig and weekend wheeler/drag strip.
well so far ive gotten triple disc tc, alto clutchs koleen steels sonnax servos 5.1 lever transgoshift kit,larger o/d spring....etc.

my question is can i machine my reaction plate in my forward drum to allow clearance for an extra clutch and steel?...(im usinf the thick clutchs and steels not the thin).. my idea is to machine the round edge of the reaction plate which presses against the belleville spring to gain more clearance.
 
Why not just run thinner steels/clutches? Way easier and you don't have to worry about keeping the integrity of the drum (depending on how much material you're talking about removing)
 
Ive been told with towing that i dont want to use the thinner kit.... plus i would machine just the reaction plate not the drum or piston itself? just a thaught
 
maybe .140 outa the rolled side of the reaction plate///...wondering if anyone has done this
 
I tow with mine, thinnest pieces we could find and keep within spec. Last time the Trans was apart they looked like new. Good valve body is key also.

For your original question, I'd say you you could machine off .00X, but I'd be worried about .XX,

I'd also wait for a 2nd opinion, I'm no expert.

Sent from my DROID RAZR using Tapatalk 2
 
Last edited:
I would stick with .084 cutches and steels in direct drum. Its ok to use a thin steel on the piston, but thats the only spot i like to use them. Its ok to machine the reaction plate, i just wouldnt go less then .125 on the lip that catches the snap ring.

On edit. Just re-read it and saw you said forward drum. No need to put more then 4 in there. Its not a shifting clutch pack so no need for thick clutches either. I would add one to direct and OD brake and call it good.
 
Last edited:
For that use I wouldn't think that you would need to go that in-depth. I built my 47re with new stock clutches. It's held 630hp on the dyno and daily driving at 450hp for 45k. Also has taken numerous 40lb boosted launches and even outlasted my Dana 60 on one of them. My philosophy is if it ain't broke don't fix it. For your application just surface it a little if it has some imperfections.
Sean
 
the valve body is the stock unit w a transgo shift kit...the tfod hd one? that was professionally done by a trusted builder i use.. and i do agree that i dont want to take to much out of the reaction plate i was just thinking while im in there might as well....
ive managed to fit 4 of the .084s in used a reaction plate..di the same to direct drum and got 5 with proper clearance of course..

i appreciatte the replies as i am tired of this truck being a trans eater i just wanted to do it right the first....this time lol
 
has anyone played with drilling the direct drum for quicker evac of fluid and also drilling a secondary fill hole? i saw a member on here had done it but didnt see any feed back? i do plan in the future to push the power up maybe 650-700 during summer so wana build this trans to survive pulling 12k at a detuned 500hp..."eventually"
 
Nearly every transmission that I've opened up that the previous builder machined the reaction plate to fit 5 clutches has had the 5th clutch inner splines bound up from slipping off the end of the planetary that it rides on.

Lavon
 
LAmiller said:
Nearly every transmission that I've opened up that the previous builder machined the reaction plate to fit 5 clutches has had the 5th clutch inner splines bound up from slipping off the end of the planetary that it rides on.

Lavon
Click to expand...

Let me ask you this, although it has a broken input shaft the tranny, my 98 has a stock drum with DTT internals form 2003.....I know crazy huh! It has (3) 84's and (2) 93's for clutches. One of the things that I ran into after running it for quite a while was going from fwd to reverse, it took a bit for it to release and engage. Other than that and a yearly fluid/filter change with nothing but clutch fuzz on the plug it was great till the billet shaft snapped.....somewhere in the 60-70K mile range.

Jim
 
I was talking about the forward pack , not the direct. If your talking about the forwards where was clearance machined? I have had good results from adding an additional clutch to the direct drum.

Lavon
 
Last edited:
was the inner clutch slipping on the inner side or outer? closer to piston? ive seen that but only once so im wondering if its even worth it...would it do more damage then help? im an engineer not a tranny builder so the experience and advice is appreciatted...
also has anyone considered machining the direct drums piston just a shade?????Just food for thaught..

i am running the stock shafts for now but i do plan on purchasing precision 300m input.
 
LOL..............

LAmiller said:
Nearly every transmission that I've opened up that the previous builder machined the reaction plate to fit 5 clutches has had the 5th clutch inner splines bound up from slipping off the end of the planetary that it rides on.

Lavon
Click to expand...

Including mine from HTS.........LOL
 
The input has nothing to do with forward clutch clearance, run the oem 4 clutch setup with sufficient line pressure and a good Bellville spring and your forward clutch will live a long happy life at high hp. Running 5 forward frictions will usually cause premature failure since the extra clutch will come off the end of the planetary splines once there's some wear on your frictions.

Lavon
 
Post #6, good advice, get an extra clutch in there but don't sacrifice steel thickness as thin steels warp in high heat cconditions.

Lavon
 
any ideas on drilling it for quicker fill and evac... also anyone ever machined direct drum piston down
 
You must log in or register to reply here.
Back
Top