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Re: Tranny Explodes
[Re: terzmo]
#1024662
07/02/11 06:14 PM
07/02/11 06:14 PM
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Joined: May 2003
Posts: 13,202
aZLiViN
J_BODY
I Live Here
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I Live Here
Joined: May 2003
Posts: 13,202
aZLiViN
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Quote:
..took off and spun the tires...driver let off and the tranny blew like there was 5 pounds of C4 in it...
Tires may have hooked and unhooked.... hard on the roller clutch. see what condition it's in when you disassemble. Stock front drum I'm assuming? Time for an aluminum or aftermarket steel drum. and as mentioned, a shield or blanket is a must. Same thing happened to a friend of mine with a low 11 Challenger. In his case the rear gear broke, shocking the rear roller allowing it to lock which spins the front drum to the point of..... well, you've been there now.
....and pop the rear cover and check the ring gear just to be safe.
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Re: Tranny Explodes
[Re: topside]
#1024663
07/02/11 06:14 PM
07/02/11 06:14 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
master
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master
Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
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Do a search on here you would have quickly found the cause.
Funny how a GM guy will listen to the warnings involved with their race parts. But, a hardheaded Mopar guy will ignore and keep going then wonder what happened when something goes wrong.
You overrun the clutch (AKA Sprag) and the front drum revs into the twilight zone. Boom it explodes. It's not the 727 as a stock one in low gear will not blow up.
It is the aftermarket parts that allow the rear drum to spin free expecting the sprag to hold it as they do not apply the rear band in low. Bolt-in sprag, still same problem.
A rear band apply valve body is the way to go. Many manual valve bodies are not. When building that 727 instead of wasting money on parts you do not need spend $500 on a billet front drum that will not explode. I know someone that blowed one but still will not buy the drum. And a no low band apply valve body.
Senseless. But, it is the 727's fault people build these trannies every day like this.
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Tranny Explodes
[Re: Leon441]
#1024664
07/02/11 06:44 PM
07/02/11 06:44 PM
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Joined: Oct 2008
Posts: 492
South Jersey, NJ
DragDart360
mopar
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mopar
Joined: Oct 2008
Posts: 492
South Jersey, NJ
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NHRA rules require a transmission shield any quicker than 11.00
I just put a CSR shield in my Dart as I expect to run low 10's.
It's the best $300 you can spend. 904 behind a small block, bolted right up.
70 Dart Swinger, 2850 lbs
SB 408, Bullet roller 264/268 @50 .636 SSDS stage 2 Edelbrock heads, 1 7/8 Headmans, 1050 dominator by Dom, 9.867 @ 133
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Re: Tranny Explodes
[Re: terzmo]
#1024669
07/02/11 08:38 PM
07/02/11 08:38 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Just built a drag car... has a new 512 stroker motor....indy heads...727..low gear kit,manual valve body..dana..4 link suspension...33 by 17 tires.Ran a best of 10.28 so far...Car did a burnout fine...came to line..took off and spun the tires...driver let off and the tranny blew like there was 5 pounds of C4 in it...tail shaft and converter survived but the case is in a hundred parts....as everything in the case....went through the floor..broke the drivers foot in 3 places....
What would/could cause this ?
As soon as he let off in first gear at high RPMs is
when it killed the sprag/over running clutch and
then it spins the drum 2.2 times faster than the
engine RPMs... centrifugal force did the rest...
all you have to know on those trannies is not to
let off in first gear at high RPMs... SHIFT to second
then let off(over running clutch isnt in play then)
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Re: Tranny Explodes
[Re: cudadoug]
#1024671
07/02/11 09:15 PM
07/02/11 09:15 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Just what Mr. P body says. 
GET A BLANKET OR A SHIELD!!!!!
Wait a second. How does a 4-link car with a funny car tire SPIN...??
Simple... pump them up like a basket ball
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Re: Tranny Explodes
[Re: dOc !]
#1024672
07/02/11 09:23 PM
07/02/11 09:23 PM
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Joined: Mar 2005
Posts: 2,060
Pendleton NY
terzmo
OP
top fuel
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OP
top fuel
Joined: Mar 2005
Posts: 2,060
Pendleton NY
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Quote:
An alum drum or LBA valve body would have prevented this ... 
Can You explain LBA valve body....thanks in advance
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Re: Tranny Explodes
[Re: hemigod426]
#1024674
07/02/11 10:48 PM
07/02/11 10:48 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
did he not have a bolt in sprag? first gear burn out? slipped out of gear?
Bolt in sprags will break also... they are for a loose
race in the housing... unless its a super sprag with
lots of rollers
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Re: Tranny Explodes
[Re: hemigod426]
#1024675
07/02/11 10:49 PM
07/02/11 10:49 PM
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Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
dartman366
I Live Here
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I Live Here
Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
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Quote:
did he not have a bolt in sprag? first gear burn out? slipped out of gear?
bolt in sprag will not remotely help in preventing an explosion, it is simply a fix for a damaged case, they do have some out that have improved holding ability but still they are not the end all be all of preventing a explosion,,LBA valve body and proper use during burnouts (second gear start) and driving charicteristics is the way to make them live. 
Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.
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Re: Tranny Explodes
[Re: dartman366]
#1024676
07/02/11 10:53 PM
07/02/11 10:53 PM
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Joined: Aug 2003
Posts: 11,179
Atco NJ
DJVCuda
I Live Here
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I Live Here
Joined: Aug 2003
Posts: 11,179
Atco NJ
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Quote:
Quote:
did he not have a bolt in sprag? first gear burn out? slipped out of gear?
bolt in sprag will not remotely help in preventing an explosion, it is simply a fix for a damaged case, they do have some out that have improved holding ability but still they are not the end all be all of preventing a explosion,,LBA valve body and proper use during burnouts (second gear start) and driving charicteristics is the way to make them live.
That combined with an aluminum / billet steel drum to prevent the hand grenade from going off.
To answer the OP - The drum exploded, you had the stock cast iron drum in there and you need to call John Cope and get a billet or aluminum drum in your next tranny.
The super sprag or at least a bolt in unit will prevent things from going bad as well, but the drum is what exploded.
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Re: Tranny Explodes
[Re: DJVCuda]
#1024677
07/02/11 11:03 PM
07/02/11 11:03 PM
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Joined: May 2004
Posts: 12,410
Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
Posts: 12,410
Taxes & Virus's R-US, NY
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Quote:
Quote:
Quote:
did he not have a bolt in sprag? first gear burn out? slipped out of gear?
bolt in sprag will not remotely help in preventing an explosion, it is simply a fix for a damaged case, they do have some out that have improved holding ability but still they are not the end all be all of preventing a explosion,,LBA valve body and proper use during burnouts (second gear start) and driving charicteristics is the way to make them live.
That combined with an aluminum / billet steel drum to prevent the hand grenade from going off.
To answer the OP - The drum exploded, you had the stock cast iron drum in there and you need to call John Cope and get a billet or aluminum drum in your next tranny.
The super sprag or at least a bolt in unit will prevent things from going bad as well, but the drum is what exploded.
We found parts of the sprag and the drum in the car. Litterally, one of the sprag bearings went thru the floor like a bullet, left a hole just like one. Other parts were larger and it could have been really bad. I talked with Paul today, and even though he doesn't feel lucky, I told him some of the stuff we found in the car.
The trans is toast, but all the parts to put a new one are in. It will have a sheild & a super sprag. The floor boards on the other hand are a real mess. Its going to take some sheet metal work to fix.
It spun off the line due to a bad burn out procedure which seems to be because the line lock button was moved and its not comfortable were it ended up. It is being moved before I climb in...
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