abodyjoe
Well-Known Member
if i ever run a 727 again two parts it will be sure to get are the billet drum and an ultimate sprag. my legs and life are well worth the extra cash. nuff said.
Is this issue only with 727's or do the 904's do this also?
Ted
I hear you, but the fact is, the manual valve body is really all that's needed on 90% of the stuff out there. That and a little common sense.
Actually it was the Manual Valve Body with no low band apply that started the drum explosions.
Actually, no it was not. The low band apply will not stop the transmission failure. The only way to stop or drastically cut back the failure is any manual valve body and doing burnouts in 2nd gear. The baddest assed low/reverse band in the world will not stop a 727 drum explosion in extreme situations. Just like a bolt in sprag will not. Read up on how fast the front drum spins. There's no amount of low band apply that will stop it. 2nd gear burnouts will. The low band apply is totally meaningless if you do the burnout correctly in 2nd gear, because the low band is not even applied in 2nd.
Some of us don't make enough power to start a burn out in second without a line lock or water or both. LOL
Some people don't use a line lock, a line lock is more a must in a stick car.
The 727 is one of the best transmissions made. Period. The problem with transmission explosions is one thing. Operator error. Installing a manual valve body and eliminating doing the burnout in first gear will completely eliminate the problem. No need for a bolt in sprag, although it is a nice addition. The fact is, that if you do the burnout in first gear and shift into second and the tires hook shifting into second the shock will rip even a bolt in sprag out and the transmission will likely still explode. Simply doing the burnout in second gear will all but eliminate the problem.
People will argue with this till they are blue in the face, but a bolt in sprag is not necessary. It will do nothing to keep the explosion from happening. It will simply make the carnage less.
The failure occurs when the front drum RPMs become so great, the outside or the shell flares out and locks against the case. When this happens, it doesn't matter what kinda sprag you have, that transmission IS comin apart.
Since it is harder to spin the bolt in sprag out of the case because it is bolted in, it absorbs more of the shock of the explosion. In other words, it takes more to tear it out of the case......but it WILL tear out.
It's easy to see in any 727 explosion the kinda force that's dealt with. A bolt in sprag will NOT stop it. It will slow it down. I am sure there have been instances where a 727 with a bolt in sprag didn't come completely apart, but in those cases, the explosion was not as violent......probably because the sprag helped hold it together, or the RPMs were not quite as high as other failures.
The reason the transmission fails has NOT ONE THING to do with the sprag. The reason for the failure comes from doing burnouts in first gear and having the tires hook up on the 1-2 shift. The resulting shock is what causes the transmission failure.
A manual valve body will totally eliminate the entire problem IF the operator will simply do the burnouts in 2nd gear. NOTHING else is required. No bolt in sprag, nothing. They are a nice addition, but the only one thing that stops the failure is the manual valve body that allows 2nd gear burnouts.
more fun with 727s
the 904 doesn't seem to have the problem. probably because its not as bug. the 727 is a freaking tank. i'll stick with a 904.
It was totally unheard of until the aftermarket did away with the low band apply.
Engine speed needs to exceed 6000 rpm in first gear with a failed sprag and no low band apply before the cast drum comes apart. The drum will spin at 2.2 times the engine rpm in first.
Test have shown the stock cast drum to come apart at 13000 + rpm.
Some of us don't make enough power to start a burn out in second without a line lock or water or both. LOL
If you're running something that cannot smoke tires in 2nd, you probably have something that cannot pull a greasy string outta a cat's *** anyway.