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Re: 727 Trans is Broke ! [Re: emarine01] #1399566 03/11/13 07:51 PM 03/11/13 07:51 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Can someone explain the series of events that causes a sprag failure. When you load the sprag then spin(which you unload the sprag, it can back the rollers up) then load it again(traction) you slam the rollers forward again... it doesnt like that free play and it has momentum to really hit them hard and go over the ramp

Re: 727 Trans is Broke ! [Re: 440Jim] #1399567 03/12/13 11:42 AM 03/12/13 11:42 AM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH Taking time off to work on my car
BradH Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Quote: The repaired transmission is back in the car now. Good thing I had spare parts and gaskets, rings, etc.

Re: 727 Trans is Broke ! [Re: MR_P_BODY] #1399568 03/13/13 12:21 PM 03/13/13 12:21 PM
Joined: Jan 2007 Posts: 3,695 nc E emarine01 master
emarine01 master E Joined: Jan 2007 Posts: 3,695 nc	Quote: Quote: Can someone explain the series of events that causes a sprag failure. When you load the sprag then spin(which you unload the sprag, it can back the rollers up) then load it again(traction) you slam the rollers forward again... it doesnt like that free play and it has momentum to really hit them hard and go over the ramp Thankx Mike... Is this still true if the low rev band is applied? or just 1st gear sprag only? We run a stock VB out of drive with a 5k vert... We spin all 4 wheels that weigh between 400 to 600 lbs depending on tire size for the first 2/10 of a second before the trans will auto shift 2nd , the first 2/10s is all spin the truck launches when we hit 2nd gear then still spinning shifts into 3rd which spinns for the rest of the 200ft, the wheels never catch up to the truck, Is there a better / safer way to do this?

Re: 727 Trans is Broke ! [Re: emarine01] #1399569 03/13/13 01:46 PM 03/13/13 01:46 PM
Joined: May 2003 Posts: 6,571 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,571 Downtown Roebuck Ont	LBA manual VB and an air shifter? Kevin

Re: 727 Trans is Broke ! [Re: Twostick] #1399570 03/13/13 08:21 PM 03/13/13 08:21 PM
Joined: Jan 2007 Posts: 3,695 nc E emarine01 master
emarine01 master E Joined: Jan 2007 Posts: 3,695 nc	So there is no way to apply the lo band the in the drive position? I need to rethink this sprag failure mode thing some, We have not trashed any sprags yet racing, is it possible that there is enough load on the sprag while spinning that it does not release... tire weight + transfer case and 2 drive shafts & 2 ring and pinions... axles....ect... We put enough power to the ground to pull the front wheels off the ground in the mud so it hits some traction wile spinning but it never dead hooks.

Re: 727 Trans is Broke ! [Re: emarine01] #1399571 03/13/13 09:19 PM 03/13/13 09:19 PM
Joined: Jan 2003 Posts: 5,444 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,444 Indiana	Emarine01, I asked Rick Allison about: Running a stock VB and I wanted to leave my 727 in D all of the time and I wanted to hammer on it whenever I wanted. What upgrades do I need? Rick suggested that I use his Ultimate Sprag on my street setup. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: 727 Trans is Broke ! [Re: YO7_A66] #1399572 03/13/13 11:11 PM 03/13/13 11:11 PM
Joined: Jan 2007 Posts: 3,695 nc E emarine01 master
emarine01 master E Joined: Jan 2007 Posts: 3,695 nc	Thankx Dave, We run a HD bolt in sprag of some kind, don't remember which one, This goes back to my question from last week, Is it better to run lo range in drive and let it up shift or run high range in low gear and no shifting, my final wheel speed is close to the same MPH either way,

Re: 727 Trans is Broke ! [Re: emarine01] #1399573 03/13/13 11:25 PM 03/13/13 11:25 PM
Joined: Dec 2004 Posts: 1,489 St. Louis Mo. 10 o to go "Happy Don"
10 o to go "Happy Don" Joined: Dec 2004 Posts: 1,489 St. Louis Mo.	Quote: Thankx Dave, We run a HD bolt in sprag of some kind, don't remember which one, This goes back to my question from last week, Is it better to run lo range in drive and let it up shift or run high range in low gear and no shifting, my final wheel speed is close to the same MPH either way, Their is a replacement sprag same stock or the heavy one is the 16 roller sprag Coan super sprag or the ultimate sprag I think AnA sells . I have the 16 rollers in now hoping to save cases . 7625205-BKD9-11-01_302C.jpg (31 downloads) 2009 418" build dan smith built new 9.96 131.82 6.23 108 1.30 60 foot best to date 9/15/09 8in 727 430 dana 2860 lb 3040 lb w driver

Re: 727 Trans is Broke ! [Re: 10 o to go] #1399574 03/14/13 09:51 AM 03/14/13 09:51 AM
Joined: May 2008 Posts: 1,238 North Cackilacky S sdaurity pro stock
sdaurity pro stock S Joined: May 2008 Posts: 1,238 North Cackilacky	I have reapired a half dozen 727's with broken outputs over the years. One day I will have something cool here.

Re: 727 Trans is Broke ! [Re: sdaurity] #1399575 03/14/13 12:56 PM 03/14/13 12:56 PM
Joined: Jan 2003 Posts: 16,934 NC 440Jim OP I Live Here
440Jim OP I Live Here Joined: Jan 2003 Posts: 16,934 NC	I didn't realize the output shafts broke with any regularity at power levels less than 800hp. But in my case, I believe it was a shock loading issue when the rear gear broke, and jammed while under full power, in 1st gear (torque multiplication). I replaced the U-joints also as a preventive measure, even though I didn't see any obvious cracks and the roller bearing surfaces didn't show any marks (NEAPCO Brute Force U-joints).

Re: 727 Trans is Broke ! [Re: 440Jim] #1399576 03/14/13 02:01 PM 03/14/13 02:01 PM
Joined: May 2003 Posts: 6,571 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,571 Downtown Roebuck Ont	I think that is what engineering types call a classic shock load fracture. Kevin

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