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727 Trans is Broke ! #1399546
03/09/13 02:54 PM 03/09/13 02:54 PM
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440Jim Offline OP
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At the last race of the season the rear end gears broke in my Dart. I put another ring and pinion into the car a few weeks ago when we had a warm (50F) day. It has been cold since then, but today it was 47F at 9:30am, so I pulled the transmission to inspect the sprag for damage.

Well, the sprage was OK. I did straighten two of the tabs that the springs push against since they were not exactly straight. But the surprise was the output shaft was broke in two pieces! See attached. Good thing I have a spare trans to build up.

1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1
Re: 727 Trans is Broke ! [Re: 440Jim] #1399547
03/09/13 02:59 PM 03/09/13 02:59 PM
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440Jim Offline OP
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Here is the other part.
Re: 727 Trans is Broke ! [Re: 440Jim] #1399548
03/09/13 03:04 PM 03/09/13 03:04 PM
Joined: Mar 2004
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SW Ohio
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cgall Offline
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SW Ohio
Holy shnikies, good thing you checked it out. Does the converter look OK?
Re: 727 Trans is Broke ! [Re: 440Jim] #1399549
03/09/13 03:22 PM 03/09/13 03:22 PM
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nc
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emarine01 Offline
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What caused that? We broke the spline section where it slides into the transfer case last year, Also what would cause the sprag to fail when using 1st gear to do burn outs? You got me thinking about it from my last post.
Re: 727 Trans is Broke ! [Re: emarine01] #1399550
03/09/13 04:20 PM 03/09/13 04:20 PM
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Finland, Europe
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Ck[FIN] Offline
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Nice!!
You dont see that everyday, output shaft cut

-1965 Valiant 9.03s 358cu.in R5P7-
Re: 727 Trans is Broke ! [Re: 440Jim] #1399551
03/09/13 09:54 PM 03/09/13 09:54 PM
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440Jim Offline OP
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Here are the two pieces on the work bench.
Re: 727 Trans is Broke ! [Re: 440Jim] #1399552
03/09/13 09:56 PM 03/09/13 09:56 PM
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440Jim Offline OP
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While it was apart, I decided to change the replaceable bronze bushing in the TCS aluminum front drum. I have a lot of passes on this using a Griner high pressure valve body and the teflon rings they recommend. These rings wear the drum instead of the stator support ring grooves.
Re: 727 Trans is Broke ! [Re: 440Jim] #1399553
03/09/13 09:59 PM 03/09/13 09:59 PM
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440Jim Offline OP
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The bushing was a light press fit in the drum.
I used a 2-ton manual arbor press, and it came out and went back in without excessive force. The trick is to have a well fitting bushing driver. Which I made on my lathe. One end is for pressing it out, the other for pressing it back in.
Re: 727 Trans is Broke ! [Re: 440Jim] #1399554
03/09/13 10:54 PM 03/09/13 10:54 PM
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Cedar Lake IN
CRT Offline
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This out put shaft was out of Josh King's Turbo Duster


Re: 727 Trans is Broke ! [Re: CRT] #1399555
03/09/13 11:46 PM 03/09/13 11:46 PM
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MD
Kevins493 Offline
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I have one that was for my spare trans if you need it. It looks like it might have a bit of runout but I haven't checked real close. It was in the car for the 9.86 pass last fall. This is a reminder of why I shouldn't wait until march to work on the car, lol.
Re: 727 Trans is Broke ! [Re: Kevins493] #1399556
03/10/13 08:33 AM 03/10/13 08:33 AM
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United Socialist States of Ame...
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tboomer Offline
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Jim...Sure glad you caught that before the season started!!

Need your rear end checked out? Contact Grizzly!!
Re: 727 Trans is Broke ! [Re: tboomer] #1399557
03/10/13 09:19 AM 03/10/13 09:19 AM
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Frostbitefalls MN (Rocky&Bullw...
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Quote:

Jim...Sure glad you caught that before the season started!!


If it was going to go, it couldn't have happened at a better time!

8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: 727 Trans is Broke ! [Re: gregsdart] #1399558
03/10/13 09:34 PM 03/10/13 09:34 PM
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440Jim Offline OP
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The repaired transmission is back in the car now.
Good thing I had spare parts and gaskets, rings, etc.

It sucks to find it, but I am happy that I was able to work a couple days and get it fixed and back in the car so quickly. It does give me a feeling of accomplishment to get it done. All those years accumulating spare transmissions from junkyards, learning to do repairs myself, and buying the tools and gaskets, etc. to have on-hand has paid off this weekend.
Re: 727 Trans is Broke ! [Re: 440Jim] #1399559
03/10/13 10:12 PM 03/10/13 10:12 PM
Joined: Nov 2003
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New Lenox IL
cudadon Offline
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Way to go Jim! You always tell people to check the sprag after a driveline break, this a good example why that must be done.
Good luck this year Don

http://i131.photobucket.com/albums/p314/cudadon/BKD6_09_10_191A.jpg
Re: 727 Trans is Broke ! [Re: CRT] #1399560
03/10/13 11:54 PM 03/10/13 11:54 PM
Joined: Feb 2005
Posts: 196
State College, Pennsylvania
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fatman Offline
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This out put shaft was out of Josh King's Turbo Duster

Are 727 output shafts more prone to breakage than inputs ?
Re: 727 Trans is Broke ! [Re: emarine01] #1399561
03/11/13 09:44 AM 03/11/13 09:44 AM
Joined: Dec 2004
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St. Louis Mo.
10 o to go Offline
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Quote:

What caused that? We broke the spline section where it slides into the transfer case last year, Also what would cause the sprag to fail when using 1st gear to do burn outs? You got me thinking about it from my last post.


Rule is never do burnouts in 1st gear ,2nd to high normal procedure.

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: CRT] #1399562
03/11/13 10:31 AM 03/11/13 10:31 AM
Joined: Jan 2003
Posts: 75,125
A Banana Republic near you.
JohnRR Offline
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Quote:

This out put shaft was out of Josh King's Turbo Duster





I have an output shaft just like this one that came out of a 69 Belvedere wagon, with an open rear, that the owner thought it would be a good idea to remove the brake line from one rear wheel and cap it so he would have control over the brakes during the burnout contest at Carlisle one year. when the rear sprag started to roll over the shock snapped the shaft off , he was LUCKY it did that ...
Re: 727 Trans is Broke ! [Re: 10 o to go] #1399563
03/11/13 10:36 AM 03/11/13 10:36 AM
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JohnRR Offline
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Quote:

Quote:

What caused that? We broke the spline section where it slides into the transfer case last year, Also what would cause the sprag to fail when using 1st gear to do burn outs? You got me thinking about it from my last post.


Rule is never do burnouts in 1st gear ,2nd to high normal procedure.



If you have a full auto shift trans you have no choice but to start the burnout in first gear, shifting the trans into low which applys the rear band then upshifting would be the way to go.

I broke the output shaft off in the transfer case of my 2000 Ram building boost against the convertor while foot braking it , the boost went over 20psi before my brain registered to take my foot off the brake pedal. 1000 ft/lbs at 1300 rpm will do that ...
Re: 727 Trans is Broke ! [Re: JohnRR] #1399564
03/11/13 07:17 PM 03/11/13 07:17 PM
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nc
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emarine01 Offline
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Can someone explain the series of events that causes a sprag failure.

Re: 727 Trans is Broke ! [Re: emarine01] #1399565
03/11/13 07:43 PM 03/11/13 07:43 PM
Joined: Jan 2003
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Balt. Md
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383man Offline
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Thats what happens with all the hp Jim. Not only do you hurt the sprag you break the output shaft. Glad you got it fixed so fast. Thats one reason I want to go to a Dana because if I break this 8-3/4 the trans will come out. I have a few output shafts in my garage from all my years at the Dodge dealer but I dont remember what some fit. Many times we ordered output shafts if it needed it or not under warranty. Ron
Re: 727 Trans is Broke ! [Re: emarine01] #1399566
03/11/13 07:51 PM 03/11/13 07:51 PM
Joined: Jun 2003
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Romeo MI
MR_P_BODY Offline
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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
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Val-haul-ass... eventually
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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
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emarine01 Offline
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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
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Downtown Roebuck Ont
Twostick Offline
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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
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nc
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emarine01 Offline
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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
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Indiana
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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
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nc
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emarine01 Offline
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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
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St. Louis Mo.
10 o to go Offline
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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 .

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
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North Cackilacky
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sdaurity Offline
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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
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NC
440Jim Offline OP
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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 Offline
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I think that is what engineering types call a classic shock load fracture.

Kevin
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