New best results in broke parts

wvdodgemirada

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Car was running great, new bests for the car went 12.39 12.43 and then 12.392 on a 12.40 dial in for round one exit. and boy the car let me know it wasn't happy. lol obviously car went through traps and heard a bang followed by rattling under the car...this aint good. car shut off and made the turn off the track, the only good thing is they were only down for 10 minutes for the clean up. We are in belief that the trans yoke let go, which caused all the damage. but if any one has ideas please chime in. ill know more when I get the car up in the air later this week. The u joint was a solid spicer that was put in last year. Some pictures of carnage.

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Justwondering

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Jbweld? Are you sure you can't fix it cheaper with gorilla tape? Then you'd have money in the budget to get a fresh can of rustoleum to pretty it up.
 

BudW

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My Pa always said you are on the right path, when you keep breaking different things (as each past break gets upgraded). He went on to say those people who don’t break parts are not pushing their cars.

One thing I noticed is there is not much (or any) grease on the U-joint needle bearing surface. I suspect the lack of grease for U-joint could be a cause of failure.

The old joint caps are missing. If U-joint got installed without the retaining clips, one (of the caps) could have worked loose and out, once an imbalance occurred under WOT the yoke gave out.

I can’t tell by the photos if the yoke is cast or forged from where the loops broke at. If a "cast part" breakage would show a coarse casting (so to speak) at the breakage.
A forged part generally show (if not beat to death) would stretch before breaking. One corner shows to be beaten to death, so that corner can’t be used to tell.

The extension housing has a couple of shiny areas at the breakage – which might mean it has been cracked for a while, possibly. Any imbalance at WOT will beak those extension housings without thinking twice about it.

If this is a 727 transmission, Dodge made a heavy duty version tail housing that helps these problems. The snap ring cover is on side of housing instead of under the transmission mount (the way to tell if you have a HD housing).

Need better pictures with better lighting, to tell you anything more.
 

wvdodgemirada

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Few things I should've added, it is a 904 trans.
The extension housing has a couple of shiny areas at the breakage – which might mean it has been cracked for a while, possibly. Any imbalance at WOT will beak those extension housings without thinking twice about it.
we had a similar thought on it possibly already being cracked. Also the retaining clips were used on the install of u-joint. As far as yoke goes it was the original to the car, so id assume it was cast? Be more than happy to supply better pictures if you want, just got car up in air today, just let me know what you wanna see. Cause I could use a hand debunking what happened, another idea we are tossing around is the bearing let go which allowed the yoke to move more?
 

BudW

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The transmission output shaft bearing is a tough part to damage or fail - so I doubt that is it. On the other hand, if the output housing has been cracked for a while, it could have allowed a lot more movement that might have contributed to this issue.

I have seen yokes be both forged and cast. I think the older ones were all forged and fairly sure that pretty much all of the newer ones are cast - but I’m not going to take that thought to the Vegas. I do know the 727 yokes are thicker/stronger than 904 ones are.

Before going back together, make sure the output shaft is not bent. It may have to be removed from transmission and placed on an bench much like what they use to balance things (see picture).

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wvdodgemirada

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Finally got trans back in the car. Needed new output shaft, and list of other parts. Wasn't to bad though.
 

BudW

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Those shafts are not easy to bend - but i've seen a few bent ones - and they cause a lot of problems until narrowed down as to what the cause is.
 

wvdodgemirada

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The final piece was installed today. Nice 3.5 aluminum driveshaft with 1350 u joints. Took car out for small spin, about a mile and all seems well.

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BudW

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Smiles - in the picture, it looks like a large toothpick.

I like aluminum for driveshafts. I just don’t like paying more for an aluminum shaft.
But hey, you have the bigger 1350 joints now, which is cool.

BudW
 

Locomotion

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FWIW, I've been running solid 7260 Spicer u-joints in my Dart at mid-low 11's for years with a 1.47 60' best. Same joints in the wagon, but it's down with engine issues after a mid-12 second debut. 1350's do offer extra insurance.
 
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