Allison 5sp: Some bad trans damage.. Whad i do wrong?

AubleAK

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Aug 4, 2011
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ImageUploadedByTapatalk1334566255.535671.jpgImageUploadedByTapatalk1334566266.414045.jpgImageUploadedByTapatalk1334566280.239417.jpgGmax 3, 2000 miles. Shifts great. Started making noise and limping aloy. Cut the filter open, And not to my surprise metal in it. C1/c2 clutch hub was rubbing on the c3 backing plate. Any ideas why this would happen? Also, the shaft im holding had more play in it then i think it should. About 3/8 inch. Thanks in advance.
 

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IOWA LLY

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Feb 23, 2007
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A missing or severely damaged torrington bearing would allow the front rotating assembly (C1/C2 housing) to slide "back" into the C3 back plate. I have fixed several like this. Almost always caused by someone trying to install an extension housing while the trans is still in the truck and having a torrington bearing fall out of place. Have you pulled the rear half apart yet?
 

AubleAK

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Aug 4, 2011
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A missing or severely damaged torrington bearing would allow the front rotating assembly (C1/C2 housing) to slide "back" into the C3 back plate. I have fixed several like this. Almost always caused by someone trying to install an extension housing while the trans is still in the truck and having a torrington bearing fall out of place. Have you pulled the rear half apart yet?

I took the tail off, just glanced inside to see if any damage had been done to my clutches. Trans was completely built on the stand. Bearings looked seated at a glance. Havent got into it very far tho.
 

Mike L.

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Looks like the P2 ring gear did not catch the last C3 clutch plate and jammed it into the C3 pressure plate. Notice the melted platice bunpers and the top C3 friction. The top C3 friction is bowed and glazed pretty bad. Doesn't look like it is supported on the splines. Pictures can be decieving.
 

MACKIN

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Aug 14, 2006
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A missing or severely damaged torrington bearing would allow the front rotating assembly (C1/C2 housing) to slide "back" into the C3 back plate. I have fixed several like this. Almost always caused by someone trying to install an extension housing while the trans is still in the truck and having a torrington bearing fall out of place. Have you pulled the rear half apart yet?

Are you talking about the thrush bearing ,thats what I refer to it that goes in just before you drop the c1/c2 rotating assembly in? If so if you put it in backwards also catastrophic failure will occur also. Don't ask how I know that.

For the record It wasn't I who put it in backwards. ;
 

Mike L.

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Are you talking about the thrush bearing ,thats what I refer to it that goes in just before you drop the c1/c2 rotating assembly in? If so if you put it in backwards also catastrophic failure will occur also. Don't ask how I know that.

For the record It wasn't I who put it in backwards. ;

Who was it?
 

PureHybrid

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Feb 15, 2012
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Judging by his location.... :D Performance Innovations? Me and my brother just pulled one apart from them that had 100mi on it and the C4s were burnt because the apply piston bleed hole was installed at ~4 o'clock.
 

Mike L.

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Judging by his location.... :D Performance Innovations? Me and my brother just pulled one apart from them that had 100mi on it and the C4s were burnt because the apply piston bleed hole was installed at ~4 o'clock.

Keep looking. The hole being at 4 oclock didn't burn them up. The pistons are known for rotatating and sometimes wind up at that location without problems. That doesn't mean it should be there.
 

Mike L.

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is it absolutely necessary that the bleed holes are at 12 o'clock? if so why is that? just curious.

The only time the clutch is lubricated is when the piston is applied. We want the lube hole at 12 oclock so that it squirts down on the clutches as much as possible. If the hole it too low the fluid just dumps to sump without helping lube the clutches.
 

MACKIN

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Aug 14, 2006
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Who was it?

Well as you know I was one of the very early on 'test money pit schmucks' to get everyone else where they are today. It was good times and it was bad times.

I still have a box here full of tried parts.

I'm not gonna name names not sure he even participates on these forums anymore but it was somebody I meet at the GTG's that was a transmission guru. Did a lot with Grand Nationals and was very good at it. So he wanted to build my Allison and since I was no transmission guy I was ya hoo sign me up!

I put my faith in him and well you know crap happens crap happened mistakes errors and I took a lot of heat and criticism which ultimately got me pissed off and others pissed off directing my anger towards the developer of said parts (may he rest in peace, I did make peace thankfully and apologized prior to his passing ) not wanting to throw someone who was helping me (not free mind you) who actually made the errors under the bus. I lost a lot of money sum 9-10 years ago. :mad:

Live and learn ,thats who. :D

Doesn't matter now.
 

i_keyser

DD n00b
Jun 4, 2010
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The only time the clutch is lubricated is when the piston is applied. We want the lube hole at 12 oclock so that it squirts down on the clutches as much as possible. If the hole it too low the fluid just dumps to sump without helping lube the clutches.

gotcha, thanks Mike :thumb:
 

PureHybrid

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Feb 15, 2012
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Keep looking. The hole being at 4 oclock didn't burn them up. The pistons are known for rotatating and sometimes wind up at that location without problems. That doesn't mean it should be there.

Thanks Mike, Ive never heard of them rotating. Everything else checked out ok BUT the c4 pack did have the inner-most friction distorted on the splines TOWARD the c3 pack (I A$$umed it was from a crooked application of the piston). I would think that if the planetary wasnt engaged all the way into the c4's we would have seen other damage...?
 

Mike L.

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I havent. I only got the bell housing off to look inside quick, and found the problem. I should have an update this weekend when i get back home and go thru it.

You haven't found the problem yet. You've only found part of the reults.