727 one bad clutch plate. Input to output washer half gone

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Mopower71

Mopower71

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Need some help.
20211018_195754.jpg

I don't want to just put clutches in and have this happen again.
Bigblock 727. Rebuilt years ago,red alto clutches, kolene steels. all new bushings, thrust washers, both bands, cheeta manual reverse valve body, not a lot of time on it, 50 miles at most, and a few 1/4 mile passes.
Just driving in driveway and lost reverse. The servo cracked. Replaced with billit servo. Pan was clean, no clutch material. New fluid. Car sat and the pan gasket was leaking so I pulled it and found what is pictured.
Pulled trans and found one clutch plate in the front pack disintegrated, the one all the way at the bottom.

Also found the fiber washer between input and output shaft was only half there.
And the edge of the front most planetary gear the edge was hitting and wearing the metal, making metal fragment on the edge.

What would cause just the one clutch to lose the clutch material?
And would the one input to output fiber washer cause the interference and wearing of the edge of the planetary gear ?

Thanks for the help.
 
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ;
Edit; I mean the first plate to be taken out on disassembly.
was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

20220303_143848-jpg.jpg

In the pic below; what is that serrated business just outside the spring clamp? I don't remember any of my hi-drums having that. Is that what cut your planetary? No, I think that is too low. forget it, lol.

20220303_140439-jpg.jpg


I would take that Sunshell outta there and have a look behind it, that planetary looks a lil high. But before you do lift up on the planetary and see how much end-play is on that stack. It better be a lot less than the thickness of your broken T-washer, lol. The mainshaft has to free to fall down/back tho; I usually stand the trans up in an old wheel with the M/S suspended, and leaning against the bench, in a corner.
 
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AJ/FormS said:
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ; was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

View attachment 1715881083
Click to expand...
Yes, thicker steel plate was there at the bottom.
Yes it seems the contact on all the others was only 2/3's to 3/4
 
AJ/FormS said:
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ; was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

View attachment 1715881083
Click to expand...
20220303_184345.jpg
20220303_184334.jpg
 
AJ/FormS said:
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ; was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

View attachment 1715881083
In the pic below; what is that serrated business just outside the spring clamp? I don't remember any of my hi-drums having that. Is that what cut your planetary?

View attachment 1715881107
Click to expand...
Thing is. I don't want to put new clutches,steels, and bands back in to have the same problem.

Side note. I sent the converter back out to ati today to be gone through. I want to make sure it is OK also.
Ati calculations were over 17% slippage.
There was no bad clutch material in the pan when I replaced the reverse servo. This was after that.
 
AJ/FormS said:
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ; was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

View attachment 1715881083
In the pic below; what is that serrated business just outside the spring clamp? I don't remember any of my hi-drums having that. Is that what cut your planetary? No, I think that is too low. forget it, lol.

View attachment 1715881107

I would take that Sunshell outta there and have a look behind it, that planetary looks a lil high.
Click to expand...

I also have this posted over here
Lost reverse, need help finding it. 727

With the rest of the story
 
The word "index" is going to complicate the procedure in noobs' minds. Does this mean that each plate has numerous indices? NO. they're simply splined together; not ever indexed. Is a converter properly indexed with a pump? A driveshaft yoke properly indexed with an output shaft? NO. An intermediate shaft properly indexed in a th400...SOMETIMES...it only goes together one way; unlike clutch splines.
 
I said my first thought was not supported.
You know it is possible to set that loaded hi-drum over the input, and miss to index the third clutch disc on the splines of the hub. You and I know that is possible.. But you and I know how this doesn't feel right, and so we keep working it until it drops the final plate.
But it has has happened that I have taken apart a trans in that situation, and it was working fine on the remaining two discs, the last one just warped concave . But the remaining discs were just driving on the outside edges. This works fine at Part Throttle, until the discs slip with a lil too much power applied.
From the first post with NO pics, and me not there to see, I originally thought this is what might have happened. So I said;
AJ/FormS said:
As to the clutch; Probably not indexed to the hub-splines properly right from the get-go. Pictures would be very helpful.
Click to expand...
After the pics came up, I saw this was not the case so I said;
AJ/FormS said:
My first thought, not properly indexed, is not evidenced in these pics.
Click to expand...
notice the commas.
I'm sorry if I confused anybody.
 
AJ/FormS said:
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ;
Edit; I mean the first plate to be taken out on disassembly.
was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

View attachment 1715881083
In the pic below; what is that serrated business just outside the spring clamp? I don't remember any of my hi-drums having that. Is that what cut your planetary? No, I think that is too low. forget it, lol.

View attachment 1715881107

I would take that Sunshell outta there and have a look behind it, that planetary looks a lil high. But before you do lift up on the planetary and see how much end-play is on that stack. It better be a lot less than the thickness of your broken T-washer, lol. The mainshaft has to free to fall down/back tho; I usually stand the trans up in an old wheel with the M/S suspended, and leaning against the bench, in a corner.
Click to expand...
Yes, that's what cut the planetary.
 
AJ/FormS said:
Is this burned up friction still flat?
There should be a big fat steel plate about .25 inch thick as the first plate in ;
Edit; I mean the first plate to be taken out on disassembly.
was it there? There is plenty of evidence that the steels were only driving a small percentage of the friction material.; this means something was amiss; they were NOT being properly sandwiched.
My first thought, not properly indexed, is not evidenced in these pics.

View attachment 1715881083
In the pic below; what is that serrated business just outside the spring clamp? I don't remember any of my hi-drums having that. Is that what cut your planetary? No, I think that is too low. forget it, lol.

View attachment 1715881107

I would take that Sunshell outta there and have a look behind it, that planetary looks a lil high. But before you do lift up on the planetary and see how much end-play is on that stack. It better be a lot less than the thickness of your broken T-washer, lol. The mainshaft has to free to fall down/back tho; I usually stand the trans up in an old wheel with the M/S suspended, and leaning against the bench, in a corner.
Click to expand...
20220303_140109.jpg


The diaphragm spring is what was hitting the planetary
 
OK/wait!....
was the broken thrust washer still captive on the pin of the output shaft? and
Did you check the end-play of the input shaft before tear-down?
Cuz I'm getting an idea.
If the washer was out of place,
this would allow the input to move backwards,
which could have allowed the first clutch in, to drop off the splines, (thus no longer indexed). And so then going into Third gear, the clutches would no longer be flat, but with the dropped clutch forcing a twisted engagement, the discs would be now driving on the outer edges. In that state, it wouldn't take much power to make them slip, and burn up/cast off the friction material or just run out of clamping..
With most of the fiber clutch material now gone, the piston would go out as far as it could, but the out of place disc would stop it from clamping
Meanwhile, with the washer out of place, the input moved to the back and the planetary was cut.
I think we got it!
My TFs have all had a tinned-copper over metal Thrust-washer; now I know why. I highly recommend, lol, to not put a fiber washer back in there.
 
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I've only seen one trans that didn't have all the frictions splined to the hub. A guy brought me a TCI that had a three plate direct in it and the bottom plate had the teeth all mashed cuz it was forced together. OEM fibers too. He didn't want to send it back.
 
AJ/FormS said:
OK/wait!....
was the broken thrust washer still captive on the pin of the output shaft? and
Did you check the end-play of the input shaft before tear-down?
Cuz I'm getting an idea.
If the washer was out of place,
this would allow the input to move backwards,
which could have allowed the first clutch in, to drop off the splines, (thus no longer indexed). And so then going into Third gear, the clutches would no longer be flat, but with the dropped clutch forcing a twisted engagement, the discs would be now driving on the outer edges. In that state, it wouldn't take much power to make them slip, and burn up/cast off the friction material or just run out of clamping..
With most of the fiber clutch material now gone, the piston would go out as far as it could, but the out of place disc would stop it from clamping
Meanwhile, with the washer out of place, the input moved to the back and the planetary was cut.
I think we got it!
My TFs have all had a tinned-copper over metal Thrust-washer; now I know why. I highly recommend, lol, to not put a fiber washer back in there.
Click to expand...
I did not check the end Play before I disassembled it. I should have.
I was planning on getting the plated metal thrust washer to replace the broken one.
The broken washer was still on the shaft. Not sure how it stayed there being half of it was missing.
 
Doesn't anybody else recognize moisture damaged frictions when they see them? The moisture affects the glue and the fiber material just falls off in large areas; then it gets chewed up by spinning parts on its way to the pan. I see other frictions that are worn and some that have heat damage, but nothing unusual; that an overhaul wouldn't take care of.
 
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