icetech
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.015 per friction disc isn't it?
Bad fresh 727 noises
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icetech
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soo.. i was thinking. cause my brain obsesses.... what are the symptoms of not enough pressure or too much in a converter... i can't see parts inside rubbing or else everytime you start your car it would have a couple of seconds of no pressure and bad things happening?
icetech
Well-Known Member
Is there any way in the world the input shaft could move forward in second and mess up the converter? I had .080 endplay which is on the high end but still in tolerance.. but i also can't push on it like the clutches would..
Dave6T4
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.015' per disc is a good rule of thumb for front clutch. But rear clutch is 025" for 4 discs. It should tell you that in the instructions.
icetech
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well ****... i probably read the one and figured same for both.. thanks for the tip!
BTW.. since i'm there.. the sprag was working fine.. still has 60 year old springs and rollers... think i should change em?
Dave6T4
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I like them a little less than that, but it is still within factory spec. Sometimes I replace the .086" factory fibre thrust washer with a .100" one from A&A.
Dave6T4
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I have seen rollers with small flats on them. I have a spare set of new rollers and springs here that I may never use. PM me with your address, and you can have them for the cost of CanPost shipping (around $20.00).
Dave6T4
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Maybe that is your problem. There should be two of them; a .062" washer between front and rear drum, and .086" between back of oil pump and front of forward drum.
Dave6T4
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The picture you show is the back of the forward drum, so that should be .062" washer. The .086" washer should be on the front drum support on the rear of the oil pump. If it were missing, your input shaft end drift would really be screwed.
icetech
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Ok.. i found the cause of the noise but not the reason... i was looking through pics i took during disassembly, was going to post them to see if i missed something and i found this..
I was looking at all the machines/wear surfaces yesterday and assumed it was deeper in the trans.. but nope..
So it was self clearancing against tis...
BTW.. when i pulled it apart i saw the rough machining on the face of the stator but checked against my old pump and was the same.. didn't even think bout that beveled area since it should never make contact..
I just went and measured, the pump fiber washer in that pic is .083
so i thought maybe i missed the thurst washer between the drums.. but it's there... and measured .062 dead on..
Soo.. now the question i have is what keeps the input shaft from going forward into the pump like that? I had to have missed a washer or something somewhere.. That pump is a 73+ with the wide bushing and matching drum out of a trans i bought to convert to 24 spline..
I was looking at all the machines/wear surfaces yesterday and assumed it was deeper in the trans.. but nope..
So it was self clearancing against tis...
BTW.. when i pulled it apart i saw the rough machining on the face of the stator but checked against my old pump and was the same.. didn't even think bout that beveled area since it should never make contact..
I just went and measured, the pump fiber washer in that pic is .083
so i thought maybe i missed the thurst washer between the drums.. but it's there... and measured .062 dead on..
Soo.. now the question i have is what keeps the input shaft from going forward into the pump like that? I had to have missed a washer or something somewhere.. That pump is a 73+ with the wide bushing and matching drum out of a trans i bought to convert to 24 spline..
The hole I drill to lube the sprag is .060" thru the case itself. Located on the rear return feed passage under the governer support in line with where the outer race rides. Never had an issue with direct drum bushing wear. My feeling is it doesn't need any hole in the stator support. Lew Mancini was heavily involed with the engineering side of things with years of Torque=flites. One thime there was a question of internal leakage control. He mentioned that that was part of the lube process and was not a concern. Seldom do you see much thrust washer or bushing wear. Except the pump bushing and fiber washers. I have seen outer sprag race wear in the case.
Doug
Doug
B3RE
Active Member
From experience, I'm betting I know what the problem is. Short backstory. My dad had a "trans guy" rebuild the 727 for his '79 D100. The guy said he needed a new pump so he replaced it during the rebuild. The truck had the same issues you are experiencing. Heavy drag in reverse, funny noises, and he also had slippage issues. After I tore it apart, I noticed the same kind of grinding marks you have found. Since the pump was the only thing different from pre-rebuild, I grabbed another used pump from a parts trans, inspected, and installed it. The trans worked perfectly. The problem. The "trans guy" put a pump for a lock up trans in a non-lock up trans. I am betting your 70's pump is for a lock up trans. Find a non-lock up pump and compare the reaction shaft support. Chances are they are different.
icetech
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****, i didn't think of that.. will compare it to the 62 pump as far as length goes.. Do you know if i could need a new input shaft or should just be the pump? I pulled these out of a supposed "Working" trans.. but you know how that is..
icetech
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Thank you btw... hoping you are right.. just glad it wasn't my build that caused it, just the lack of knowing the pump difference
Hoping it didn't hurt the converter..
B3RE
Active Member
As long as the pump and input shaft/front clutch hub are from a non-lock up trans, it should work. I've done this swap in the past with cable shift transmissions to use a modern converter and they've worked well. But, I would try to compare the pump to a later non-lock up version if possible.
icetech
Well-Known Member
will keep a eye out for a trans.. thanks for the nfo.. was hoping to get on the road this summer.. maybe not..
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