727 trans rebuild

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mean318

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I am in the middle of rebuilding a big block 727 trans and I have a few questions. First; I have all the clutches and bands back in the case and there is very little end play on the input shaft only if I pull really hard on the end shaft does it come out about .050" I am guessing. I put a .098 thrust spacer between the pump and front clutch. Both shafts move without binding. Second; How much play should be in the clutch packs after they are assembled?

Thanks for the help,
Cory
 
Cory .050 is alot of end play but I see you say your guessing so you need to get a dial indicator and check it to make sure what it is and not guess. It must be correct. I usually set them at .015-.020.


The clutch pack clearance varies according to how many friction plated are in the carrier. .010-.012 per friction is the norm so if your carrier has 4 frictions you should have .040-.048. BTW: Shouldn't you have checked that before you installed them.
 
Yeah I know I should have checked it before I installed them but its no big deal pulling the stuff back out. Thanks for the reply and your help
 
My next question is, is how easy should the input shaft move in and out? Also is the .010-012 rule the same for both clutch packs?
 
It should move easily until you reach the limit of the freeplay. There should be no binding.

Yes the same figures apply to both clutch packs.
 
Fishy68, I dont doubt you i only ank this because i just rebuilt by first 727 and was going to bolt it in on sunday. i gat a book from amazon on 727's and the specs for it said end play .039-.089 cant rember clutch pack specs but they were different between the two, 4 disks each i belive one was .025 min.
and the other was .065. also what would proper band adjustment be. and is there a difference between flat spring specs and wave spring specs. sorry for all this but better to find out now then after its in.
 
Well, the clutch packs are good to go, but I am having a big problem with my end-play specs. When I look at the book it says to have a plastic thrust washer in between the pump and front clutch pack, My thinking is that it should be in between the input shaft and the front clutch pack. The endplay is WAY too much like .150". I think where I really messed up is that I did not check the end-play before I took it apart. Any ideas?
 
dazedduster said:
Fishy68, I dont doubt you i only ank this because i just rebuilt by first 727 and was going to bolt it in on sunday. i gat a book from amazon on 727's and the specs for it said end play .039-.089 cant rember clutch pack specs but they were different between the two, 4 disks each i belive one was .025 min.
and the other was .065. also what would proper band adjustment be. and is there a difference between flat spring specs and wave spring specs. sorry for all this but better to find out now then after its in.
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No problem. Those sound like factory specs. I build every trans. to tight tolerances to make them last longer. With less slop things don't go bump in the night so hard and last alot longer. The specs in the book on the clutch packs were probably different because the rear clutch is not a shifting clutch pack. It's engaged in all 3 forward gears so it can be much tighter. The front clutch is the high gear clutch so it's a shifting clutch pack so it needs to be looser.

There's really no difference between flat retainer specs and wave retainer specs. You set them the same. I will say that if I find a wave retainer in the forward clutch I take it out and put in a flat one.

The band adjustment depends on which trans you have, what year, and how it's set up as in what front band ratio.
 
Isn't there a video on rebuilding 727's available? That sure would be a great way for a novice like me to gain some understanding.
 
mean318 said:
Any ideas on my problem?
Click to expand...

Sorry man I forgot to answer you back. There is a thrust washer between the 2 clutch packs but it's a fixed thickness of .063 The one between the pump and front clutch is the only one you want to change thickness on. .150 is a tremendous amount which makes me think you left out either the small metal thrust washer between the input and output shafts or the .063 fiber thrust washer between the clutch packs. Double check to see if they're in their.
 
wedgie said:
Isn't there a video on rebuilding 727's available? That sure would be a great way for a novice like me to gain some understanding.
Click to expand...

Their might be a video but I haven't seen one. There is a fantastic book written by Carl Munroe called "Rebuilding the 727 Torqueflite" It is very well written and easy to read and covers all aspects of rebuilding from stock to all out racing. Has lots of good pics too. You can get it off of Amazon.com or E-bay for less than $20
 
fishy68 said:
Sorry man I forgot to answer you back. There is a thrust washer between the 2 clutch packs but it's a fixed thickness of .063 The one between the pump and front clutch is the only one you want to change thickness on. .150 is a tremendous amount which makes me think you left out either the small metal thrust washer between the input and output shafts or the .063 fiber thrust washer between the clutch packs. Double check to see if they're in their.
Click to expand...

The one between the shafts is there, and I tried with and without in between the the clutch packs. I'll have a look through again to see if I haven't forgotten anything. I should be done with it today. Thanks for all your help Fishy
 
mean318 said:
The one between the shafts is there, and I tried with and without in between the the clutch packs. I'll have a look through again to see if I haven't forgotten anything. I should be done with it today. Thanks for all your help Fishy
Click to expand...

Double check stuff in the back gear assy. too. Anything missing can cause slop like this.

I got faith in ya man. You'll find it.
 
Hey Fishy when I check the end play do I need to have the kickdown adjusted to specs? It seems that pulling on the input shaft wants to pull the rear clutch assy. out of the lugs of the drive drum is this normal? When I snug down the kickdown band I get the correct endplay at the input shaft with a .064 selective washer in between the front pump and front clutch.
 
Sorry need to correct something, when I pull on the input shaft without snugging down the kickdown it wants to pull the front clutch out of the drive lugs.
 
You need the kickdown band loose. It doesn't have to be adjusted correctly, just loose enough to allow the clutch packs to move freely.

You didn't change any hard parts did you? Like the front pump or clutch drums. I haven't seen any with that much play unless parts were mismatched. It's either that or something is missing like a thrust washer in the gear train. I can't think of any reason it would have that much slop. The thickest thrust washer I have ever had to use was .108 and that got it tight.
 
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