727 help please

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timopar

timopar

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can anyone tell me if this looks right? My problem is, after only a few miles on my fresh tranz reverse stopped working.
So I read over HP books 727 tranz handbook, witch is what I used to guide me thru the build. I also read over my 1965 Chrysler service manual and they both pointed to the rev/low band adjustment.
so I pulled the pan, torqued it to 72"lb, backed it out 2 turns, put it all back together and yeahah! reverse works again.
I went for a little drive around the block and reverse was slipping when I got back, same again after less than 10 miles of driving reverse stopped working. Has anyone had this problem before?
I built the tranz with a kit from mancini, the kit did not have a low/rev band, so I just put the old one back in. was that a mistake?
The valve body is a factory unit modified, reverse patern, manual shift and Im only running the factory spring in the accumulator. thanks in advance fellas, any help would be great.
 
check that rear servo...........


looks like there is way too much clearance on the arm......

are you sure the band strut is on correctly????
 
did you hone the bore with a ball hone? install a new lip seal. remove that heavy a$$ spring and shim the servo with a washer and toss the accumlator spring and install a blocker rod.i have a band and drum if you need one.
 
thanks guys, all seals and gaskets in the box were new when I put it back together and on checking back over it the servo piston/seals and bore finish seam fine to the naked eye. tho I didnt hone the bore.
I found very fine iron fillings in the bottom of the tranz pan and I can't see any friction material on the band, so my guess is Iv eaten thru what friction material was left on the second hand band. dos that sound feasible?
 
That band adjustment looks way to loose to me. There is no reason to have to modify things to make reverse work properly. None of that was done from the factory and reverse worked fine and still works fine on every stock rebuild I do. Those are performance modifications except for honing the bore and that should be done only if needed as you take material out when you hone it and that makes the piston fit sloppier and more prone to flipping or cocking in the bore and getting stuck. And replacing the accumulator spring with a blocker rod has absolutely nothing to do with reverse. That's to make it shift firmer into 2nd gear.

It is possible that all the friction material is used up on the rear band. How did it look when you put it together? Although I prefer to replace all parts I have re-used the rear band before if it was in good shape. You just have to inspect it carefully and make sure the friction material is good and not heat cracked/stressed.
 
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