727 trans help!

[Fm3 a66]

Ok guys I've got a few questions about a 727 trans in a 1970 cuda.
I thought originally my banging and locking up problem was my differential. see my (help!!! did I wreck my diff? thread for that!) but after swapping the majority of the differential I know that is not the problem! Now my problem is the car is really labouring in gear and almost feels like the brakes are applied! When I do get it moving the car starts banging and the rear wheels start to lock up and then she don't move! I can put it in reverse and it breaks free and will roll back nicely. If I try and go over 5mph it all happens again!  So after some good advice on my previous thread from chryco psycho he's pointed me in the direction of the trans sprag! I can't seem to find any info on the sprag other than them failing during racing and destroying the casing! Does anybody have experience or info on this piece failing or what to look for before I go pull this trans this weekend? Now my other question is while this trans will be out for repair I would like to put another in so I can cruise for the rest of the summer! I have found a 66 Newport with a 383 and 727 in it and I'm wondering will this trans work/fit???
Thanks!

[BFM_Cuda]

I had a charger long ago that had a sprag failure. It would not get any power out of D or 2, but would move normally in L and reverse. Sounds something like your problem, especially the reverse works part...mine never made any banging noises or locked up the output shaft though.

I think you may be at a point of pulling the transmission apart and finding the problem, and it should be obvious. The Monroe A-727 Torgueflite book is a good resource for working on these things.

I looked in that book for your symptoms, and here is what it said:

Dragging or Locking
1 kickdown band adjustment
2 low reverse band adjustment
3 front or rear clutch malfunction
4 broken planetary gears
5 overrunning clutch malfunction *(sprag)*
6 line pressure too low
7 valve body malfunction
8 sticking accumulator, broken accum ring or spring


#1 and #2 are things you can check without removing the transmission from the car, but the rest are internal. My bet is on #5..... good luck.

[Chryco Psycho]

Essentially the 727s are all the same , the housing is different between small & big block , & some internal differences such as different valve bodies , neutral safety switches & converter spline counts & # of clutches inside the drums changed but overall if they are both big blocks it will bolt in & work , it may not have the mount for console shift & will have a different valve body & Neutral switch so reverse lights will not work unless you swap the valve body from yours

[tman]

I say remove, have a trans shop rebuild it, and replace.  Should be a day or two turnaround.  Or tow it to a shop for the job.  Saves you some labor.

[Fm3 a66]

Ok thanks guys! Looks like pulling the trans is this weekends job!

[tman]

Bring your converter too.  If there is iron in the pan, its in the converter too.  That will probably need to be replaced.  Flush transmission lines to radiator to clean out metal.   Good time to have a shift kit installed if you like.
 
Here is a 19 part video of rebuilding a 727.  Part 11 deals with installing sprag.  Thing is, you don't know if the sprag is the exact issue, although it could be.

https://www.youtube.com/watch?v=xzJhCBZ1wMY&list=PLA9698F0D2698CD77

[RzeroB]

Sounds pretty bad ... you don't really want to mess with that can of worms do you? Just get Pops into a new Challenger and dump this old nag. I can still be there this Saturday with the flatbed to take it off your hands.

I don't think I would pull the trans just yet. It was working fine before you put into storage right? Now, after a couple of years in storage it started acting up right? Trans sprags just don't go bad from sitting in storage. It sounds more probable that something in the valve body is gummed up. Perhaps a good flush and band adjustment is all it needs? Problem is finding a competent trans shop that has experience with those old 727's. Now a days everything is "remove and replace" and trans shops just want to remove and replace the whole thing. A good trans shop would be able to flush it, adjust the bands and check and adjust the line pressure for you. It just seems more probable that if it was working before it went into storage that it would be something related to being inactive for a couple of years (something gummed up) vs it having a sprag, planetary, or some other "hard" part failing while it was in storage.  

[734406pk]

I say remove, have a trans shop rebuild it, and replace.  Should be a day or two turnaround.  Or tow it to a shop for the job.  Saves you some labor.

keep your existing transmission and get it rebuilt. 727's are very simple and should only take a day or two to finish. Just be sure to flush the cooler and lines!

[BIGSHCLUNK]

  Just be sure to flush the cooler and lines!

I can not emphasize this enough!!!! I've seen so may tranny's screwed up over the years because people don't do this one simple step.

[Fm3 a66]

Ok guys I had some time to work on the car this week and I managed to get myself a big 1970 shop manual! So before I just tear this trans out I figured I would try and learn and diagnose as much as possible! I will be getting myself a pressure guage and going through the process of checking all trans pressures and trying to adjust as needed! I did however remove the tailshaft housing to inspect the bushing and bearing and discovered the bushing is shot! The bearing does have alittle wobble to it so I will replace those while I'm waiting on my pressure guage to come in. I did however notice the output shaft can be moved in and out about .250! With the tail housing off! Is that cause for alarm? Also my driveshaft which is correct length for the car stick out about 2" is that normal or is that killing my bushing? (pic attached). And my last question is can anyone decode this trans for me? I've looked online and can't find much info! Here are the numbers off the drivers side. (Pic attached)
K4058395 7047 0809