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  #1  
Old 07-22-2002, 04:33 AM
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5th_Ave_Sleeper 5th_Ave_Sleeper is offline
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cry2 727 wont shift/ locks down(really long post)

The 5th Ave runs great! it just wont drive down the road.
The patient:
1986 Chrysler 5th Ave. rebuilt 360, very strong motor! runs great so far. Tranny is a 77' TF 727 that I rebuilt myself with a transtar kit from Northern Auto Parts. Also I installed a B&M shift improver kit in the valve body. It has a MPP 2500 stall non-lockup conv. 9.25"rear with 3.55 gears.

The symptom:
trans will go into R and back up all day long. It will go int D, 2, 1 no prob. when driving foward the trans will "neutral out" between 1st and 2nd, and will never make it to 3rd.
When it gets into 2nd it locks down like im pushing on the brakes, so i mash the loud pedal more then it starts jerking and locking down even more till i let off the gas put it in N and start all over again.
All this happens under 20MPH

What Ive done:
I immediatly got it back to the garage and dropped the pan found a bunch of crud in it. removed valve body and found the 1" by 1.5" steel "link" that goes between the low/reverse servo arm and band had fallen out. I put back in, re-adjusted the band so it would not fall out again. Completely disassembled valve body, cleaned it and everything that came out of it VERY, VERY well, re-assembled exactly, re-installed with new filter and fluid. Tried it out on the street and STILL have the same Problem!


My theories:
1> the damage to the low/ reverse drum was minor. my only concern is that the arm is not in contact with the servo. it hangs down about an inch. is the "nipple" on the servo arm supposed to be in constant contact with the servo piston? Can I make a longer link to compenseate for this?
2> its that POS shift kit. I have been searching the archives for trans problems and have run across some (alot) of negative feedback about B&M's shift improver kit. Is it easy to switch from the b&m to a transgo shift kit? or did I throw away pcs that I need?
3>Throttle valve mis adjusted. I will try adjusting this first thing when I get home this morning.
4> I am going to rule out all the rotating internals because I did the 30 psi air pressure checks when the V body was off, everything operated corectly. There is the possibillity of the overrunning clutch I guess.
Boy, thats a long one! I know trans problems are hard to diagnose, but any help would be great! I really want to drive this car to the Mopar Nationals!
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  #2  
Old 07-22-2002, 09:11 AM
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1972roadrunner 1972roadrunner is offline
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sounds like you've pretty much got it covered...only thing i could think of is the kick-down linkage....

i need to learn a LOT about tranny's....i don't deal w/em, i just take it to "Leeper's Transmissions" and thats it... the guy does a great job w/727's....i haven't had a problem with mine yet...

BTW: Leeper also has a dart, charger, swinger, and a couple of other mopars... great guy!! they are all running too!
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  #3  
Old 07-22-2002, 10:28 AM
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Unhappy help please

c-mon fella's I know you experts are chompin at the bit to help me out here
5th
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  #4  
Old 07-22-2002, 01:20 PM
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The arm definitely should be in contact with the servo piston at all times. Correctly adjusted you should be able to pull away about a half inch and the spring action of the band should snap it back in contact. Possible problems here, both of which have happened to me at one time or another.

1. 1 x 1.5 steel link inserted incorrectly. The 1.5 side should be between the band and the lever arm. If installed the other way, you will have problems (likely since it fell out).
2. Incorrect band. Once got a GM band in a Mopar kit by accident. It fits and looks almost the same, but is too large and won't sufficiently stop the drum.

Assuming the kickdown linkage to be adjusted correctly, other easy things that ought to be checked and recorded before pulling your hair out.

1. Are you sure the torque converter is of the non-lockup variety? Stock converter in an 86 5th would most likely be a lockup which just won't work with a 77 non-lockup TF.

2. Line pressure check at all three (main,rev,gov) test ports. This can tell you a ton about what's going on and only takes about an hour. If you can swing it, try to monitor it while that bad gear change takes place.

3. Double check the adjustment on both bands. Easy to get it wrong.

This is just a start.
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Old 07-22-2002, 01:41 PM
Tarrbabe Tarrbabe is offline
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Question 727 Locking down

I'm no expert, but have built my tq's for years. I had my 727 do pretty much the same thing. It seemed ok until it hit drive and locked the rear tires. Upon teardown I found the facing distroyed and band stuck to the drum. I'd check the band and drum surface. I'm just glad I wasn't driving like I often do. I was only doing abut 45 when it locked down.
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Old 07-22-2002, 05:22 PM
John Kunkel John Kunkel is offline
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I'm confused, you stated that the trans "will go into R and back up all day long" but you found the rear band link in the pan? Without the rear band it won't go into reverse.

You stated that you "readjusted" the rear band but the lever hangs down an inch? Huh? If the lever hangs down an inch, it's not adjusted.

Throttle pressure linkage adjustment might explain the delayed 1-2 upshift but it can't cause the bind up you describe. The only possible cause of bind up is the trans trying to be in two gears at once.

Are you sure the shift improver kit is proper for the trans? What's the B&M part number? To be safe, remove the kit and return the valve body to its original configuration.
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  #7  
Old 07-22-2002, 06:40 PM
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Default some clarification

After I re-installed the low/rev link, R works fine. So that tells me that band and clutch drum works fine.
The low/rev band adjustment is bottomed out. I cannot adjust it any further yet the arm still hangs well below the servo. should I get/make a longer link? to compensate?
I agree with you, Mr. Kunkel the trans is trying to be in two gears at the same time. Unfortunatley the parts that were removed from the Vbody are long gone.
I still say its all in the valve body (except for the L/R band thing). How much is a 727 valve body? can I get one at a trans shop cheap?
I am doing research for a while before I go back into the garage, I am so disgusted with this car. I have been working on it here and there for about a year and a half just to have this happen Oh well one step at a time.
5th
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Old 07-22-2002, 11:39 PM
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Unhappy wheres the tranny guys!

Transfixleo, are you out there?
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  #9  
Old 07-23-2002, 01:37 AM
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:shock: Bad news?

So, I had a conversation with a guy that used to rebuild trannies. and he told me that the rear band (low/rev) is supposed to have a lining on it I know for a fact that mine does not. That would explain why I am all out of adjustment on that band DUH!
Metal to metal is not a good thing in auto trannies now is it.
Oh well, what can you expect from my firs ever trans rebuild. I still say somthing else is wrong in the Vbody!
What are your thoughts?
5th
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  #10  
Old 07-23-2002, 10:19 AM
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5th Ave,
Something is definitely wrong with the rear band beyond just not having a lining. Either the link plate is installed in the wrong orientation, or you straight up have the wrong band. It can happen. Jack up the rear wheels and put it in N, then pull the rear servo arm down as far as you can. With the other hand, physically try to rotate the rear drum. If you can rotate it even with the arm pulled all the way down, then this is the cause of your problem. Don't throw away your valve body just yet.
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  #11  
Old 07-23-2002, 03:53 PM
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Thumbs up one thing at a time

Gonna pull the trans and replace the rear band and drum. trans shop said that there is definatly supposed to be a lining on the rear band just like the front one. well that metal to metal contact has scarred up the drum as well, and I'm sure that would shred a new band, so...
Oh, this trans fluid is starting to get expensive, think it would be ok if i strained it through a clean T-shirt? its only got 1/4 mile on it. I've gone through 18 qts of fluid so far tryin to figure this out. I'm runnin out of 5 gal buckets to put it in
5th
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  #12  
Old 07-23-2002, 04:46 PM
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18 qts.? My record for a single tranny is over 30 (9 separate fills).!

Good luck.
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  #13  
Old 07-23-2002, 05:27 PM
John Kunkel John Kunkel is offline
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The absence of lining on the rear band is probably the result of it being worn off by the band applying at the wrong time. This ties in with your binding up problem.
There is a test port in the case at the rear servo. Hooking a gauge to that test port will show if the rear band is applied while the trans is trying to upshift. If it is, that's the source of the binding.
About the only thing that will cause this is a malfunctioning valve body or a warped case.
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  #14  
Old 07-29-2002, 12:38 AM
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Viola!

It was a bad valve body after all! I Got a VB out of a 904 that was in an AMC Mattadoor! It works great! I will let the tranny shop install the shift kit in this one. I aint messin with it
Thanks for all your input and help. I would never have finished this car if it werent for the members on this board. So cheers to all!
5th
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