727 - Let me describe my symptoms...ugh

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MrJLR

Built, not bought
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Rebulit my 727 a couple years ago....been working GREAT....

Last week i was out driving and it felt like it tried to grab 2 and 3 at the same time....came to a stop, started back off in first and all was fine again....odd...

This morning i fired it up and reverse took a long time to engage....never done that before.....
I get around the corner and it wont shift out of first.....then, it like locks up the rear wheels....I threw it into netural and stopped.
Tried again - same crap.....
I was just around the corner, so I drove it in reverse back home. Pulled it back in the garage in first - it drives forward in first as love as the RPMs are low......

So, the obvious question is - WTF?!!!!!! LOL

Jeff
 
You need an 1/8" npt x hose adapter, about 4' of high pressure hose, and a 0-300 psi gauge with a large face, like 3 or 4". Also a good book, factory service manual, etc. Pressure tests are easy, port taps are all over the trans.
 
Your reverse band is grabbing it sounds like. Reverse and 1st use that band I believe. It "locked" up on you when it tried to shift to 2nd and the reverse band was still engaged.

I had my 727 rebuilt last year by a "professional" trans builder that specializes in mopar. That POS rebuild made it about 5 miles before it lost 1st gear and slipped through 2nd. Reverse was also gone.

He re-rebuilt it as a warranty. He blamed my new PTC converter, new pre bent cooler lines, or my new HD cooler as the issue. The 2nd build made it a few more miles (about 10) but it locked up on me at ~35 MPH on a backroad and actually locked the rear wheels up! I spun off into the grass and had to get towed home.

I pulled it apart and the reverse band was locked on and had destroyed the drum. The servo was cracked and bent. I think he messed the valvebody up on the 2nd rebuild and caused most of that.
 
Your reverse band is grabbing it sounds like. Reverse and 1st use that band I believe. It "locked" up on you when it tried to shift to 2nd and the reverse band was still engaged.

I had my 727 rebuilt last year by a "professional" trans builder that specializes in mopar. That POS rebuild made it about 5 miles before it lost 1st gear and slipped through 2nd. Reverse was also gone.

He re-rebuilt it as a warranty. He blamed my new PTC converter, new pre bent cooler lines, or my new HD cooler as the issue. The 2nd build made it a few more miles (about 10) but it locked up on me at ~35 MPH on a backroad and actually locked the rear wheels up! I spun off into the grass and had to get towed home.

I pulled it apart and the reverse band was locked on and had destroyed the drum. The servo was cracked and bent. I think he messed the valvebody up on the 2nd rebuild and caused most of that.

Should i slightly back off the reverse band?
Im hoping i can solve this without pulling the trans out.....

Jeff
 
Should i slightly back off the reverse band?
Im hoping i can solve this without pulling the trans out.....

Jeff


NO! If the band adjustment is TOO loose it can allow the servo to over travel and bind. That'll cause The band to stay engaged.

I would pull the pan, inspect it all, adjust the band properly and see of that all works. Pressure tests aren't a bad idea either but a band adjustment and visual inspection is where I would start.
 
that sucks Jeff I hope it's an easy fix . your rebuild thread was one of my favorites .
 
I had my 727 rebuilt last year by a "professional" trans builder that specializes in mopar. That POS rebuild made it about 5 miles before it lost 1st gear and slipped through 2nd. Reverse was also gone.

He re-rebuilt it as a warranty. He blamed my new PTC converter, new pre bent cooler lines, or my new HD cooler as the issue. The 2nd build made it a few more miles (about 10) but it locked up on me at ~35 MPH on a backroad and actually locked the rear wheels up! I spun off into the grass and had to get towed home.

Don't mean to highjack a thread, but I gotta know...... can we all spot that mechanic easily because he's the one with a tire iron wrapped around his neck??!!
 
Maybe 10,000 miles...

Jeff
My first instinct was to just keep my mouth shut and let you find out for yourself instead of being the devils advocate, but it sounds like something is coming apart and jamming shift valves.
Possibly a planetary set or some other metal particles producing failure.
Could also be a sealing ring broken allowing fluid where it doesn't belong yet and binding it up, or one valve making the shift and another not letting go.

Very first thing would be to pull the pan and have a look at the contents.
 
Jeff, sorry to hear that. I can’t believe it’s been two years and 10,000 miles already. I used you’re rebuild thread and you’re experience to help build mine which I just took for the first ride two days ago. Shifted good, but the shifts where soft. My guess the 3k stall is softening the shift Kit a bit. I wish you the best of luck with yours.
 
Start simple, work towards complex. Check the bands, drop pan, inspect and go from there. Best of luck!
 
Rear servo cocked over and locked rear band on, probably has band wasted when it bound up in forward . Pull it out only way to fix it,
Lon
 
Lots of good answers.
If the shift quadrant is properly indexed so that the manual valve is properly detented, then
I think it's past oil pressure testing, and for sure the pan should come down.
Locked in reverse has only one cause, the band is applied. Could be mechanical failure. Could be hydraulic. At least the high-drum is working,lol.
But I'm confused about the excessive overlap on the 2-3 shift, which you say came first, and has nothing to do with the reverse situation. So... an air pressure test might help,
but as for myself; I'd be taking it down for a full tear-down. In about an hour to 90 minutes, it will be on the bench with it's guts spewn all over the place, and a full diagnoses made.
 
Don't mean to highjack a thread, but I gotta know...... can we all spot that mechanic easily because he's the one with a tire iron wrapped around his neck??!!


I didn't even bother to go see him after the 2nd screw up. I'm far from a trans builder, but I can build a trans better than that. And I did! It shifts great now. My friend night still have some dealings with him and I didn't want to burn that bridge.

My buddy bought some B1 heads, rockers, etc from him that ended up needing a BUNCH of work to fix. Rockers were beat up, heads weren't flat, valve guides too loose and some too tight, the springs weren't a matching set, etc... He also bought a nice mopar bellhousing Reid case "built" powerglide. We will see how well that works (or doesnt) hopefully this spring.
 
Your reverse band is grabbing it sounds like. Reverse and 1st use that band I believe. It "locked" up on you when it tried to shift to 2nd and the reverse band was still engaged.

I had my 727 rebuilt last year by a "professional" trans builder that specializes in mopar. That POS rebuild made it about 5 miles before it lost 1st gear and slipped through 2nd. Reverse was also gone.

He re-rebuilt it as a warranty. He blamed my new PTC converter, new pre bent cooler lines, or my new HD cooler as the issue. The 2nd build made it a few more miles (about 10) but it locked up on me at ~35 MPH on a backroad and actually locked the rear wheels up! I spun off into the grass and had to get towed home.

I pulled it apart and the reverse band was locked on and had destroyed the drum. The servo was cracked and bent. I think he messed the valvebody up on the 2nd rebuild and caused most of that.

Scott barker @ Barker auto. in pryor , or Wayne Smothers in Oolagah =torqueflite.
 
Scott barker @ Barker auto. in pryor , or Wayne Smothers in Oolagah =torqueflite.

I've heard of smothers. I've even looked at a couple of "Smothers Tuned" cars. He does great work.

The shop that did mine is B&R transmission and chassis fab in Tahleqhah.
 
Jeff wake up!!!! Get out in that garage and take that pan off. I remember you had trouble originally with that rear servo going crooked then you replaced it with another stocker. I'm hoping that's all it is, if so upgrade to one of Randy's or Copes billet servos. Cheers
 
I've heard of smothers. I've even looked at a couple of "Smothers Tuned" cars. He does great work.

The shop that did mine is B&R transmission and chassis fab in Tahleqhah.

Yeah , Wayne is a guru , a little nutso too ! LOL , good guy .

I posted this already , but I saw you on an old roadkill yesterday .
 
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