727 issue - Moves forward in all gears

[mopar 3 B]

A stuck rear clutch could make it move in all forward gears. If the high clutch and KD band operate normally the trans would also have 2nd and 3rd gear.
Doug

But assuming the bands are adjusted correctly and valve body is ok there should be no bands or clucth packs applied in neutral. Both clutch packs would have to be applied to make it move in neutral. Big question why is the converter also locked? At idle should not be turning enough rpm to lock it. My suggestion would be to park it before someone or something gets hurt.

 

[mopar 3 B]

Yes, but the builder honored it, I paid R&R,
and he worked all weekend on it.

He's very well respected, to say the least.

Well respected. But he will never work on my stuff this is a day job even in my driveway.

 

[Marksman]

We're going to pull the transmission Friday and swap the guts from his small block trans into the BB case for simplicity sake, since we don't have a kit for it. I've been into 727's multiple times and done this swap before so it shouldn't be much of an issue.

 

[Darthomas]

Well respected. But he will never work on my stuff this is a day job even in my driveway.

More than well respected, practically famous, and his transmissions are in many of the fastest Mopars of many members here.
I have never had the tools, space, or clean area to do such a job.
I have installed transmissions that he built, built and installed engines, and lots of other major jobs.
It was deep cold winter , and it was my daily driver, he busted *** to get me back on the road.

 

[Marksman]

Here's another problem. Drove the Charger for the 2nd time today (first time was up the street and back slowly) and couldn't get the thing to shift from 2nd to 3rd. I tried up to 60 MPH and I figured if it were going to shift, it would have by then. I adjusted the kickdown linkage which didn't help any. I don't think the linkage I have on the car is correct. It has the stock AVS and the kickdown lever isn't level with the throttle rod. It slopes downward from the carb to the pivot point.

I have the style linkage on it that you adjust from the bottom of the car.

Both of the Barracuda's and the sport fury have the type that adjusts from the top. Every other car on the place is either a 4 speed or doesn't have an engine. I'm going to borrow the linkage off of my d200 and see if it works since it's a 440, and the others are either small blocks or 383's.

Next I will assume the valve body or a damaged servo. It shifts nice and crisp from 1-2 at about 18 mph.

Any thoughts?

Thanks!

 

[mopar 3 B]

We're going to pull the transmission Friday and swap the guts from his small block trans into the BB case for simplicity sake, since we don't have a kit for it. I've been into 727's multiple times and done this swap before so it shouldn't be much of an issue.

Not all years parts and cases are compatible so be careful.

 

[383man]

Time to drop the pan and see what is going on. One stuck clutch pack will not keep it going forwards in all gears nor will a stuck overrunning clutch.
With the valve body removed everything can be pressure checked. Time to get the FSM out and go to work.

 

[Darthomas]

Did you try getting it up to 45, put it in Neutral, let back some on the gas, and then putting it back in drive?
I'd like to know if it drops into 3rd then.

Are line pressures set to spec, or high, or low?

 

[383man]

Time to drop the pan and see what is going on. One stuck clutch pack will not keep it going forwards in all gears nor will a stuck overrunning clutch.
With the valve body removed everything can be pressure checked. Time to get the FSM out and go to work.

Yes it will. The overrunning clutch dont need to be stuck as it works at all times in forward gears. All you need to move forward is the rear clutch pack applied. The overrunning clutch will already work as first gear is just the rear clutch and the overrunning clutch. A welded together or stuck rear clutch pack will make the car want to go forward in all gears. And since he said it lurches in park that tells me the shifter workes since its in park and the parking pawl is applied and the rear clutches are most likely stuck together applying first gear trying to make it move all the time. Just stuck on band by itself will not make the car move forward as it needs a clutch pack applied also as no band by itself applies a gear. Ron

 

[383man]

But assuming the bands are adjusted correctly and valve body is ok there should be no bands or clucth packs applied in neutral. Both clutch packs would have to be applied to make it move in neutral. Big question why is the converter also locked? At idle should not be turning enough rpm to lock it. My suggestion would be to park it before someone or something gets hurt.

No it will move forward with just the rear clutch pack on. First gear is just the rear clutch and the mechanical working overrunning clutch with works all the time going forward at lower speeds. Ron

 

[747mopar]

Simply swapping the inners could be a catastrophe, not only are there differences but just like anything else there's clearances that need to be addressed. As Mopar 3 B has said testing the circuits with an air nozzle (preferably a rubber tipped one) while the valve body is removed will at least give you an idea if they're shifting. I wouldn't drive it like that but that's just me.

 

[mopar 3 B]

Decided it was time to separate the BS from the facts and did some research. This refreshed my memory and should aid you in disassembly as to what to look for.
For those whom wish dispute the validity of this info this information was extracted form from Chrysler Corp. Service Training Fundamentals of Automatic Transmissions and Transaxles TM-608-A.

 

[mopar 3 B]

No it will move forward with just the rear clutch pack on. First gear is just the rear clutch and the mechanical working overrunning clutch with works all the time going forward at lower speeds. Ron

Ron that is the case in D and D2 and is why one should never take off under heavy load in any gear but D1 where the overrunning clutch is not applied. If you have ever destroyed one you will definitely remember this.

 

[MOPOWER871]

I understand you like to work on your stuff but your under the gun ,time is the major factor. bite the bullet get a new unit and go have fun.when you have time then go threw it .good luck

 

[383man]

Ron that is the case in D and D2 and is why one should never take off under heavy load in any gear but D1 where the overrunning clutch is not applied. If you have ever destroyed one you will definitely remember this.

I did not say anything about that as I was just stating that the 727 trans will move forward with only one clutch pack applied as you said you need two clutch packs applied to move forward. I was only stating that only one clutch pack needs to be applied for it to move forward since it has the mechanical overrunning clutch. Dont matter where the shifter is if the rear clutches get welded together (which I have seen many times) the car will want to move forward. Thats basically all I was saying and the fact that a band stuck on by itself wont make the car move. Actually in any forward gear even D1 the overrunning clutch is still applied but the low/reverse band will override it. Now if you put it in low (D1) and the low/reverse band is broke the car will still move and the only way you would know the low/reverse band is not working is that you would have no eng braking. And also no reverse. Ron

 

[383man]

c

Decided it was time to separate the BS from the facts and did some research. This refreshed my memory and should aid you in disassembly as to what to look for.
For those whom wish dispute the validity of this info this information was extracted form from Chrysler Corp. Service Training Fundamentals of Automatic Transmissions and Transaxles TM-608-A.

View attachment 342544

I did not give any BS as I know the 727 trans very well and all I said it correct. I worked on them for 24 years at a Dodge dealer. The bottom line is the poster asked why his car moves forward in any gear. And once he said it tries to move in park also any good trans person would know the rear clutches are stuck and the trans has to come out. No band will cause his problem. Then you can air test all the clutches and servo pistons when you rebuild it as I always do. Ron

 

[Marksman]

After swapping and adjusting the linkage, it shifts into 3rd fine. Problem solved.

 

[dvw]

After swapping and adjusting the linkage, it shifts into 3rd fine. Problem solved.

Did I miss something, or was the issue linkage the entire time? If so how did it crank with the neutral safety switch not grounded in drive, no switch? A note to Mopar 3B thinking that it wouldn't move forward with a damged/siezed rear clutch. When you have been doing Torque Flights as long as Ron and I and have, you get to see many different strange and damaged items. When you've seen a trans with a siezed rear clutch failure come back and comment.
Doug

 

[Marksman]

Sorry for the confusion. The shifting into third problem was on my Charger, got it resolved with kickdown linkage.

Pulled the trans out and apart on the Satellite to find,as suspected, the clutches were welded solid. Everything was discolored and had obviously been pretty hot. Swapped the guts, got it back in around 3am Saturday and it backed itself off the ramps, so that problem is now solved as well.

 

[Darthomas]

If there's any forward pull in Park, have a damngood look at that gear select valve spool, or never warm up the car in fast idle unattended with the valve body that was there when that happened.
Or put it in neutral and use the parking brake.