727 - Won’t go into Park or Gear

[Chadiator]

Hi all! I’m just wrapping up my 440 rebuild, and it’s back in the car and humming along!

During the process, I pulled the perfectly working 727 to swap a few seals. Well, it was perfectly working until now…

I changed both the input and output shaft seals, as well as the obvious pan gasket, filter and fluid. The last thing I changed was the shift shaft seal, which I did from above without removing the shaft.

Now back in the car, fluid is full and pumping, but I don’t get any response from any gear with the car running (it’s on the hoist so the wheels have no resistance). We even tried finding park, but every “notch” we shift it through, we can still rotate the driveshaft by hand. We removed the linkage and did the shifts by hand on the transmission itself to eliminate any issues between the column shifter and the trans. You can feel it “click” through the notches, but at either end of its range, it feels like it doesn’t want to go all the way (goes halfway between a click).

Something must have gone wrong when I changed the shift shaft seal, but I’m not sure what. I REALLY don’t want to drain and refill the transmission again, so I’m hoping there’s something really silly I’ve missed.

My assumption is something has disconnected internally on the bottom side of the shaft and that I’ll probably have to pull the valve body to assess.

Has anyone run into similar? The other threads I’ve read seem to have some elements of my problem (ie will go into gear, but not park), but not all.

 

[pnora]

Sounds like the front pump has the two tangs busted off.

 

[Don Frelier]

Sounds like the front pump has the two tangs busted off.

In other words the torque converter was not seated fully on the input shaft when you reassembled it.
Did the bell housing line right up with the back of the block once the dowel pins were aligned?
Or did you have to pull it up using the bolts?
If the latter then it's not a good sign.

 

[turbine68rt]

Was the E clip that retains the kickdown rod removed at any point? I would drop the pan and confirm that the arm near the NSS wiper (if '69-up) is properly engaging the manual valve. When you say the fluid is full and pumping, how was the pumping confirmed? Either way, the park rod engaging with the parking gear is strictly mechanical, so those components will need to be inspected for any damage.

 

[Chadiator]

Thanks all.

Re: fluid and pumping. It was well over full on the stick before starting, and dry once the car was running. I worked it up to reading at a good level when running. Was hoping low fluid caused the issue but doesn’t seem to be the case.

Re: torque converter. I triple checked that it seated correctly and engaged on the input shaft. I also did not have to use the bolts to bring it into alignment. Everything went together fairly easy, all things considered. I can’t even find “park” currently, so it seems like it’s not just a power transfer issue.

Re: kick down shaft. The e-clip did come off, yes. Sounds like you’re onto something there. I think the shaft dropped down a bit when the clip was off, and I had to pull it back up and “out” of the trans to get the clip to seat back in. I’m thinking something disconnected internally when that happened. Does that sound logical?

 

[Chadiator]

I just found a thread that sounds JUST like my issue. When I let that kickdown shaft drop in half an inch, I bet things misaligned internally.

Sounds like the valve body will be coming out tonight! Ha!

Great photos in this thread, too:

a bit of help please with 727 transmission

 

[Chadiator]

Was the E clip that retains the kickdown rod removed at any point? I would drop the pan and confirm that the arm near the NSS wiper (if '69-up) is properly engaging the manual valve. When you say the fluid is full and pumping, how was the pumping confirmed? Either way, the park rod engaging with the parking gear is strictly mechanical, so those components will need to be inspected for any damage.

Looks like I found the issue. This little lever needs to get back in between this valve rod (I don’t know what else to call it). Here’s photos of what it should look like vs what mine looks like.

Does anyone have a suggestion on how to get it back in there while touching as little as possible? (To not create another issue through disassembly)

 

[turbine68rt]

That's what I was referring to regarding confirming if the arm is properly engaging the manual valve. You may need to drop the valve body in order to adjust the height of the detent plate to get the arm to seat between the two stops on the manual valve (if the arm interferes with the outer stop). Check to make sure the detent ball and spring on the rooster comb are properly seated in the bore when doing this.

 

[dvw]

I'm assuming you removed the E clip to change the throttle lever seal. When this was done the kickdown shaft dropped and the rooster comb moved up. Most likely the detent ball and spring popped out when the rooster comb moved upward. Then the arm was no longer inserted in the manual valve groove. The manual valve selects the fluid passage to send presssure to various clutch packs and bands to create a flow path thru the planetary gear sets to create each gear. For this repair the valve body needs to come out. How did you install the rooster comb detent ball and spring when you changed the seal? Or didn't you? If not it's just setting on top of the valve body. Tell me exactly how you made the repair.
Doug

 

[Chadiator]

I'm assuming you removed the E clip to change the throttle lever seal. When this was done the kickdown shaft dropped and the rooster comb moved up. Most likely the detent ball and spring popped out when the rooster comb moved upward. Then the arm was no longer inserted in the manual valve groove. The manual valve selects the fluid passage to send presssure to various clutch packs and bands to create a flow path thru the planetary gear sets to create each gear. For this repair the valve body needs to come out. How did you install the rooster comb detent ball and spring when you changed the seal? Or didn't you? If not it's just setting on top of the valve body. Tell me exactly how you made the repair.
Doug

Thanks both! This makes a lot more sense then why I have no gears, and no park with that valve stuck in one place and the arm unable to go far enough over to engage park.

What’s bizarre is I feel like the detent ball never came out (somehow). When manually shifting at the tranny with the shift lever (by hand), I can feel the notches in the rooster click through, one by one.

When I changed the seal, the trans was out on my shop floor. I pull the kickdown and shift levers off, then popped the e-clip out, removed the washer, hooked and pulled the seal out, then tapped a new one in with a socket. I never touched any of it from the valve body side. When putting it all back together from the outside, I couldn’t slide one of the levers down the shaft far enough, nor could I see the notch for the e-clip, which is the only moment when I realized that the shaft could move vertically (live and learn, haha). At that point, I pulled it up to where it needed to be, and got it all back together.

Now in hindsight knowing how all this goes together, I am really puzzled as to how this all happened and that ball potentially stayed in. Sounds like in either case though, pulling the valve body is going to be the safest bet to make sure everything else is good!

Currently looking to see if I can find a local pan with a drain plug after last nights mess

 

[hofferwood]

I bought this little pump, right down the fill tube, works great.

Amazon.com

 

[turbine68rt]

Sounds like in either case though, pulling the valve body is going to be the safest bet to make sure everything else is good!

Easiest way to work on it, as well as confirming the detent assembly is functioning properly.

 

[Chadiator]

Happy to report we now have gears and parking back! Thats all it was; lever needed to hook into the valve again.

The ball on the rooster was still in place when I pulled the valve body, too! Surprisingly

 

[turbine68rt]

Had a feeling it may have been that.

 

[oldkimmer]

Glad got it fixed. Kim