My first 727 rebuild, challenges, questions.

My first rebuild attempt is not turning out as I had hoped. After a short drive it's got reverse and low gear only. After much research I bought a gauge to check pressures. I have the back wheels off the ground. In drive the governor pressure never gets to 20psi even when the engine speed is above 4000rpm. I checked the line, front and rear servo pressures. They all read 0, in every gear and any throttle lever position. I don't know why the car moved. I installed a Superior shift kit if that makes a difference. Also I did stand the trans up on the output shaft to get the TQ on. One post I read said this could cause an issue.

Can Moparts please help me understand what's happening?

Thanks

In first gear you will not have any pressures at the front servo or rear with the shifter in D.

You should have pressure at the rear servo in manual low and reverse.

Most valve bodies should produce line pressure at the middle port on passenger side in all forward position.

I would pull the extension housing and see if the governor weight and valve are stuck before anything else.

Use a low pressure gauge for the governor - not a 300 pounder.

Possibly something wrong in the VB too.

Governor pressure is tied to wheel speed, not engine speed. Faster the wheels turn the higher the gov. pressures.

Added info - since the gov. pressure doesn’t increase past 20 that should be investigated further.

Not sure how deep you got inside the trans, if you pulled the output shaft and such. If so, then see my note below regarding the gov. seal rings.

Thanks for the reply. The speedometer doesn't work so I ran the engine up to 4000 rpm with the trans in drive. It never shifted, the governor pressure built as I increased engine rpm, and wheel speed, but stopped increasing at a much lower rpm.

I will start taking the tail shaft off tomorrow.

There are two metal seal rings on the governor support - not visible when the governor housing (aluminum part that has the weight and valve inside) is on the support (steel part with park sprag lugs).

In order to pull the support and housing you need to remove the governor shaft e clip, shaft, remove the weight and valve, remove the rear snap ring holding it on the output shaft, then sliding it back. Make sure the 2 metal seals are not broken or missing.

Thanks Transman.

Did you hook up/adjust the kick down lever?

my first attempt at installing a shift kit was a disaster. all i had was first and reverse.
to get my car going, i installed another known good valve body.
afterward, i went over the instructions a couple of times, and found i screwed up putting the valve body back together.
i don't remember what i did wrong, but maybe it's something like a missing ball, or a ball in the wrong place.
it wouldn't be too much effort to review what was done to the valve body and see if the problem starts there.
just something else to check. it won't cost anything but time.

Hey Moparite, yes I adjusted the kick down per the FSM.

Moparx, I have a known good VB I'm going to install.

Thanks all

The governor parts all move freely and smoothly. I installed new, cast iron sealing rings on the governor during the rebuild. The area the rings seal upon is some what polished but free from gouges and scratches. Would teflon seals be a good idea?

Next I will drop the pan, remove the VB, and air check the servos and clutches again. Then install different VB, put it all back together and try again.

please keep us informed on what the problem turns out to be.
it may help out someone else in the future.

If the trans is back together again, take it for a ride with the gauge on it.

Let us know what the pressure is at a standstill as you place it in drive, while at a standstill. Then let us know what the pressure does as you roll away from the stop.

My first youtube video. It's too big to attach. The front clutch has teflon seals, I read they leak more air.

https://youtu.be/B4BQhg1pmes

It seems like the front servo and clutch leak excessively. Please review and let me know your thoughts.

Thanks

I has almost the same issue, i was thinking about how the metal sealing rings actually seal. The channel were the sit is important also. If the are sloppy in the channel the housing can be worn. I replaced the housing and the issue went away.

I installed an known good, stock valve body and it now shifts manually and automatically into second and drive. Perhaps I hosed something up with the shift kit installation. I have also read and heard of other people having the same issue after a shift kit install. Anyway, I'm just gonna drive it now. Thanks all for your time and experience.

Thanks for the update and glad all is well

good to hear your transmission is good after the installation of a factory valve body !
as one who has "been there", when you have time, go back over the instructions and your modified valve body.
with a little patience and studying, you will be able to find what is wrong with your modified valve body. i'm betting on a misplaced, missing, or wrong size ball installed.
thanks for reporting back !