Jeff's 727 rebuild thread

-
Ok.....the damage

A lug on the the rear band broke off, allowing the apply lever to overtravel, allowing the rear servo piston to overtravel forcing the spring retainer to bend past the snap ring. ....UGH.

image000001-4.jpg

image000001-3.jpg
image000001-2.jpg

image000001.jpg


So.......why did the lug break? Something I did wrong on assembly?
Obviously I'll have to disassemble the transmission again to replace the band.....

I should have the transmission out today or tomorrow and on my bench.....

@KickDown ?????

Jeff
 
Wow! Bit of a bummer there Jeff. If you could adjust the band with no issues after assembly, I would say you did nothing wrong. It's not one of the things that you can do a bit wrong. Either you cocked it right up, in which case you wouldn't have been able to set up the band adjustment anywhere near right, or you set it up ok with the correct free play & an inferior quality band let go, which is my suspicion. The low reverse bands in these transmissions are very robust but at the same time the least used. Only manual low & reverse. Pain is having to strip the transmission completely again to change the band. But it all adds to experience. Keep up like this & you'll be able to do them in your sleep.
 
Thanks kickdown. ....new band is ordered...
I still have the issue of the transmission not starting in first when I put it in drive...most likely something wrong with the valve body. .....

Jeff
 
Thats exactly what happened to mine! But mine did it after 4 yrs of beating the piss out of it on the street/strip. Sucks pull it out start over, at least its fresh in your head.
 
I think the band/adjustment was causing the issue at this point.
I'm just hoping its not too high in the line pressure that caused it to fail?
But I'm more in alignment with KickDown, that this might have been more of a parts failure / Out of Adjustment Symptom
 
No sweat Jeff! Just handle one issue at a time. While you are waiting for the band to arrive, pull the transmission apart & throw that rear band as far away as you can. Once the new band is in you can study the valve body.
 
racerhog said:
I think the band/adjustment was causing the issue at this point.
I'm just hoping its not too high in the line pressure that caused it to fail?
But I'm more in alignment with KickDown, that this might have been more of a parts failure / Out of Adjustment Symptom
Click to expand...
When I put it in reverse, before it failed, it engaged VERY firmly. .....

Jeff
 
KickDown said:
No sweat Jeff! Just handle one issue at a time. While you are waiting for the band to arrive, pull the transmission apart & throw that rear band as far away as you can. Once the new band is in you can study the valve body.
Click to expand...
Thanks......I really appreciate all the help. .....

Jeff
 
MrJLR said:
When I put it in reverse, before it failed, it engaged VERY firmly. .....

Jeff
Click to expand...
I assume the car was at standstill when you selected reverse. If so, the internals of the transmission with the exception of the pump are also at a standstill & therefore not able to cause a harsh reverse shift, which leaves open the question, how high is your idle speed? I noticed your converter is red. Is it a Hughes? High Stall?
 
KickDown said:
I assume the car was at standstill when you selected reverse. If so, the internals of the transmission with the exception of the pump are also at a standstill & therefore not able to cause a harsh reverse shift, which leaves open the question, how high is your idle speed? I noticed your converter is red. Is it a Hughes? High Stall?
Click to expand...
Idle is around 850 and it's a Hughes 2400 stall......
When it broke, I was at idle, full stop, in my garage.....
At least I wasnt 50 miles away somewhere!

Jeff
 
MrJLR said:
When I put it in reverse, before it failed, it engaged VERY firmly. .....

Jeff
Click to expand...
That probably the moment it broke..
Just food for thought. Lets say, If the band was set loose, then the slop gives all the moving parts a good running start before it all comes to a sudden halt. and then the band ears get the hammer of it all.
But i'm still putting my money on the band had a defect... Not the installer... :poke:
 
racerhog said:
That probably the moment it broke..
Just food for thought. Lets say, If the band was set loose, then the slop gives all the moving parts a good running start before it all comes to a sudden halt. and then the band ears get the hammer of it all.
But i'm still putting my money on the band had a defect... Not the installer... :poke:
Click to expand...

I considered that......but I think my work was perfect :poke:
LOL

Jeff
 
MrJLR said:
Idle is around 850 and it's a Hughes 2400 stall......
When it broke, I was at idle, full stop, in my garage.....
At least I wasnt 50 miles away somewhere!

Jeff
Click to expand...
The Hughes 24-25 is the converter that I install & recommend for a typical 90% street driven car with a bit of fun now & again at the 1/4 mile. I've had no complaints & personally think it is a very good all round converter.
Yeah, that is a consolation, that it happened at home & not at 3.00AM in the pouring rain in the middle of nowhere with no cell phone network. Still sucks but you'll nail it.
 
I was rolling forward at idle,hit reverse and popped the band.
It was a cast one also. I replaced it with the strap steel one.

My power wagon has the strap steel one,abused the heck out of it while plowing snow.
 
Tooljunkie said:
I was rolling forward at idle,hit reverse and popped the band.
It was a cast one also. I replaced it with the strap steel one.

My power wagon has the strap steel one,abused the heck out of it while plowing snow.
Click to expand...
I ordered the strapped steel version :thumbsup:

KickDown said:
The Hughes 24-25 is the converter that I install & recommend for a typical 90% street driven car with a bit of fun now & again at the 1/4 mile. I've had no complaints & personally think it is a very good all round converter.
Yeah, that is a consolation, that it happened at home & not at 3.00AM in the pouring rain in the middle of nowhere with no cell phone network. Still sucks but you'll nail it.
Click to expand...
I'll have the last couple of items unbolted and the transmission on the bench this morning. ....
I like that converter at around $400.....good unit.
Let the fun begin. ...again!

Jeff
 
Just waiting for the sun to come up. ......
Regarding my shift issue, do you really think it's the valve body or as some have suggested, the govenor ?

Jeff
 
The only way to be 100% sure is to plug a pressure gauge into the govenor pressure tap at the rear of the case. (see the photo in Tom Hand's book page 39) At stand still govenor pressure should be 0 psi, steadily increasing as speed rises. I had a 68 Charger owner come to me with exactly the same fault about 2 years ago. His transmission had been in storage for 5 years without any fluid. There were 2 check balls in the VB that had been put in the wrong places, but it turned out that it was a stuck 1-2 shift valve. Dont forget the photos once you get the VB seperated Jeff! I cant really imagine that it is govenor related unless you have an internal leak from the VB into the govenor circuit & back to the 1-2 shift valve holding the valve in 2nd gear position at a stand still.
 
Last edited:
KickDown said:
The only way to be 100% sure is to plug a pressure gauge into the govenor pressure tap at the rear of the case. (see the photo in Tom Hand's book page 39) At stand still govenor pressure should be 0 psi, steadily increasing as speed rises. I had a 68 Charger owner come to me with exactly the same fault about 2 years ago. His transmission had been in storage for 5 years without any fluid. There were 2 check balls in the VB that had been put in the wrong places, but it turned out that it was a stuck 1-2 shift valve. Dont forget the photos once you get the VB seperated Jeff!
Click to expand...
For sure on the pictures.....and I guess if I (we) can't find fault with the valve body, I'll have to look into the govenor. ...I don't want to have to pull the transmission a third time!

Jeff
 
What convinces me that it is the VB & not the govenor, is when you select D at a stand still, fluid pressure is only directed to the rear (forward) clutch & to no other actuating component. This clutch is connected via the friction plates to the front planetary annulus or ring gear. As 1st gear uses the combined reduction of both planetaries, the rear drum will try to turn in a counter clockwise direction. It is prevented from doing so by the 1 way roller clutch (sprag) This causes the rear planetary annulus to turn clockwise at a reduced speed. The rear annulus is splined to the output shaft which obviously also turns at reduced speed giving 1st gear. To get 2nd gear fluid pressure must be directed to the intermediate (front) servo to apply the band, which is hydraulically impossible when the car is stationary. But we'll see. A hydraulic system can be full of surprises!! I hope I didn't lose you.
 
KickDown said:
What convinces me that it is the VB & not the govenor, is when you select D at a stand still, fluid pressure is only directed to the rear (forward) clutch & to no other actuating component. This clutch is connected via the friction plates to the front planetary annulus or ring gear. As 1st gear uses the combined reduction of both planetaries, the rear drum will try to turn in a counter clockwise direction. It is prevented from doing so by the 1 way roller clutch (sprag) This causes the rear planetary annulus to turn clockwise at a reduced speed. The rear annulus is splined to the output shaft which obviously also turns at reduced speed giving 1st gear. To get 2nd gear fluid pressure must be directed to the intermediate (front) servo to apply the band, which is hydraulically impossible when the car is stationary. But we'll see. A hydraulic system can be full of surprises!! I hope I didn't lose you.
Click to expand...
Well that is good news....and considering all the parts in a valve body verses the govenor, it's far more likely I screwed something up in there!
I will CAREFULLY disassemble it and photograph every bit so you can help me diagnose what happened. ....

Jeff
 
Ok....new rear band, can' get the lug in.
Are there different length lugs or...???
This is very strange. ....

Jeff
 
You must log in or register to reply here.
-

Back
Top