727 issue reverse

[19Charger74]

Ok so I have a issue with my 727 trans now. I backed out of the driveway and then when I went to park it in the back garage I had no reverse.....1-2-D work but nothing in reverse.

I pulled the pan off and the oil looked dirty but the bands were fine and I adjusted the rear band a little tighter. When I had the car on the hoist I noticed that rotating the tires backwards( like reverse) it took more strenght to move then. I check this out in reverse gear/nuetral and in 1-2 gear, they all felt the same.

Could it be a dirty filter? to high of rpm at idle to click over into reverse? maybe the valve body is toast?

I had the correct amount of fluid in there and it worked fine.

 

[mopwrd340]

warm the car up and if it goes back ward the reverse servo seal is bad not to hard to replace.

 

[19Charger74]

Ok so my update lol been awhile. I looked inside and noticed the reverse band was alittle loose so i tightened it to stock 727 reverse spec and it went into revese.

mopwrd340 - How will you know the reverse servo seal is bad?

 

[mopwrd340]

usually the car wont back up when its cold and if you sit there with it in reverse after a minute or 2 it will start slowly backing up,

 

[19Charger74]

I got back out there today and put it in reverse and nothing happened. The engine was warmed up and the trans i assume was warmed up since if worked great in forwards.

But nothing happened in reverse. Nothing looked damaged inside the trans, not to sure what else to look for in there?

 

[SUPERSTOCKRACER]

I got back out there today and put it in reverse and nothing happened. The engine was warmed up and the trans i assume was warmed up since if worked great in forwards.

But nothing happened in reverse. Nothing looked damaged inside the trans, not to sure what else to look for in there?

rear servo seal is bad. happened to me at pinks allout at maple grove.
you have no line pressure to get into reverse.either your retainer popped free from the retainer C clip or ripped seal.you probably tightened up to much on the pressure or it was just going bad.
drop the pan, remove the valve body, and get ready to get real messy.
getting the retainer and clip back on is gonna be tuff. i had to make a tool to put the new servo back into place.
GOOD LUCK, THE JOB SUCKS with the tranny in the car.:angry1:

 

[SUPERSTOCKRACER]

heres a pic ofhow mine looked. its a weak link imo in 727 trannys

 

[19Charger74]

Thanks for the Pictures and Help!! I got out there tonight for a few minutes and loosened off the reverse lever put my finger in there and pulled out 2 pieces of aluminum chunks....i was pretty worried and got the old screw driver out and turns out the piston broke. Thanks goodness cause i have a new already lol lucky!!! anyways the cylinder walls and smooth so i think i'm going to swap these tomorrow after work and give her a test.

 

[SUPERSTOCKRACER]

Thanks for the Pictures and Help!! I got out there tonight for a few minutes and loosened off the reverse lever put my finger in there and pulled out 2 pieces of aluminum chunks....i was pretty worried and got the old screw driver out and turns out the piston broke. Thanks goodness cause i have a new already lol lucky!!! anyways the cylinder walls and smooth so i think i'm going to swap these tomorrow after work and give her a test.

engine piston or servo piston/:hmh:

 

[19Charger74]

I blew the reverse servo piston lol i was kinda worried because i put my finger up there and brought back 2 pieces of aluminum. First thing in my head was THE CASE!!! lol anyways just piston. So i pulled the valve body off and poped out the reverse lever pin and pulled out the old and put in the newer one from another 727 i had.

Now for anyone else with this issue, you dont need to pull out the valve body or pull the tail shaft out so remove the lever arm. To do this i cut the tail stock lip that stopt he lever arm pin from coming out. ( Zip cut disc) after this i found another longer bolt and simple cut a piece of steel in a "L" shape with a hole fo rthe bolt to go through. Put that one the long bolt with a nut to hold the plate down and BAM! Quick simple job.

Thanks for all the help guys! really appreciate it!

 

[mopwrd340]

you cheated the last one i did was on a fifth ave couldnt get the cover off for the tail shaft snap ring took the bolts off for the tail shaft and rotaded out of the way , gasket didnt tear and i put it back together older fwd cars use the same seal and no need to pull a tailshaft .

 

[racedodge]

if you blew the rear servo piston retainer then you would not have 1st gear either as both gears use the rear band for engagement.

the reason your piston servo broke is because your band was not tightened appropriately or your rear band has begun wearing to a point where you are losing band material OR band, itself, is beginning to show signs of metal fatigue. the rear servo piston failing is just a symptom of the real problem. not saying its a huge, dire issue, but something not to be taken lightly.

good luck.

 

[SUPERSTOCKRACER]

I blew the reverse servo piston lol i was kinda worried because i put my finger up there and brought back 2 pieces of aluminum. First thing in my head was THE CASE!!! lol anyways just piston. So i pulled the valve body off and poped out the reverse lever pin and pulled out the old and put in the newer one from another 727 i had.

Now for anyone else with this issue, you dont need to pull out the valve body or pull the tail shaft out so remove the lever arm. To do this i cut the tail stock lip that stopt he lever arm pin from coming out. ( Zip cut disc) after this i found another longer bolt and simple cut a piece of steel in a "L" shape with a hole fo rthe bolt to go through. Put that one the long bolt with a nut to hold the plate down and BAM! Quick simple job.

Thanks for all the help guys! really appreciate it!

hey, any change you can put up a few pics of what you made up for the install. l shaped bracket. im curious to see how yours worked so easy. please!!:headbang:

 

[19Charger74]

Hey, No problem I'll post pictures wednesday night or day.

Yes, the rear band is probally on its way out. When i got in there and adjusted the rear band to the specs, i noticed about (alteast) 1/4" of change. Enough that i redid it 2 times.

For the rear band, i'll end changing it over the winter maybe and also the front band. They have new flexible bands so you can slip them in and around the drums. I'm going to see if i can do this on my parts transmission to see if the bands break when flexed so i know if i can do this with out removing the transmission.

 

[19Charger74]

Alrighty i was driving the other day, did a burn out real quick and now the trans is F%$#@! again.

It wants to roll forward in nuetral and reverse nothing happens but the engine feels to be under load when i rev it up. "What I've done"- Pulled the pan, nothing in the pan bottom, bands are fine, rear servo is fine, bands set to factory 727 specs. Pulled the valve body out cleaned it and checked for metal balls in correct location. I checked the pressure piston in the VB and its spec'd out correctly, the kick down linkage was set up correctly.

Does anyone have any thoughts? the oil passages in the trans case i could see i cleaned out.

 

[mferraro76]

Alrighty i was driving the other day, did a burn out real quick and now the trans is F%$#@! again.

It wants to roll forward in nuetral and reverse nothing happens but the engine feels to be under load when i rev it up. "What I've done"- Pulled the pan, nothing in the pan bottom, bands are fine, rear servo is fine, bands set to factory 727 specs. Pulled the valve body out cleaned it and checked for metal balls in correct location. I checked the pressure piston in the VB and its spec'd out correctly, the kick down linkage was set up correctly.

Does anyone have any thoughts? the oil passages in the trans case i could see i cleaned out.

other than obvious things like low fluid, and assuming you are only slipping in reverse - per ATSG some suspects are: pressure too low, reverse band out of adjustment, valve body malfunction, faulty oil pump, worn or broken reaction shaft support seal rings, worn or faulty front clutch, lw reverse servo or band malfunction.

i had a 904 go bad, i lost reverse one day and eventually 3rd gear started to slip - are you slipping in any other gear?

i agree with racedodge, there are likely internal issues resutling in other part failure. you should probably have it checked out before it strands you somewhere.

 

[19Charger74]

I took it around the block anyways. After it warmed up, the whole trans started slipping.
1st was real bad i had to rev it up to 3grand then it would click/catch and go. 1-2 shift was real sluggy/slow and 3rd clicks in nicely lol

I think i'm going to have to park the car for the year and have the trans rebuilt lol

Thanks for all the Help!

 

[dvw]

if you blew the rear servo piston retainer then you would not have 1st gear either as both gears use the rear band for engagement.

the reason your piston servo broke is because your band was not tightened appropriately or your rear band has begun wearing to a point where you are losing band material OR band, itself, is beginning to show signs of metal fatigue. the rear servo piston failing is just a symptom of the real problem. not saying its a huge, dire issue, but something not to be taken lightly.

good luck.

The rear band only holds the rear drum for reverse and 1st gear braking. 1st will still function using the low roller clutch and forward (rear position in the case) clutch. Rear bands seldom wear out.
Doug