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Automatic transmission questions - Update

Started by BLK 68 R/T, December 27, 2016, 10:55:11 AM

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BLK 68 R/T

The transmission that came with my car (68 charger, 440) was previously rebuilt, sometime in the mid '90s I believe. I don't know any specifics other than it was "rebuilt." I have very limited experience with 727's so when I installed it I did not pre fill the torque converter. It also has a deep pan on it. I put about 5 quarts into it initially before I started it, although I started and ran it in park position instead of neutral. Now has about 8 quarts in it total and is full on the dipstick when idling in neutral warmed up. I tried to move the car out of the shop and it revs really high before it will try to move, like 2500-3000 rpm to get it to move, and it seems to only want to move in  1st gear and reverse.

Before I installed the transmission, I pulled the pan off of it and there were signs that mice had gotten into the transmission and built a nest in the pan. I did manage to pull the valve body out and cleaned everything up and got the linkages to all move again. The rest of the internals looked nice and clean. Also it had a brand new torque converter installed.

So my questions are:

Is it necessary to fill a new torque converter before install?
Does it sound like my torque converter is ruined?
Is it possible that the front pump in the transmission was completely dry after all these years and it burned up by being started in park instead of neutral?
Valve body - Is it defective? I did not completely disassemble it, I did not pull all the valves out, just pulled the 2 halves apart and cleaned everything.

I'm open to any feedback and any additional questions.

cdr

pull it out, take it apart & replace bad parts, get a new converter or that one rebuilt.
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
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justcruisin

I'm sure John will chime in to help, but meanwhile, the converter should be pre filled, however the pump will fill it upon start up.
Your problem could be a number of things, I would do some tests before taking it out.
Presuming you have enough fluid in the trans, make sure your linkage is set correctly, do a pressure test, ( does it sound like the trans is engaging when you put it in gear).

It could be sucking air from a leak at the valve body, drop the valve body and air check your circuits.

With forward and reverse slipping it sounds like a pressure problem of some sort.

John_Kunkel

Quote from: BLK 68 R/T on December 27, 2016, 10:55:11 AM
I tried to move the car out of the shop and it revs really high before it will try to move, like 2500-3000 rpm to get it to move, and it seems to only want to move in  1st gear and reverse.

Sounds like the overrunning clutch (sprag) has failed; when it fails the car won't want to move forward in Drive but will move in manual low because the rear band takes over for the sprag. The sprag isn't used in Reverse.
Pardon me but my karma just ran over your dogma.

BLK 68 R/T

Thanks all for the help so far on this.

So I pulled the transmission today in anticipation of a full rebuild. I pulled the valve body out today and was looking it over, I noticed that 2 of the spool valves, the line pressure and torque converter valves were seized in the bores. When I pulled the valve body apart the first time I did not tear it completely down and missed this  :slap: Lesson learned for me! I did eventually get the valves out but I think the valve body is shot. It has too much corrosion from the mice around the bores where those valves go. I'm hoping this explains the problems I was having. Figured as long as I have it out, I will pull the internals out and check them out, inspect the front pump, and look at the sprag and see if a bolt in unit was installed when the transmission was rebuilt the first time. I did the air pressure test on the 2 bands and the pistons seem to work fine. Any other things I should check??

so now I need a valve body - any suggestions? I was looking at this one from Cope Racing Transmissions, along with the associated low/reverse servo needed.
CRT 727-904 Pro Street Automatic Shift Valve Body

Or is better to try and find a used one (that works  ;) ) and put a shift kit into it?





Dino

That's nasty looking!

For a street car I like the valve body to be stock. I wouldn't want to give up the smooth shifts.
Extraordinary claims require extraordinary evidence.

BLK 68 R/T

Yea, I was almost embarrassed to post the photos, all that crud is stuck pretty good to the outside of the valve body, I scrubbed it with a wire brush in solvent and air dried it before I put it back in the first time. Should have checked all the valves, but I really didn't know what I was looking at  :brickwall:

I have since bought a book on rebuilding and modifying the 727. Super helpful and loaded with good info  :2thumbs:

Dino

I think I know which book you're referring. Good stuff!

I love how smooth my trans shifts. Under light load you can barely feel it. If it had 2 more gears I'd probably wouldn't want a manual trans in its place.
Extraordinary claims require extraordinary evidence.

c00nhunterjoe


redgum78

Quote from: BLK 68 R/T on December 30, 2016, 01:10:44 PM
Yea, I was almost embarrassed to post the photos, all that crud is stuck pretty good to the outside of the valve body, I scrubbed it with a wire brush in solvent and air dried it before I put it back in the first time. Should have checked all the valves, but I really didn't know what I was looking at  :brickwall:

I have since bought a book on rebuilding and modifying the 727. Super helpful and loaded with good info  :2thumbs:

Could you post the book title and author? I would like to learn a bit more about the good old 727 in my Charger.
Good luck with yours.

Dan

BLK 68 R/T

Quote from: redgum78 on December 30, 2016, 09:48:47 PM
Quote from: BLK 68 R/T on December 30, 2016, 01:10:44 PM
Yea, I was almost embarrassed to post the photos, all that crud is stuck pretty good to the outside of the valve body, I scrubbed it with a wire brush in solvent and air dried it before I put it back in the first time. Should have checked all the valves, but I really didn't know what I was looking at  :brickwall:

I have since bought a book on rebuilding and modifying the 727. Super helpful and loaded with good info  :2thumbs:

Could you post the book title and author? I would like to learn a bit more about the good old 727 in my Charger.
Good luck with yours.

Here you go  :cheers:
https://www.amazon.com/Torqueflite-727-Transmission-Handbook-HP1399/dp/1557883998



justcruisin

That is a great book, I would also advise to down load the FSM for your year trans if you don't already have it.

67tbird

Anybody read the Amazon description and see it said 904 transmission?

BLK 68 R/T