727 Modification questions

[63Fury]

I have used the 5.0 shift lever on 727 and 904 transmissions with manual valve bodies and have not had any problems. Besides the time my shift cable failed mid shift and the 904 trans ended up in 2nd and 3rd at about 5 grand, that smoked the front cluch pack real quick.

Anyway I just read that the 5.0 lever should not be used with an automatic shifting valve body, and should only be used with a full manual VB. It had something to do with the slow release of the 5.0 lever and the apply of the front clutch it said the shift overlap was to long and would smoke the front clruch at low miles. I asked a trans tech guy I know about this and he said that the shift overlap part was true but he said he has run the 5.0 lever with auto shifting VB without any problem as long as one of the following was also done.
First he said if he is doing a complete rebuild and taking the front clutch apart anyway than all he dose is install all 15 springs in the clutch. He said this extra spring pressure will slow the engagement of the cluch and reduce the shift overlap.
Second he said if he is just installing a shift kit and 5.0 lever and not rebuilding the trans (in other words he cant install the extra springs in the pack) he installs an oriface plug in the case at the front clutch apply circuit. I think he said it is a plug with a .125 hole drilled in it. It serves the same purpose to slow down the engagement of the clutch and reduce the shift overlap.
Anyway I just wanted to get you guys opinion on if this is sound advise.
I have about 30 of these extra springs from doing transmission teardown but I noticed that they are ywo different heights. I think the pre 65 72 used the taller ones. Are either of the springs better than the other.
Thanks

[John Kunkel]

The front clutch, front band and servo don't know what type of VB is installed, the VB just routes the fluid to the servo and clutch so the manual versus modified auto VB shouldn't affect lever choice.

I agree with your trans guy about the springs and it's also a good idea to load the servo with the heaviest springs available to help speed the release.

The control orifice is good for a trans that's already assembled, the orifice size can be changed without removing/disasembling the trans.

There are two different length front clutch springs, 1.4" and 1.6"; the 1.6" was used prior to '67 and is the weaker of the two. Use the 1.4" springs for maximum pressure.

[63Fury]

Originally Posted by John Kunkel

The front clutch, front band and servo don't know what type of VB is installed, the VB just routes the fluid to the servo and clutch so the manual versus modified auto VB shouldn't affect lever choice.

I agree with your trans guy about the springs and it's also a good idea to load the servo with the heaviest springs available to help speed the release.

The control orifice is good for a trans that's already assembled, the orifice size can be changed without removing/disasembling the trans.

There are two different length front clutch springs, 1.4" and 1.6"; the 1.6" was used prior to '67 and is the weaker of the two. Use the 1.4" springs for maximum pressure.

John
Thanks. On my 63 I'm just finishing the 440 to replace the 383 and when I pull it I'm going to open the 727 back up to install a kevlar KD band and 5.0 lever, I'm also upgrading to red line clutches.

The trans is a pre 65 cable 727 so I when the front clutch is out I should put all 15 short springs in that clutch? If I do this I do not need to install an oriface in the clutch circiut... correct?
Also I have a high pressure front servo spring left over from a trans go kit so I should install that spring?
Thanks again.

[John Kunkel]

If you have a servo spring left over from a TransGo kit it's for the rear servo.

The early front servo with the small (5/16") plunger could have either one or two springs while the later large plunger (5/8") servo has only one spring.

To install 15 springs you will need a piston with 15 "teats", most only have 10. Photo #27 in my photo album shows the difference.

http://albums.photo.epson.com/j/Albu...&a=13489738&f=


With 15 short springs there should be no need for the restricter orifice.

[hotrod7043]

Dave call Dynamic Trans In Brandford ct He has some Nice sealing rings and other Low buck goodies for 727s 230-315-0138 ask for Harold

[hotrod7043]

Dave call Dynamic Trans In Brandford ct He has some Nice sealing rings and other Low buck goodies for 727s 230-315-0138 ask for Harold