727 BB Planetaries

-
80fbody

80fbody

Well-Known Member
Joined
Apr 9, 2011
Messages
710
Reaction score
133
Location
Belchertown, MA
Is it common to have a 4 pinion front with a three pinion rear planetary? Do I need to look for another rear?

500-550hp Strip Only
 
I've seen it in a bunch of them. I don;t think you have to worry about it at your level. You're better served by an aftermarket billet clutch retainer and Super Sprag.
 
Thanks guys.

I did purchase a bolt-in sprag before I knew better. Going to run it this year. I've got the Sonnax servos & HD band strut. Will look into the clutch retainer as well.
 
The billet retainer is the part that holds the springs, correct?

How many springs would be recommended with a 4 clutch setup & manual valve body?
 
80fbody said:
The billet retainer is the part that holds the springs, correct?

How many springs would be recommended with a 4 clutch setup & manual valve body?
Click to expand...

It's actually a billet clutchpack drum that you need (The part that explodes when the sprag lets go)
If you are referring to a spring retainer, then I don't see that as a necessary part.
The sprag, or one way clutch in the rear of the trans and the billet front drum are the important ones to help keep it from exploding.

The amount of springs in the drum can vary just from personal oppinion, but 12 is what we used to use.
Now with a manual valve body that could need to be different, and I don't know that answer. Sorry

Tracy would though, (Fishy68)
 
I was told the front Sonnax servos do not work well from someone that has done a lot of testing. This was an email reply when I asked why.


The problem with the Sonnax front servo is that is causes excessive 2-3 shift overlap. The way that they made the servo to increase the holding power of the front band, also causes it to release slower when 3rd gear applies. As you probably know, 727's are known to have 2-3 shift overlap problems when they are stock, the Sonnax front servo makes that problem much much worse. There is no way to modify the servo, the only thing you can do to help band aid the problem is install a low ratio lever (I would recommend a 2.9), install all 15 springs in the front clutch pack, and run as much front clutch clearance as you possibly can. I would highly recommend that you find a original early Chrysler servo with both the inner and outer springs and use that instead, you will be much better off.
 
gremlin said:
I was told the front Sonnax servos do not work well from someone that has done a lot of testing. This was an email reply when I asked why.


The problem with the Sonnax front servo is that is causes excessive 2-3 shift overlap. The way that they made the servo to increase the holding power of the front band, also causes it to release slower when 3rd gear applies. As you probably know, 727's are known to have 2-3 shift overlap problems when they are stock, the Sonnax front servo makes that problem much much worse. There is no way to modify the servo, the only thing you can do to help band aid the problem is install a low ratio lever (I would recommend a 2.9), install all 15 springs in the front clutch pack, and run as much front clutch clearance as you possibly can. I would highly recommend that you find a original early Chrysler servo with both the inner and outer springs and use that instead, you will be much better off.
Click to expand...

Sprung servos add to the overlap problem (they let go of the band slower), and thats why the kits advise to remove them and add something like washers to block that cushion effect if you are going to be doing manual shifting instead of fully automatic.
There is a servo fluid release port that can be opened up to speed it up also, but you could probably get around it with clearances like you said.
 
You must log in or register to reply here.
-

Back
Top