How Many Front Planetary Pinions?

-

Ricks70Duster340

Child of the King
FABO Gold Member
Joined
Feb 8, 2021
Messages
1,232
Reaction score
975
Location
Sisterdale, TX
I have a '70 A727 that is original to a 340 and still installed in the car. Need to know if anyone knows if it came with 3 or 4 planetary pinion gears. I know the big block 727's came with 4.
 
I found this in a discussion on rebuilding a 727
. The large cast-alloy pan holds more fluid and bridges the open section of the transmission case to provide extra strength. The front planetary gearsets in small-block Torqueflites are three-pinion gearsets, while the big-block version has stronger four-pinion front planetaries.

Three- and four-pinion types are directly interchangeable. A four-pinion planetary handles about 33 percent more torque than the three-pinion version
 
Last edited:
I have several BB 727 transmissions and all have 3 planetary gears. I believe it to be Hemi and Motorhome transmissions had the 4 planetary sets. Could be wrong, but that is my experience.
 
I have several BB 727 transmissions and all have 3 planetary gears. I believe it to be Hemi and Motorhome transmissions had the 4 planetary sets. Could be wrong, but that is my experience.
Are your tranmissions 60's-early 70's era before Big Brother?
 
I found this in a discussion on rebuilding a 727
. The large cast-alloy pan holds more fluid and bridges the open section of the transmission case to provide extra strength. The front planetary gearsets in small-block Torqueflites are three-pinion gearsets, while the big-block version has stronger four-pinion front planetaries.

Three- and four-pinion types are directly interchangeable. A four-pinion planetary handles about 33 percent more torque than the three-pinion version
I definitely want a 4 pinion one. Will go on the hunt. Thanks for the replies!
 
Are your tranmissions 60's-early 70's era before Big Brother?

Later ones. I rebuilt one which had the 3 planetary gears and installed the 4 planetary gearset from a motorhome trans.
 
I definitely want a 4 pinion one. Will go on the hunt. Thanks for the replies!

Motorhome ones have (all I have seen and heard of) have the 4 planetary sets. They are cheap to pick up as all need output shaft and extension housings to work in our cars.
 
No, still in the car. Have a different engine coming soon, so want to pull the tranny and have it gone thru to ensure it has the beef I need.

You may possibly already have one. I wouldn't take everything on here as gospel. 340 stuff was known to be more heavy duty.
 
You may possibly already have one. I wouldn't take everything on here as gospel. 340 stuff was known to be more heavy duty.
We're just throwing things out there, no one is saying it's gospel. Just communicating.
 
A buddy blew his on his 70 Bee 727. He replaced it with a billet one and a bolt in sprag.
Ugh. Certainly could go top shelf but would need some deep pockets!!!
We're just throwing things out there, no one is saying it's gospel. Just communicating.
Thanks guys. The proof will be in the teardown! Onward!
 
I knew they are aftermarket, but it ran through my head as to what sun gear they would use. When I changed my 904 to a 4 pinion & the /6 lower 1st gear, I was missing the correct sun gear which is a different size than the 3 pinion. I went to a local transmission shop & the owner gave me the correct one.
 
We're just throwing things out there, no one is saying it's gospel. Just communicating.

I understand. I would just hate to see him run out and buy something that he might already have.
 
340 would have had a 4 pinion planet in the front I believe. I think only the HP big blocks would have 4 pinion.
 
You don’t need them until over 600 horsepower. Now there are 2 planetaries in a 727 and the front is more common than the rear in 4 pinions. All BB 727’s do not have both 4 pinions. Only 440 HP, hemi and some truck & motorhome. 383’s don’t have them either.

you cannot just swap in some planetaries, there are different spline angle on the output shaft depending on year. I don’t have the breakdown on that but beware of it when swapping.

I don’t know what a 340 has, but since it is a small block and not as much torque or weight as a 440 car it may not have them at all.
 
Last edited:
I have been in many 340 transmissions and always just the one 4 pinion, the other 3. I believe it was the front that was 4.
I used to think that the big block trans all had them but was sadly disappointed.
 
I have a '70 A727 that is original to a 340 and still installed in the car. Need to know if anyone knows if it came with 3 or 4 planetary pinion gears. I know the big block 727's came with 4.
I have a 4 pinion planetary carrier out of a 6 BBL RR car 727 TorqueFlite. It also has a larger 2nd gear clutch drum* (2nd is a band, but the drum also houses the 3rd speed clutch) so I call it a clutch drum. Anyway it's bigger but my trans guy says the double wrap band on the smaller drum is all he thinks is necessary. I believe a 727 is a 727 is a 727 regardless of having an "A" bell or a Slant 6 bell, it's a 727. So you can stuff it with anything a 727 takes. I have heard there is also a 5 pinion planetary carrier as well, but I believe it's aftermarket, as I never heard of one stock.(I lived thru that era, I'm 72) But if you really want to know, get with someone who runs in the 1968 only HEMI A Body class, they are using 904 parts! I ain't too sure of the name of that class, but they only allow the 1968 Dart and Barracuda. Something like: The Hemi Challenge, or SS/AH cars, or Nostalgia Super Stock. I've seen them several times but I'm getting old and cannot remember exactly what they are called. They are ALL HEMI, and ALL TORQUEFLITE and only 1968 Darts & Barracudas. Hope this helps.
 
Last edited by a moderator:
-
Back
Top