727 leak at rear and not sure how to fix (2024)

Nov 14, 2023

Justasgood

Well-Known Member

Local time: 6:33 PM

Joined: Jul 14, 2023

Messages: 174

Reaction score: 427

Location: Covington, La

So my Torqueflite 727 has an ongoing seepage at the rear tail area. It looks like someone filled a hole with Silicone(?) and it continues to allow fluid to seep.

What was this hole intended for and is there something missing or needed?

Best way to address this?

Searching online only shows what I think is a “Packing Lock assembly”? Perhaps that is a Parking lock assembly?

Anywho, any insight or suggestions would be greatly appreciated.

Thanks,

Kurt

Nov 14, 2023

icetech

Well-Known Member

Local time: 7:33 PM

Joined: Jun 2, 2022

Messages: 1,303

Reaction score: 1,418

Location: Macomb Mi

This should be your issue.. can fix it in car, will take 2 hours or so..

727 leak -what’s this?

This leak is from the back side of the transmission body. The bolt head is bolting the tail section to the main body and the leak is at that found thing just below. What’s the round thing and what’s the fix?

www.forbbodiesonly.com

Nov 14, 2023

Justasgood

Well-Known Member

Local time: 6:33 PM

Joined: Jul 14, 2023

Messages: 174

Reaction score: 427

Location: Covington, La

So if I drain the fluid, remove the existing silicone and clean and dry the area, can I reseal from the exterior with something like “The right stuff”?

Nov 14, 2023

Rebelrouser

Well-Known Member

Local time: 6:33 PM

Joined: Oct 18, 2022

Messages: 193

Reaction score: 334

Location: Bland Missouri

The area you mention is the pin that holds the rear band, it is supposed to have an O-ring on it. Lot of guys myself included put a dab of silicone just to make sure it does not leak. To pull it completely out you will have to remove the valvebody to gain access to the band strut to line it up correctly when you put the pin back in. You should be able to clean really good and silicone it again and it should stop leaking if it is the pin hole leaking. It should only leak when the engine has been shut off for a while and the converter drains into the case, while running the fluid should be below the pin hole.

Nov 14, 2023

Car #4

Well-Known Member

Bee1971

Well-Known Member

Local time: 6:33 PM

Joined: Jun 22, 2017

Messages: 2,460

Reaction score: 3,509

Location: Sobieski

It’s not a hard job - Just a messy job on your back - Lift sure would bee nice

You have to remove the tail shaft housing bolts and rotate the tail shaft for the tab to clear the pin
You DO NOT have to remove the tail shaft , unless I guess somehow the gasket got stuck or got damaged

Any linkage on the tail shaft remove

My local transmission shop gave me a used newer double style pin and the proper o-rings

I guess I reality I didn’t want to use silicone

Nov 14, 2023

icetech

Well-Known Member

Local time: 7:33 PM

Joined: Jun 2, 2022

Messages: 1,303

Reaction score: 1,418

Location: Macomb Mi

Bee1971 said:
It’s not a hard job - Just a messy job on your back - Lift sure would bee nice
You have to remove the tail shaft housing bolts and rotate the tail shaft for the tab to clear the pin
You DO NOT have to remove the tail shaft , unless I guess somehow the gasket got stuck or got damaged
Any linkage on the tail shaft remove
My local transmission shop gave me a used newer double style pin and the proper o-rings
I guess I reality I didn’t want to use silicone
View attachment 1556960
View attachment 1556961
Click to expand...

I didn't know you could just rotate the tailshaft, very good to know

Nov 14, 2023

Justasgood

Well-Known Member

Local time: 6:33 PM

Joined: Jul 14, 2023

Messages: 174

Reaction score: 427

Location: Covington, La

Lift - check
Where can I get the double 0-ring pin?

Nov 14, 2023

zyzzyx

FBBO Gold Member

FBBO Gold Member

Local time: 6:33 PM

Joined: Aug 5, 2011

Messages: 3,704

Reaction score: 5,326

Location: Lisle, Illinois

Just remember to remove your speedometer pinion because if you break it while moving the tailshaft backwards
it will be a P.I.T.A!

Nov 14, 2023

Justasgood

Well-Known Member

Local time: 6:33 PM

Joined: Jul 14, 2023

Messages: 174

Reaction score: 427

Location: Covington, La

Part name of Pin?

Nov 14, 2023

1 Wild R/T

FBBO Gold Member

FBBO Gold Member

Local time: 4:33 PM

Joined: Jul 9, 2019

Messages: 10,157

Reaction score: 27,253

Location: California

Justasgood said:
Part name of Pin?
Click to expand...

Rear band anchor pin

Nov 14, 2023

Justasgood

Well-Known Member

Local time: 6:33 PM

Joined: Jul 14, 2023

Messages: 174

Reaction score: 427

Location: Covington, La

Can these be found with the double o-rings?

Nov 14, 2023

Bee1971

Well-Known Member

Local time: 6:33 PM

Joined: Jun 22, 2017

Messages: 2,460

Reaction score: 3,509

Location: Sobieski

zyzzyx said:
Just remember to remove your speedometer pinion because if you break it while moving the tailshaft backwards
it will be a P.I.T.A!
Click to expand...

I didn’t even remove the speedometer cable when I rotated the tail shaft housing - You only have to rotate it slightly , not pull back

Nov 14, 2023

1 Wild R/T

FBBO Gold Member

FBBO Gold Member

Local time: 4:33 PM

Joined: Jul 9, 2019

Messages: 10,157

Reaction score: 27,253

Location: California

I've been rebuilding torqueflites on the side since the seventies... I've seen exactly one pin with the double O ring grooves.... It was from a mid eighties truck...

The reality is the single O rings are fine if they are less than twenty years old... Lots of younger rebuilders neglect to change the O cause they don't realize it's there...

If you pill the pin to swap it you could just put an O ring on the existing pin & you'll be find....

Or do what most guys do, drain a little fluid, clean it really well with brake clean & compressed air.. And fill the hole with silicone, allow to dry overnight & refill with fluid...

That's usually good for years but depending on how good of a job you do it does slowly breakdown & fail..

If you've gotta have two O rings a few minutes on a lathe & you'll be all set...

Nov 14, 2023

R413

Well-Known Member

Local time: 4:33 PM

Joined: Feb 4, 2019

Messages: 6,002

Reaction score: 17,721

Location: NW USA

Justasgood said:
Lift - check
Where can I get the double 0-ring pin?View attachment 1556994
Click to expand...

You don’t really need the double o ring pin, but it won’t hurt. It’s probably a 50 year old oring in your pin. Nobody ever changes the Oring.

if you are going to rotate the rear housing then remove the speedo gear so it doesn’t get damaged. DAMHIK

Last edited: Nov 14, 2023

Nov 14, 2023

icetech

Well-Known Member

Local time: 7:33 PM

Joined: Jun 2, 2022

Messages: 1,303

Reaction score: 1,418

Location: Macomb Mi

I "Think" i replaced my o-ring... been afraid to fill the trans yet.. cable shift trans with sooo many spots waiting to leak

Nov 14, 2023

Bee1971

Well-Known Member

Local time: 6:33 PM

Joined: Jun 22, 2017

Messages: 2,460

Reaction score: 3,509

Location: Sobieski

Chrysler

Page 61- Figure 96

https://atoc.ru/uploads/manual/5fb79d619e567.pdf

Last edited: Nov 14, 2023

Nov 14, 2023

493 Mike

FBBO Gold Member

FBBO Gold Member

Local time: 7:33 PM

Joined: Dec 25, 2011

Messages: 5,366

Reaction score: 6,533

Location: White Cloud, MI

Years ago I cut off the tab that retains the pin, dropped the VB and knocked the pin out to R&R the O-ring. Fabbed a different retainer to secure the pin. The next time the trans was out I swapped extensions back to OEM condition. I do not remember why I did not remove the extension in the first place except I was on my back doing the work? I still have 20 or so TF cores so extensions have become just more "parts".
Mike

You must log in or register to reply here.