Question on 727 trans for 69 Charger

[bob32268]

I've noticed there are two different 727 transmissions for my 69 Charger, one is for the 383 with 2bbl and one for the 383 with 4 bbl. What are the differences ? Is the 383 4bbl trans more heavy duty than the 383 2 bbl ?
Could they interchange with no problems ?
Tks,
bob 32268

 

[Dave6T4]

Do you have a Factory Service Manual for your 1969 Charger? If so, it will show the components used in the various transmissions in the transmission rebuild section. I recently had the opportunity to rebuild a 1970 Torqueflite from a 383 HP application. It had a 4 gear planetary in the front, and a 3 gear planetary in the back. Both drums had 4 clutches. The front clutch assembly had only 6 springs in it. The kickdown servo only had the small diameter spring in it, and had a 3.8 lever with it. The governor assembly had the short inner spring, with the lighter inner weight, for a higher upshift speed.
Based on my years of rebuilding Torqueflites, in a low performance transmission, I would expect to find 3- gear planetaries front and rear, 4 clutches in both drums. The front clutch assembly would have 10 or 12 springs in it. The kickdown servo would have both the large and small diameter springs in it, with either a 2.9 or 3.2 lever with it. The governor assembly would have a longer internal spring and heavier internal weight, for a lower upshift speed. The different internal parts change the shift timing and would result in softer shifts a person would expect in a non-high performance vehicle.
The 383 HP transmission would have come with 10" high stall torque converter ( The one I worked with was stamped 2600 ). The non-HP transmission would have had a 11" low stall piece.

 

[Kern Dog]

Realistically, any 727 with the B/RB pattern will fit and work. The differences are inside and relate to durability under load. If you just drive easy, even a lighter duty version will last.

 

[dvw]

You will have no issue. The 3 pin planets will live easily to 700HP. The 4 friction front clutch is more desirable than a 3 friction. However on a stock engine the 3 plate wont be an issue if it's in good shape. It's possible both trans are 4 friction. The rest of the differences are calibration for shift timing, shift rpm and shift firmness.
Doug

 

[bob32268]

Do you have a Factory Service Manual for your 1969 Charger? If so, it will show the components used in the various transmissions in the transmission rebuild section. I recently had the opportunity to rebuild a 1970 Torqueflite from a 383 HP application. It had a 4 gear planetary in the front, and a 3 gear planetary in the back. Both drums had 4 clutches. The front clutch assembly had only 6 springs in it. The kickdown servo only had the small diameter spring in it, and had a 3.8 lever with it. The governor assembly had the short inner spring, with the lighter inner weight, for a higher upshift speed.
Based on my years of rebuilding Torqueflites, in a low performance transmission, I would expect to find 3- gear planetaries front and rear, 4 clutches in both drums. The front clutch assembly would have 10 or 12 springs in it. The kickdown servo would have both the large and small diameter springs in it, with either a 2.9 or 3.2 lever with it. The governor assembly would have a longer internal spring and heavier internal weight, for a lower upshift speed. The different internal parts change the shift timing and would result in softer shifts a person would expect in a non-high performance vehicle.
The 383 HP transmission would have come with 10" high stall torque converter ( The one I worked with was stamped 2600 ). The non-HP transmission would have had a 11" low stall piece.

Thanks for this very useful information, much appreciated.
Bob32268

 

[Dave6T4]

The two transmissions are interchangeable; that is bolt patterns and mounts are the same. For everyday driving, you would not likely see much difference between them, as long as the internals are in good shape. You could feel a difference between the two converters, however.