Re: IML: Torque Converter Question (A-727)

While the bolt pattern and case shape remained identical for all aluminum-body 727s, there were many changes. I lifted this from another page. It's a quick reference only, and there are other substantial changes that must be addressed when swapping transmissions -- especially internal vs. external balance for forged and cast crankshafts. Also please do not forget that most of these transmissions are between 25 and 45 years old, and the internals from one will fit inside the case of another.

"A-727 transmissions from their inception until 1966 have 19 splines on the input shaft. Non-lockup 727 transmissions from 1967 onward have 24 splines. Lockup 727 transmissions that debuted in 1978 had 23 splines.

Not all 727 transmissions made after 1978 were lockup; specifically towing package 727 transmissions commonly were non-lockup, and would have the '67-onward 24 spline input shaft. The A-518 overdrive also has 23 splines. The output shaft has 29 splines.

A-904 transmissions from their inception until 1967 have 18 splines in the input shaft. Non-lockup transmissions from 1968 have 27 splines. "

So your mechanic was kind of right but kind of not in details, and absolutely right that you can not use a 1966 transmission and a 1968 converter.

Please see this link for transmission identification based on stamping number on the driver's side just above the oil pan.

http://www.mymopar.com/downloads/transguide.pdf

Happy motoring,

Ken & Tracie <ktjosephson@xxxxxxxxxxxxx> wrote:

I purchased a transmission from Phil Juliano for my '68 Crown. Phil does know his stuff. The transmission was marked 1968 and came with a torque converter.

When we were installing the transmission, a friend's brother, who is a mechanic, was having difficultly getting the torque converter to lock into place on the input shaft. He called in a transmission shop owner he knows. This guy checked it out and claims I have a 1966 transmission with a ninteen spline hub and a 1968 transmission with twenty splines.

Does this sound correct? Even if this is a '66 Tranny, I was under the impression all '65 & up standard duty A-727s for passenger car use used the same spline count.

Comments?