Early/Late 904 measurement?

[halfafish]

I have a slant 904 trans and TC that came to me in a parts lot. I'm aware there were differences in the TC between early and late versions - I think it has to do with the snout size? Anyway, I'm trying to determine which one I have. Does anyone know where to measure for this difference, and which one is which?

TIA - I plowed through several FSM's last night to no avail.

 

[Professor Fate]

Judging by an adapter ring I've got in my drawer, the nose on the late torque convertor is ~1.8", and the early is ~1.55".
If it's an early one, and it has a slip yoke output, it is a '66-'67. If it has a ball & trunnion output plate (and the small speedometer drive) it is a '65 and earlier.
The input shaft spline count is also different between early and late, 18 vs 27 splines.

 

[Kern Dog]

There were additional changes later as well.
I don't know exactly when, but the 904 after what....1980 or so?....It was revised with a hydraulic lockup converter that had no external wiring, it activated completely hydraulically. The low gear 1st and 2nd gear came along around that time too, I recall.
I have a 904 based 999 trans from a mid 80s Chrysler Fifth Avenue. It was Chryslers back door attempt to get by until the overdrive transmissions could be developed and released. They ran super tall axle ratios in the vehicles fitted with the 999 transmissions, the Fifth Avenue cars having a super tall 2.21 ratio! The deeper 1st gear made it feel like you at least had a diff gear around 2.50 which is still weak!

 

[Vaanth]

I have a slant 904 trans and TC that came to me in a parts lot. I'm aware there were differences in the TC between early and late versions - I think it has to do with the snout size? Anyway, I'm trying to determine which one I have. Does anyone know where to measure for this difference, and which one is which?

TIA - I plowed through several FSM's last night to no avail.

The change in the A904 Torqueflite input shaft and the corresponding converter hub size change occurred for the 1968 model year. The input shaft size, reaction shaft size, and related parts were changed for more load capacity.

The input shaft spline counts changed as follows:

• The 1960 - 1967 A904 Torqueflite input shaft has 18 splines.
• The 1968 - 1977 A904 Torqueflite input shaft has 27 splines.

The corresponding torque converter hub sizes are as follows:

• The 1960 - 1967 A904 Torqueflite torque converter hub measures 1.550 inch.
• The 1968 - 2002 A904 Torqueflite torque converter hub measures 1.810 inch.

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For more general information on the spline counts for A904 and A727 Torqueflite transmissions, refer to the following:

A904, A998, A999, A500

• The 1960 - 1967 A904 Torqueflite input shaft has 18 splines.
• The 1968 - 1977 A904 Torqueflite input shaft has 27 splines.
• The 1978 - ~2002 A904, including A998 and A999, Torqueflite with lockup converter input shaft has 26 splines plus a smooth machined area without splines at the nose of the shaft.
• The A500 Torqueflite with overdrive, that replaced the A904, input shaft also has 26 splines.

A727, A518

• The 1962 - 1966 A727 Torqueflite input shaft has 19 splines.
• The 1967 - 1977 A727 Torqueflite and 1978 - 1991 A727 Torqueflite with non-lockup converter input shaft has 24 splines.
• The 1978 - 1990 A727 Torqueflite with lockup converter input shaft has 23 splines plus a smooth machined area without splines at the nose of the shaft.
• The A518 Torqueflite with overdrive, that replaced the A727, input shaft also has 23 splines.

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