440-T4 Transmission Valve Body

[WB90GP]

Hi, 

Please guide me in the correct direction if this has already been discussed. Thanks! 

Finding a valve body for the 4 speed 440-T4 (aka 4T60) transmission has proven to be nearly impossible. It appears GM had multiple part numbers and versions listed for different groups of cars and model years prior to the update to the electronically control version of this transmission.

Does anyone know if all model years of the 440-T4 used the same valve body, and if there were any differences between the valve body used in the 1990 Turbo Grand Prix versus the normal 1990 3.1 V6 Grand Prix? 

I found a couple new old stock units on ebay, but none of them are the exact part number listed for my 1990 Grand Prix with the 3.1 V6. However, they appear to look the exact same. 

[Schurkey]

There's a thousand things that can be changed inside a valve body.  Even if the main casting is the same, the valves, the springs, check-balls, and more can be different.  That affects the shift calibration for various vehicles.

I would talk to a local transmission shop.  I bet you can find a suitable core there...and maybe cram a Transgo shift kit into the thing.

[WB90GP]

Ah, that makes sense. Thank you for the input and will definitely see what I can find. @Schurkey