* Transfer Case: The biggest hurdle is the transfer case. The 2WD Suburban has no transfer case. The 4x4 truck needs one to send power to the front axle. The output shaft of the Turbo 400 is not compatible. You'd need a completely different output shaft and likely a custom adapter to mate it to a transfer case.
* Length: Even if you could overcome the transfer case issue, the length of the transmission case might be different, affecting driveshaft length and potentially interfering with the body or frame.
* Bolt Pattern: While the bolt pattern *might* be the same for the engine to transmission mating surface, it's not guaranteed, and any slight differences would be a major problem.
In short, while both vehicles use a Turbo 400 *type* transmission, the 2WD and 4WD versions are significantly different. It would be far more practical and less expensive to find a used Turbo 400 specifically from a 4x4 vehicle of a similar era. Even then, ensure the transmission's spline count matches your driveshaft and transfer case.
