* Transmission Type: The 1988 truck likely has a relatively older, possibly SM465 or TH400 (depending on the engine and options), while the 1996 Tahoe almost certainly uses a 4L60E (electronic 4-speed automatic). These are completely different designs. Even if both were manual transmissions, the bolt patterns, input shaft lengths, and other dimensions are likely incompatible.
* Transfer Case: The transfer case will also be different and won't mate up.
* Electronic Controls: The 1996 Tahoe's 4L60E is electronically controlled, requiring specific wiring and a computer module. The older truck transmission lacks this.
In short, while some parts *might* be similar, the entire transmission assembly is not interchangeable. You would need a transmission specifically designed for the 1996 Tahoe.
