Will a 1991 Chevy 1500 transmission fit into 1998 1500?

It's unlikely a 1991 Chevy 1500 transmission will fit a 1998 Chevy 1500 without significant modifications, and it's probably not advisable. While both are Chevy 1500s, GM made significant changes to their trucks and transmissions over those seven years. The bolt patterns, bellhousing, input shaft, output shaft, and even the electronic controls (if applicable) are likely different. You'd be facing major compatibility issues.

Don't assume compatibility based solely on the "1500" designation. You need to identify the specific transmission in each truck (e.g., 700R4, 4L60E, etc.) and compare their specifications. Even if the transmission *type* is the same, there are often subtle differences within those types across model years that prevent direct swaps.

To know for sure, you need to:

* Identify the specific transmission in both trucks: Check the casting number on the transmission itself.

* Compare those numbers: Look up the specifications for each transmission to see if they are truly compatible. Online resources like transmission parts suppliers' websites or forums dedicated to GM trucks can be helpful.

Trying to force an incompatible transmission will likely lead to more extensive and costly repairs later. It's best to source a transmission specifically designed for your 1998 Chevy 1500.