Interesting.
Edit: So, I went to GMPartsGiant and plugged in 1998 Chevrolet K1500, 1998 Chevrolet K2500, and 1998 Chevrolet K3500. (I used 1998 since GM produced 1/2-ton Silverados (GMT800) in 1999, right?)
The K1500 uses P/N 26100345.
The K2500 uses either a P/N 26100345 or a P/N 26100335. The determining factor is the GVWR. RPO code C6P, which is 8600 lb. GVWR, uses the 26100335. RPO code C5Z, which is 7200 lb. GVWR, uses the 26100345.
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The K3500 uses the 26100335.
If you look on
here, you can see all the parts that differ between the two steering gear boxes. For example, they have a different “rack kit” in each one. Many other parts differ as well. So, yes, I don’t doubt they would each bolt up to the frame, but the performance will differ. I cannot in good faith sell my 3/4-ton steering gear box to someone who has a 1/2-ton unless they state they are looking for a 3/4-ton steering gear box.
Upon a quick review, these are the parts that I observe as being different:
# seal kit, steering gear Pitman shaft
# valve kit, steering gear
# bearing kit, steering gear stub shaft
# plug, steering gear housing
# seal kit, steering gear end plug
# rack kit, steering gear
The valve kit and rack kit almost certainly create a performance difference somehow.