2006 Tacoma - Manual Transmission new VSS

My son has a 2006 manual Toyota Tacoma (4 cylinder), and we were trying to replace the transmission speed sensor. Easily able to remove the one on there, but the new one won't go all the way in...it seems to be too tight of a fit. We tried putting some oil/fluid on it, but to no avail. It's a cramped space so there really wasn't room to use a mallet to gently try to tap it in.

The part was a Dorman brand ordered from Rock Auto. Could the part just be junk? I intentionally didn't order the cheapest part. Any thoughts on how to get it in place?

He has the P0500 code and the speedometer is intermittently working. It does have a small lift and non-stock tires (when we purchased used)