driveshaft modification when lowering? 5.3 and 4l65e

[MMLX89]

Hey Guys-

I have another thread going regarding my recent failure on a truck that I just bought. Short story was that it appears that the rear gear oil was left out when the restoration was done. Rearend failed, locked up and broke the sunshell in the trans.

I have now had the rearend rebuilt, purchased a new trans, and now the shop is saying that the driveshaft is too long. When you guys have done your swaps and then lowered your truck, did it require a shortened driveshaft? I am just trying to filter through possible shop BS to see if this really needs to be done. It drove just fine prior, no vibrations, etc.