Mine seemed to be related to the 235/60R18 goodyear forteza tires. When I changed to 16's, it went away.
There is also some talk of a programmed breaking in period for the torque converter clutch. Supposedly this manifests itself as a shudder for the first few thousand miles as the TCC is allowed to slip momentarily in order to "lap" the mating surfaces together.
91 YJ Sahara, 4.0L, AX-15/NP231, D30/D35@3.07
12 Cherokee 4x4,3.7L,42RLE/MP1522, D30Memail@example.com
"Non Vi Sed, Arte"