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.
74 CJ5, 258, T14a/D20, D30/D44@3.73
12 Cherokee 4x4,3.7L,4RLE/MP1522,D30M/8.25"@3.73,215/85R16 mich LTX A/T2
"Non Vi Sed, Arte"