It seems that I've found another error in the S32DS v1.2 MPC5746R.h.
Referring to table 54-19 in the MPC5746RRM.pdf, the DMATXDE register is often at offset 0x58. The supplied header file always has it at offset 0x98. This results in a Machine Exception (IVOR1) when you try to write it.
I found this on Linflex 2.
LINFlexD_2_DMATXE = 0;
1048ece: 70 ff e7 e9 e_lis r7,65513
1048ed2: 48 06 se_li r6,0
1048ed4: 54 c7 00 98 e_stw r6,152(r7)
i.e. 152(r7) = FFE90098 which generates an illegal write. It should be FFE90058