1993 Buick Riviera Owner's Manual - Page 231

Automatic Transaxle Fluid When to Check and Change: A good time to check your automatic transaxle fluid level is when the engine oil is changed. Refer to the to Maintenance Schedule to determine when change your fluid. See "Scheduled Maintenance Services" in the Index. How to Check: Because this operation can be little difficult, you may a choose to have this done at a Buick dealership Service Department. If you do it yourself,be sure to follow all the instructions here, or you could get afalse reading on the dipstick.