Car shakes & halts in reverse

Hey, CarTalk folks,

This is probably an obvious problem but I need help. I need an oil change and, probably unrelated, I couldn’t get my car into Reverse on Wednesday night. I managed to pull it into the driveway and then got busy with Thanksgiving stuff.

Today I went through the manual and thought I might be out of transaxle fluid. So, following the instructions, I ran the car in idle for 15 minutes and checked and, yes, it is definitely low. But afterwards (car still running), I tried shifting gears and it went smoothly into all of the them except Reverse where the bottom of the car just shuddered.

Is this a problem that can be solved by adding or changing transaxle fluid or something more serious? I should say that I normally keep the car well-maintained but I’m unemployed and have had to cut back on any expense that wasn’t absolutely essential.

I’m also concerned about even driving the car to a repair shop, whether I’ll be doing further damage & should get it towed. Drive seemed to work fine, it was just Reverse that made it feel like the bottom of the car was falling on to the ground.

Any advice would be helpful. Thanks in advance.

I should say that it’s an automatic transmission on a 1996 Saturn. It was given an overhaul/tune-up when I bought it in 2005 & has pretty low mileage (85,000). Mostly a drive around town car.