Confused about air in clutch fluid line

Maintenance/Repairs
1

2000 Pontiac Trans Am. The other day I had to get my car towed because it wouldn’t go into gear, I figured there was air in the clutch fluid line and when I peeked under the hood the fluid was very low and black. I added some and used a mityvac to bleed it (you have to drop the transmission to get to the slave cylinder in a T56, pain in the ass) so now it drives. I took it for a test run and it was going fine, I did a pretty hard pull and once I got to 5th gear the pedal went limp again, but after I let it sit for a second it became firm. My fluid was definitely lower than before, but I couldn’t find any leaks. I added some fluid, tested it again, and I had no issues with the pedal. Is it 100% guaranteed that when the pedal went numb and the fluid was low, some fluid leaked out? Or is it possible that there was air in the system that got pushed out, causing the fluid to appear lower? I’m no physics major, please help me out here.

2

Go under the dash, drivers side, and pull the carpet away from the firewall to see if hydraulic fluid is leaking from the clutch master cylinder rear seal.

Tester

3

I checked that, it’s dry as a bone. I’m almost sure it’s the slave cylinder, just because there’s nothing else it really could be. I think the leaked brake fluid has just pooled up in the transmission since there’s nowhere for it to go. One of the seals is a little wet but I’m not sure it’s brake fluid.

4

There’s no such thing as a 2000 PontiacTrans AM

https://www.rockauto.com/en/catalog/pontiac

Tester

5

pontiac firebird, trans am trim

6

Okay. I see.

The slave cylinder is inside the bell housing.

The slave may be leaking. Because clutch dust can absorb a lot of fluid.

But the only way to know is, remove the transmission.

Tester

7

Right, I figured that’s what it is. But what I want to know, do you think it’s possible when I tested it and the pedal went soft and the fluid level dropped that I pushed some air out of the lines? Or is it probably just more leaking? I tested it a second time with no pedal issues or fluid level drop.

8

Fluid level drop points to an external leak.

Tester

9

Yes, there is:

4th Gen F body built from 1993 to 2002.

Reviewed by Motor Trend