: Bubbles on trans fluid dipstick bad?

01-04-10, 09:50 PM
Hello all I was wondering if you could help me out. I have 120k on my '95 Aurora and i just checked the trans fluid and it took about 1 quart to bring it back to the top 'HOT' crosshatch. I noticed a fluid leak on my garage floor and it was trans fluid, dripping a drop or 2 here and there every day. And i noticed there are bubbles on the dipstick. They go about 1/4 of the way up the stick. Small little bubbles mixed in with the fluid. I am pretty sure i've seen that before...so are they really bad? Now that it has full fluid will any air thats in the system work itself out over time?

I am having my mechanic do front struts next week, is there anything i can have him look for trans-wise for leaks? oil cooler lines, trans lines or something?

I had the fluid changed (not flushed) about 30k ago with Dex IV. It's been running great ever since. Still ran great even with low fluid, but i decided to check it and im glad i did. Thanks :stirpot:

01-05-10, 08:55 AM
Bubbles are not normally something to worry about - that transmission is a dry sump unit so there's quite a bit of pumping and aeration going on in there. The normal level, with the engine running in P, warm, is halfway up the dipstick hashmark. (There should be NO fluid on the stick with then engine OFF.) Any more (overfill) and really hot oil, such as in towing or summer stop & go, will tend to blow out the vent tube which is a metal capped affair clipped near the throttle cable brackets. The transmission operates with atmospheric pressure on the oil sump - it's vented to atmosphere - so there's always air flying around in there along with oil vapor. (FWIW the transmission temp sensor turns fans to FAST at 305 degrees - yep, 305 degrees.)