Bubbles on Trans Dipstick

[Pat M.]

Hey guys. I decided to check my Trans Fluid today after a highway drive, at idle on a level surface.

When I pulled out the dipstick I noticed air bubbles on it.

Is that bad?

The level was fine and it's a 4000 mile fill of M1 fluid in a GM DEX III tranny.

Any insight would be helpful. Thanks.

 

[Camu Mahubah]

Bubbles... I do know that air doesn't lubricate... you are running a syn and you have bubbles... I hope someone chimes in... Maybe the syn cleaned a false seal and allowed air to be sucked in...

I want to recommend idiling the car and maybe some short city driving to see if bubbles are still prescent after tranny is up to operating temp... that is tommorrow after you have allowed time for tranny fluid to so to say release it's gas... I could be wrong but don't worry too much until someone who really knows trannies says to worry...

 

[unDummy]

As long as level is correct, bubbles are meaningless, and overhyped on the web.

 

[westwind999]

I had a GM transmission that had bubbles too. I asked a reputable transmission shop about it and they said they all do it and it doesn't seem to hurt anything.

 

[BullyT]

I hate to be the bearer of bad news, but years ago my Chevy Lumina always had bubbles on the tranny dipstick when I checked the fluid level...it made it difficult to get an accurate reading. Tranny failed at 78,000km (about 48,000 miles) and required a complete rebuild. No other vehicle I have owned has had bubbles on the dipstick so I don't believe it is "normal".

 

[Syntec-Man]

bubbles are formed buy aeration, the oil foams and bubbles are produce. Is there too much fluid in that tranny. trannys hate overfills man

 

[Pat M.]

Hum. No it's not overfilled, it's about half way in the "normal" crosshatches.

The trans shifts alright, punches slightly from 1 - 2 but I think it's more my foot that does it.

I was just curious, whatever happens will happen to her, best I can do is insure quality fluid and correct level. I'll check it again in some other areas to ensure I was indeed on level and report back (tomorrow seeing as how it's dark here)

 

[pp_rp]

Quote:

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As long as level is correct, bubbles are meaningless, and overhyped on the web.

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Well maybe? Bubbles decrease lubrication and increase heat. Depends how severe the bubbles are.

 

[PT1]

Is your filter all the way on? Sounds like you may have a loose filter o-ring seal. If the trans is shiftin funny at all you may want to drop the pan and get a look at the filter seal. There is another post here somewhere with a similar situation. Also, check all your lines and filler tube for any possible leaks. I would put a wrench to all the lines to make certain you aren't sucking in air anywhere. And look for any wet seals.

 

[oilboy123]

Maybe fill till it is at the max fill just to verify it is not foaming up to the halfway mark? Just a thought before tearing into it.

I would be kinda concerned.........

 

[unDummy]

He didn't see bubbles IN his fluid. Bubbles float.
As you pull the dipstick out, some bubbles from the top of the fluid will stick to the dipstick. Some bubbles might be formed simply by the dipstick's travel through its tube.
For example, take a straw and blow some bubbles into your cup of milk. Draw in some milk through your straw. Suck any bubbles from the top with the straw at the bottom of your glass? Pull the straw out and some bubbles will stick to its sides.
So, where is the ATF pump's pickup in relation to those bubbles?

Like I said, overhyped internet garbage.

If your fluid is foaming, you don't have a bubbles problem. You have a fluid type, a fluid condition, a snake oil additive issue, mechanical problems, or hopefully a simple level issue.

If the fluid is at the correct level, doesn't have any contamination, and isn't wasted or used beyond its useful life, the bubbles you see on your dipstick are NOT a problem.

 

[gomes512]

I would think if there was an aeration issue then the fluid would be a lighter color. It's improbably just what unDummy said, bubbles on top sticking to the stick. My Jeep does the same with ATF+4 in the tranny. Some bubbles but otherwise clear red fluid. That's been like that for the past 130K and the tranny shifts fine.

 

[Hermann]

My past experience is the vehicles that you check while at idle, have had air bubbles on the stick. On the Honda which is checked hot with the motor off, I have seen no bubbles.

 

[The Critic]

My fully filled GM TAAT transmission will have some bubbles too when its filled to the MAX line. Don't worry about it.

 

[JHZR2]

on all of our ATs, a GM, Chrysler, Toyota, and two MBs, they all show bubbles. On all of them, reading ATF level is the hardest measurement to do, because it is never repeatable, or consistent.

It seems normal, at least enough for us to get multiple ATs to over 200k miles without rebuilds or any shift quality issues...

JMH