Chevy Astro and GMC Safari Forum banner

Transmission leak- through dipstick tube?

5K views 23 replies 9 participants last post by  Mmusicman 
#1 ·
We had the transmission rebuilt on our '95 a few weeks ago. Today I smelled something burning and found a significant amount of transmission fluid on the right side of the engine! It coated the wiring harness behind the alternator and flowed onto the exhaust manifold, frame, and cross member.

The only thing in that area that would contain transmission fluid is the dipstick tube.

I phoned the shop that rebuilt it and the guy said he doubted it was the tube leaking because no fluid flows through it. He had me check the lines to the transmission and they seem fine (plus they're not even in the main area of the expelled fluid). He said the only reason the tube would overflow is because the vent was clogged. He described where the vent was and what to look for.

He said bring it by on Monday. (I hesitate because of the amount of fluid coming out!) I told him I would pull the doghouse to get a better look.

With the doghouse out i confirmed the transmission lines seemed fine. Also, the vacuum tube from the vent was intact and connected. I removed the tubing to to be sure it wasn't clogged.

The only thing I see is on the dipstick tube is a group of 3 spots along the side of the tube about halfway along, just above where it begins to be more horizontal. They resemble where a bracket may have been spot welded but is no longer (pretty sure there never was a bracket there, but..). One of these spots is actually a small hole!

So, my questions for the hive mind here are:

1) Is it normal for a hole to be at this point? (I'm assuming "no" but have to ask.)
2) Would a hole at this point expel fluid while driving? No fluid comes out at idle.

Any help will be greatly appreciated!
 
See less See more
#3 ·
If your transmission shop installed the front pump gasket wrong,or their cleaning procedures blocked a passageway,the pressure will push fluid up the fill tube,even worse if there is a hole in the fill tube.Not an uncommon problem.
 
#4 ·
I did see another post suggesting tape. But no fluid has been added since rebuild. And I'm talking significant fluid all over the side of the engine. Makes little sense but it makes quite a mess.
 
#5 ·
MechBob said:
If your transmission shop installed the front pump gasket wrong,or their cleaning procedures blocked a passageway,the pressure will push fluid up the fill tube,even worse if there is a hole in the fill tube.Not an uncommon problem.
Interesting. But its been working fine for several weeks. If it was assembled wrong would the symptoms wait this long?
Here's a photo of some of the mess. (Tried to add it earlier, learning to use this MacBook, long curve.)
 

Attachments

#7 ·
So consensus seems to be tape it up. Might go a step further, hose clamp around a piece of rubber. Works for plumbing emergencies in the house. :D
 
#10 ·
Clean the tube and tape it as suggested, JB Weld or whatever you have handy.
Then clean the area a bit, that will let you see if there are other problems or not.
Use paper towels, degreaser or whatever is laying around.
If it gets dirty after plugging the hole & cleaning the area you'll know something is up.
I'm no mechanic, but I would limit driving it until you know if it is a bigger problem.
And if you have to drive, check the Transmission level daily or when you reach your destinations.
You have to shift it to all the gears with engine running before checking the level.
 
#11 ·
Thanks all!
Reassuring to hear others have experienced this, and that it isn't necessarily a big problem. (Of course, the transmission is still under warranty so even if it is big it should be covered.)
I plan to work on it later today and will follow up with results.
 
#12 ·
Yep, super common for the dipstick tube to get damaged where the support brackets are/were attached. I split a piece of hose and used a hose clamp for the last one.
 
#13 ·
AstroWill said:
Yep, super common for the dipstick tube to get damaged where the support brackets are/were attached. I split a piece of hose and used a hose clamp for the last one.
Right. I just have trouble envisioning where the bracket was. Doesn't seem to be near to anything it could have attached to, and replacements (even those called original GM) don't have a bracket midway. Maybe it does more harm than good and newer design leaves it off. And with the plenum taken off multiple times by different mechanics hard to guess when the bracket could have gone bye bye. But this is the most likely cause of the marks and hole, so I'm not going to overthink it. Agree hose piece and clamp should be a solid fix.
Thanks!
 
#14 ·
OK, here's the update and it ain't pretty.

Assuming transmission fluid was low (none showing on dipstick on Friday), I started by adding 1/2 quart.

Started it up and did an initial level check - fluid way up the dipstick. Figuring it was left in the tube when I added fluid, I checked a couple more time - still way high! Then I remembered years ago when we were out of town the radiator reservoir overflowed because the radiator had failed, letting transmission fluid into the radiator (and vise versa). Looked in the reservoir, and yup - filled with red fluid.

Obviously the current radiator failed in the same manner. Shoot! Bad situation for a new transmission.

So I drained the transmission (no sense letting contaminated fluid stay in there any longer than necessary) and the radiator. The transmission fluid actually didn't look as terrible as I imagined it would - looked slightly purple in the drain pan rather than bright red, but still looked, smelled, and felt like transmission fluid. Coolant from the radiator had transmission fluid floating on top of it, but most of it was green.

I plan to refill the transmission with fresh fluid and replace the radiator. Then have the transmission shop replace the fluid (a second time including what I'm planning to do) and filter since I'm not draining the torque converter and I want to get as much contaminated fluid out of the transmission as possible.

When this happened many years ago, we were forced to drive nearly 50 miles from where I noticed the problem before we reached a place where I could replace the radiator. Then another 44 miles to get the transmission fluid changed. It was of course a death sentence for that transmission, but it actually went 2 more years before it died!

I'm hoping for similar results in this situation. Maybe better since the van wasn't driven with mixed fluids nearly as far as before and because the transmission is basically brand new.

Sorry to post such a sad story. Maybe it needs to be moved to "Cooling System". Or perhaps not all that sad - with a new radiator, transmission service, and fluids it should be around $300 to undo most of this.

If anyone has advise on a radiator that will hold up better, or maybe a strategy for helping the transmission survive this better, I look forward to hearing from you.

Thanks everyone!
 
#15 ·
Oh no, hope you caught it quick enough that it only did slight damage.

The biggest thing is maintenance on them, changing the fluids on time. Antifreeze has corrosion inhibitors in it that break down over time and so changing it at the required intervals really helps keep your cooling system in good shape.

Stock sized radiators can be had pretty cheap, ~$70 shipped and up to whatever you want to spend. I replaced mine with a thicker version all aluminum radiator and it fit and works perfectly(came from ebay).
 
#16 ·
AstroWill:
Thanks! Let's hope so!
Truth is the cooling system WAS neglected for a time, radiator got clogged and was replaced at that time. Its less than 2 years old! Probably made in China.
Only other thing I can possibly think of is it got really cold (as low as 9 degrees) here a couple weeks ago and the van wasn't dug out of the snow until it got warmer. Pretty sure the anti-freeze was more than enough to protect it, no other coolant leak that I can tell. Chalk it up to Chinese crap radiator.
 
#17 ·
If it was fine before a big freeze and not fine after a big freeze that definitely would make me think that it froze. 9 degrees is pretty darn cold, but I'm allergic to cold ;)
I'm sure 99+% of radiators are made overseas, could have gotten a bad one, who knows. Heck even 'made in usa' doesn't mean that it's made here anymore. "We put the cap on it and put it in a box, so now it's 'made in usa'".
I would use a $1 tester from walmart to test the strength of your coolant mixture.
 
#18 ·
AstroWill said:
If it was fine before a big freeze and not fine after a big freeze that definitely would make me think that it froze. 9 degrees is pretty darn cold, but I'm allergic to cold ;)
I'm sure 99+% of radiators are made overseas, could have gotten a bad one, who knows. Heck even 'made in usa' doesn't mean that it's made here anymore. "We put the cap on it and put it in a box, so now it's 'made in usa'".
I would use a $1 tester from walmart to test the strength of your coolant mixture.
I do have an antifreeze tester. Didn't check our cars before the cold snap, but same in there as last winter. Guess I could test what I drained out, but could get my tester messy. Might get that $1 tester you mentioned.

But I would think if it got cold enough to crack the metal on the transmission cooler it would have cracked a plastic tank. That's my theory anyway.

Good news is I found the order where I got the radiator from Rock Auto and it has a "lifetime warranty" so hopefully all I'll have to pay is shipping (full shipping on the new part and half shipping on returning the old part). Plus tax. $24.55 total for the radiator. Should bring my total out of pocket closer to $200 depending on what the shop charges to service the transmission.
 
#19 ·
95AstroLT said:
I do have an antifreeze tester. Didn't check our cars before the cold snap, but same in there as last winter. Guess I could test what I drained out, but could get my tester messy. Might get that $1 tester you mentioned.
Definitely worth the $1, or actually $1.76 for two because they changed the minimum required to two. https://www.walmart.com/ip/Chaslyn-Smal ... r/16927981
Recently worked on a vehicle that had only 1 ball float, 20°f is just not enough.
 
#20 ·
Agree with Will 95% on the radiator stuff. You just never know about the quality. But, you do not need a frozen liquid to cause a problem. The colder the weather, the more metals,rubbers,plastics and fluids contract. And,if any of them have already been weakened,bigger chance for a failure.I prefer never to drive my plow truck,in anything -35 below or more,steel breaks much easier. Also, there is the long debated question, do metals respond to wind chill? Well,I believe probably not,but when that metal is layered with something else, such as coolant, a whole different story. Being a mech. most of my life, I have only seen maybe 10 cases of rad./transmission fluid cross contamination.
 
#21 · (Edited)
Update: Replaced failed radiator, OSC brand from Rock Auto. This was what, last May? Tried to get replacement through Rock but they sent me a bent one! Did get a refund, though (I think - their system is wonkey.). Did wind up getting same brand when I went through local radiator shop. Oh well, maybe it was a fluke.
Drained transmission fluid, refilled with new filter. Drove directly to transmission shop for them to check it out and change fluid and filter again. They said it looked fine, won't even affect warranty! Whew!!
Fast forward to today - same thing - transmission fluid in radiator. Grrrr... Hopefully I caught it in time again. (Checked coolant over the week-end, seemed fine then.)
People sometimes ask what brand radiator to get, I'd say STAY AWAY FROM OSC!! Two in a row, failed same way.
I'm looking to get the same brand radiator I put in our Safari in 2016 - Lynol. Bought it through same local radiator shop. May have to go back to them, Lynol's website says "Please sign in to buy this product. " but has no provision to set up an account. Messaged them, may just go to the radiator shop on Monday.
Never had a radiator fail like this on any car, now we've had it 3 times on this poor Astro!
 
#22 ·
Just to update this horror show - it gets worse! (But hopefully OK now.)
Ended up getting an all aluminum radiator from Rock Auto hoping for better durability. Disappointed to see it, too, was made in China. Anyway, put it in, changed transmission fluid (twice). Everything seemed OK except for a kind of whining sound from the transmission in park of neutral, most noticeable when cold.
Fast forward to late April. Van running great - even commented so to my daughter riding with me that it seemed to like the warm weather (90 degree day). Then it begins jerking and transmission very erratic. Stopped, checked fluid (fine). Got back on the road, seemed better for about 1.5 miles then almost lost all power transfer. Limped to the parking lot where my daughter works. Barely made it. Had to push it backwards into a space. No forward, no reverse. Called my wife to pick us up.
After waiting a while, out of boredom tried it again - had forward and reverse! Anyway, left it there and tried a short (< 1 mile) road test the next morning. Seemed fine. What the...??
Waited until that evening with lighter traffic to drive it 3 miles home. Started out fine, made all the red lights fortunately, but almost 1/2 mile from home transmission began slipping and got worse very quickly. Barley made it home.
Thinking transmission was overheated I went underneath with a infrared thermometer. Transmission was basically ambient temperature (58 degrees). What the...???
Drove to the transmission shop (in another vehicle, obviously) and described what was going on. They said it was probably the torque converter failing.
Had it towed there, turned out it probably was the torque converter but transmission rebuild was by then 6 months out of warranty. They recommended another rebuild due to the coolant contamination. Torque converter supplier probably would deny any warranty because of evidence of coolant in the fluid. Transmission shop offered an external cooler at no charge - so glad to have that now - NO chance of mixing coolant and transmission fluid!
So two radiator failures and two transmission rebuilds in 2 years. UGH! This on a vehicle with over 300K miles. Maybe I'm crazy, but only alternative at each step was junking the van (which is like admitting failure) and buying something else. Something else wouldn't cost much less and no guarantee of trouble free $2000 - $4000 vehicle.
So running pretty good now. Can't believe the engine has gone this far with so little trouble - haven't had SBC engines, just our (2) 3/4 SBC 4.3s. Seem to be incredibly durable. Starts instantly, runs cool, good oil pressure, no oil used between 3,000 mile changes, no smoke.
Might as well see how far it will go.
 
  • Like
Reactions: Rustbelt_mVan
#23 ·
My experience with rebuilt transmissions with a number of vehicles is that they do not last long.
Unless you have someone like that did thread just recently on a rebuild.
That person spent a lot more time on it than an average transmission shop.
Even then they had a defective part that need to be changed.
Recently I found that getting a low mile transmission from scrape yard is way more reliable and cheaper.
I have changed my wife's PT cruiser with one and runs great still after a few years and my 2002 AWD is running great to after changing one from scrape yard a few years ago too.
Just keep up with changing the tranny oil filter and oil. Also keep it from overheating.
 
#24 ·
When my 2000 lost suddenly lost forward drive (while shifting) a couple years back.. I limped to nearest parking lot. I suddenly had no forward or reverse. When I shut it down and started up again, suddenly it was good. I drove a couple more miles, then exact trouble happened again (after 1>2 shift).. and same solution. Shut it down, started it up, drove it home.

I dumped some "TransTune" in it the next day and problem seemed immediately solved.
I've had excellent results with this product in the past on several different transmissions.
I attributed the trouble to a stuck (or sticking) valve, which was most likely the case.
Fluid looked good.. I drove for some time more.

But it was only a brandaid (a temporary fix) covering up a bigger problem.

The product needed to be drained, and I figured I better change the filter as well.
When I dropped the pan, I was presented with the bad news...
There was all kinds of debris in the bottom of the pan (previous time it was spotless)
The debris is what was likely cause the sticking valves as well.
This transmission was DONE! It was in it's final moments of life.

Coincidentally I was supposed to drive out of state the next morning. I found a highly respected local rebuilder near my house who asked how fast I could get it to him. I headed right over. Later that day he informed me of the internal damages, including some broken gears, and was surprised I was even able to drive it in. He would need to get a few parts. In retrospect, I believe I damaged this stock original trans on a difficult job site some time previous. None the less it was now at about 230K which I still consider pretty amazing.

I get another call next day (expecting the worse) and he shocked me by informing me it was done and ready to go! My trip was only delayed by one day. The trans has since been fantastic (on it's new 2nd life now), several years later, numerous out of state trips, tens of thousands of miles later. I was fortunate! I have an honest and rock solid builder.

That's my story... good luck

PS: The only time in my life I ever had trans fluid come out the stick is when it was under severe immediate distress and temporarily overheated.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top