Transmission Dipstick Tube Seal difficulties

TequilaWarrior

Original poster
Member
Dec 5, 2011
574
Central Pennsylvania
TL:biggrin:R, just a question at the bottom.

After replacing my exhaust manifold, exhaust manifold gasket, firering, valve cover gasket, intake gasket, and throttlebody gasket I was certain that my days of finding puddles of fluids under the car were over.... alas, they were not. Copious fluids began to present themselves overnight.

After much head scratching and multiple crawlings under the car, I figured out it was the transmission dipstick tube seal. I had pulled the dipstick tube free to get better access to the exhaust manifold and I was never quite certain that I got it to reseat. Well, it reseated, torn to shreds, but reseated. I could barely get my fingertips to feel it and from what I could feel I was panicked that the dipstick tube had actually also rusted through at the tranny.

Upon removal of the dipstick tube I found it was intact - rusted a little, but intact. The seal, however, was completely shredded. Sourcing one proved to be an exercise in frustration and futility. It's a $2 part.... that no one carries. RockAuto could've got me one... next week. My local parts store that's usually 6 times more expensive than dealer pricing got me one the next day and for only 3 times everyone else's price. Oddly, they only charged $10 a quart for DexVI. I think these bottles were filled from the very first batch of DexVI ever made.

The installation of this absolutely ridiculous little part was about as clear to me as the fluid I got out of my last differential fluid change.... in other words it wasn't clear to me at all how to install this stupid thing.

Examining this stupid seal revealed that it has parallel rings cast into it on the portion that goes down into the transmission. The top was funnel shaped. It was a firm, but not alarmingly tight, fit to the tube end. BUT! I also noticed a kind of "recessed" ring on the inside of the seal itself right below the tapered "funnel" shaped upper portion. It seemed to me that this "recess" is where the ridge around the outside of the dipstick tube should be when the seal is properly installed. SO I did just that. Installed the seal on the tube making sure the ridge indexed into the recess inside the seal. I then tried to install the tube. With much valiant effort supplied by my 9 year old daughter I got it to go in - me under the car, her standing on a cement block pushing the tube. Giving it a good eyeing however, revealed that the seal pushed up the tube providing no sealing what so ever at the tranny. Remove, rinse, repeat... er... So I tried again. It occurred to me that placing the seal onto the tapered portion of the tube so that the ridge sat at the very top of the funnel might cause the seal to push further up so that the ridge is indexed into the recess as the seal drops down in.... nope. Seal pushes right up. Final attempt: installed the seal into the transmission and fished the tube into the top of it and pushed it in. And pushed some more. And pushed some more. No matter what I could not get that ridge down past the funnel shaped top. Coincidentally, at this point the mounting hole lined up to it's original location perfectly. I relented and decided "screw it" it's close enough. At least it should be sealed enough to drive until I hear from someone who actually knows whether this is wrong or not.

I managed to get a picture of the seal/tube as it sits, mounting nut installed above the exhaust manifold. It's hard to make out, but the seal is fully seated into the transmission and the ridge on the tube is sitting at the top of the seal. You can barely make out the ridge in the picture. Should that be out and visible or down and inside the recess in the seal?
20200617_192156 (Large).jpg

Oh, and DexVI will melt spray paint that hasn't fully cured.... just a FYI.
The detergents in DexVI also melt grease and turns it into a goo that appears to be a cross between ink and slime. The whole passenger underside of the car was covered in this damn goo.
 
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Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
I'm pretty sure that the ridge sits on top of the seal, just like yours is. All the times I've had to deal with that dipstick, I did it with the seal in the tranny and putting the tube in. No issues that I can recall however I don't think I've ever had to deal with a new seal.
 

mrrsm

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Oct 22, 2015
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Tampa Bay Area
Yup. And while it might seem that aftermarket seals would work in this situation... if they have too extreme of bevel inside, just below that "Square Shoulder" in the rubber molding... then the Black Steel Transmission Dipstick Guide Tube will keep trying to pop right back out unless you can jam it in correcetly AND slide the Hold In Bracket in place.

From a similar experience during my R&R of the '02 TB 4L60E ... I tried using a cut off length of a rounded off Squeegee Handle to help push the seal back in place. This was like trying to Pat your Head and Rub your Stomach in Circles at the same time.

Amazon carries this ACDelco OEM Grommet-Seal Part #1259475 for $5.00 with Free S&H:


4L60EDIPSTICKSEAL.jpg4L60EDIPSTICKSEALA.jpg
 

TequilaWarrior

Original poster
Member
Dec 5, 2011
574
Central Pennsylvania
Thanks for the replies.
I'm virtually certain the part I received is 100% genuine ACDelco OEM. I compared it to the remnants of the seal I removed and they're a perfect match.
For good measure, I bent the mounting bracket slightly to provide a little downward pressure on the grommet.
I attempted to pressure wash the underside of the car - at least the parts I could reach at the self-serve car wash - to see if I can remove that black goo so I can keep a close eye out for any dripping transmission fluid. For good measure, I bought 3 bottles of the "good stuff" from my local parts guy - at $10/bottle - just in case I need to add any.
 

mrrsm

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Oct 22, 2015
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Tampa Bay Area
It is rare... but there IS a second location where the ATF can leak out of an over-filled 4L60E that is cold with the Engine Off. A leak around the inner seal of the Solenoid Harness inside this port into the upper body of the AT Case can also interfere with the operation of the 20 Pin External Harness Connector Pins buried inside of the Light Green Inner Plug.

An inspection with a small mirror and flashlight will reveal any issue there. Check around underneath the In and Out Transmission Cooler Lines for their Silicone Seals failing as well from signs of dripping fluid on the lower case wall as well.

That harness port is located roughly on the same plane as the Transmission Fluid Filler Neck Hollow Cavity. As such, if the SUV-Truck is parked on a downward incline and leaking, it could give the impression that the fluid is leaking from the filler port as illustrated in these images:

4L60E20PINHARNESSCONNECTOR.jpg4L60E20PINHARNESSCONNECTOR1.jpg
 
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