Trans fluid drops out of the dust cover weep hole? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**IT Cowboy** · 03-08-2026, 08:14 PM

I am still chasing a small leak that is only 1-2 drops a week after driving.

I think I may have narrowed down the source of my small leak. During my last oil change I didn’t add UV dye to the engine oil, but there was still dye in the transmission fluid. I’m seeing some green residue and wetness around the transmission pan. What I don’t understand is how transmission fluid could make its way from the pan area into the dust shield and then drip out of the weep hole. Is there a path where fluid could migrate like that? The flywheel is dry and it isn't slinging fluid and I think if it was the front pump seal it would be a lot more fluid.

**57taskforce** · 03-08-2026, 10:35 PM

Your pump is most likely leaking, the converter is possible but much less likely from my experience any way. It could be leaking when it’s cold and not enough to make a big mess. There’s really no other path for the fluid to get from the pan to the dust cover.

Grounded63 · 03-08-2026, 10:50 PM

Pump to case seal, pump to case bolts, pump to TC seal. Any minor weeping from one of those areas. Will not make it far forward enough to be flung off of the flexplate.

**Steeveedee** · 03-08-2026, 11:08 PM

^ and a couple of drops a week aren't worth the expense. My selector shaft seal leaks enough that I'm going to have to bite the bullet and have it fixed. Arthritis has me quite limited, so I can't do it myself.

**IT Cowboy** · 03-08-2026, 11:24 PM

I think I am going to try a paper towel test and shove some up in there after a drive and cleaning to try to catch the source instead of the fluid leak end destination. I am really hoping it might be the front of the trans pan seal leaking into the dust shield when the fluid drains back into the pan

I might add some high mileage ATF to maybe buy some time and then live with it for now.

**IT Cowboy** · 03-10-2026, 03:57 PM

A complete seal kit installed was quoted to me at $1200 from a local transmission shop.

**57taskforce** · 03-10-2026, 04:24 PM

You might as well rebuild it if you’ve got it out and aren’t 100% sure of its history… just my .02 anyway.

geezer#99 · 03-10-2026, 04:53 PM

Check the vent is clear.

**PbFut** · 03-10-2026, 05:57 PM

Just for reference. Last year a local shop rebuilt my th350 for under 2K including new converter some small upgrades. No race parts. Very happy with results. I removed and installed. If it's out to reseal, may as well go all the way. Happy with my results. Shifts like new. Zero leaks.

72c20customcamper · 03-10-2026, 06:08 PM

Quote:

Originally Posted by IT Cowboy

A complete seal kit installed was quoted to me at $1200 from a local transmission shop.

I had my 350 rebuilt for that with a rebuilt converter I R&R’d the trans not the shop so no labor .

**67 twins** · 03-10-2026, 07:08 PM

Quote:

Originally Posted by 72c20customcamper

I had my 350 rebuilt for that with a rebuilt converter I R&R’d the trans not the shop so no labor .

Same here. I had the one rebuilt in the wife's 72. Cost me $1136. I was originally going to have them do the entire job. They told me they could rebuild the transmission in 3 days, but it would be 6 weeks if they did the R&R. They had it done in two days.

KQQL IT · 03-10-2026, 07:15 PM

A lot of Transmission shops won't warranty your labor or your cooler.

cbeerman · 03-10-2026, 09:19 PM

Check the trans selector shaft. I had a similar problem on my 06 GTO where it would drip a few drops from the inspection cover but everything inside was dry.

**IT Cowboy** · 03-10-2026, 09:33 PM

The source seems to be running down the the inside passenger edge of the dust cover. I need to look at the flywheel closer. I agree if I have it out i might as well have it rebuilt. The shop I had it quoted gives a three year warranty.

**Rust_never_sleeps** · 03-10-2026, 09:43 PM

Quote:

Originally Posted by KQQL IT

A lot of Transmission shops won't warranty your labor or your cooler.

An XJ guy I follow stopped warrantying his rebuilt trannies because people would mangle the cooler lines removing/installing and cook them. Still stands behind the ones he installs

**IT Cowboy** · 03-10-2026, 09:50 PM

Would a new torque converter help it be more responsive or hook up quicker or a new converter with different specs

**57taskforce** · 03-10-2026, 10:19 PM

Quote:

Originally Posted by IT Cowboy

Would a new torque converter help it be more responsive or hook up quicker or a new converter with different specs

Short answer is yes, but there’s a lot of variables there and truly probably not worth pursing unless you go thru the engine, especially the cam and heads to be able to get the most of a higher stall converter. Higher Stall speed will change the driving characteristics quite a bit. They are fun to drive like that though.

72c20customcamper · 03-11-2026, 09:08 AM

Quote:

Originally Posted by KQQL IT

A lot of Transmission shops won't warranty your labor or your cooler.

Mine did , he even gave me a can of the flush they use for the cooler . Only thing I had to do was bring it to his shop afterwards for him to look at the install and test drive . He does a lot of older vehicles . Going to have him rebuild my Studebaker’s Borg-Warner trans not the it’s bad but it starts in 2 nd gear which is factory even though you can manually drop it into first . Just the way they were made . He converts it to a true automatic three speed .

**MikeB** · 03-11-2026, 03:34 PM

Can't believe today's prices. Of course, I'm livin' in the past! But even back in 2015, a friend of mine rebuilt a TH350 I had using about $100 in parts. The trans was out of the truck when I took it to him, and he spent around 2-3 hours going through it. I then added a $50 TransGo kit to the valve body, and bought a reman converter for $60 from TranStar.

I'd guess parts must cost 2x as much now, and labor is $300/hr.

03-08-2026, 08:14 PM	#1
IT Cowboy Senior Member Join Date: Jan 2025 Location: Arizona in a van down by the river Posts: 617	Trans fluid drops out of the dust cover weep hole? I am still chasing a small leak that is only 1-2 drops a week after driving. I think I may have narrowed down the source of my small leak. During my last oil change I didn’t add UV dye to the engine oil, but there was still dye in the transmission fluid. I’m seeing some green residue and wetness around the transmission pan. What I don’t understand is how transmission fluid could make its way from the pan area into the dust shield and then drip out of the weep hole. Is there a path where fluid could migrate like that? The flywheel is dry and it isn't slinging fluid and I think if it was the front pump seal it would be a lot more fluid. __________________ 1972 C10 Custom Deluxe Highlander 402 Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

03-08-2026, 10:35 PM	#2
57taskforce All about them K’s Join Date: Jun 2014 Location: Land of Entrapment Posts: 6,975	Re: Trans fluid drops out of the dust cover weep hole? Your pump is most likely leaking, the converter is possible but much less likely from my experience any way. It could be leaking when it’s cold and not enough to make a big mess. There’s really no other path for the fluid to get from the pan to the dust cover. __________________ Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 35x12.5x20’s

03-08-2026, 10:50 PM	#3
Grounded63 Registered User Join Date: Dec 2016 Location: Canon City, Colorado Posts: 265	Re: Trans fluid drops out of the dust cover weep hole? Pump to case seal, pump to case bolts, pump to TC seal. Any minor weeping from one of those areas. Will not make it far forward enough to be flung off of the flexplate.

03-08-2026, 11:08 PM	#4
Steeveedee Ram-A-Lam-A-Ding-Dong Join Date: Jan 2013 Location: Simi Valley, CA Posts: 11,899	Re: Trans fluid drops out of the dust cover weep hole? ^ and a couple of drops a week aren't worth the expense. My selector shaft seal leaks enough that I'm going to have to bite the bullet and have it fixed. Arthritis has me quite limited, so I can't do it myself. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

03-08-2026, 11:24 PM	#5
IT Cowboy Senior Member Join Date: Jan 2025 Location: Arizona in a van down by the river Posts: 617	Re: Trans fluid drops out of the dust cover weep hole? I think I am going to try a paper towel test and shove some up in there after a drive and cleaning to try to catch the source instead of the fluid leak end destination. I am really hoping it might be the front of the trans pan seal leaking into the dust shield when the fluid drains back into the pan I might add some high mileage ATF to maybe buy some time and then live with it for now. __________________ 1972 C10 Custom Deluxe Highlander 402 Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

03-10-2026, 03:57 PM	#6
IT Cowboy Senior Member Join Date: Jan 2025 Location: Arizona in a van down by the river Posts: 617	Re: Trans fluid drops out of the dust cover weep hole? A complete seal kit installed was quoted to me at $1200 from a local transmission shop. __________________ 1972 C10 Custom Deluxe Highlander 402 Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

03-10-2026, 04:24 PM	#7
57taskforce All about them K’s Join Date: Jun 2014 Location: Land of Entrapment Posts: 6,975	Re: Trans fluid drops out of the dust cover weep hole? You might as well rebuild it if you’ve got it out and aren’t 100% sure of its history… just my .02 anyway. __________________ Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 35x12.5x20’s

03-10-2026, 04:53 PM	#8
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,973	Re: Trans fluid drops out of the dust cover weep hole? Check the vent is clear.

03-10-2026, 05:57 PM	#9
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 1,024	Re: Trans fluid drops out of the dust cover weep hole? Just for reference. Last year a local shop rebuilt my th350 for under 2K including new converter some small upgrades. No race parts. Very happy with results. I removed and installed. If it's out to reseal, may as well go all the way. Happy with my results. Shifts like new. Zero leaks.

03-10-2026, 07:15 PM	#12
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,447	Re: Trans fluid drops out of the dust cover weep hole? A lot of Transmission shops won't warranty your labor or your cooler. __________________ " That didnt make it any newer " " Dont antique the equipment "

03-10-2026, 09:19 PM	#13
cbeerman Registered User Join Date: Jan 2016 Location: NJ Posts: 455	Re: Trans fluid drops out of the dust cover weep hole? Check the trans selector shaft. I had a similar problem on my 06 GTO where it would drip a few drops from the inspection cover but everything inside was dry.

03-10-2026, 09:33 PM	#14
IT Cowboy Senior Member Join Date: Jan 2025 Location: Arizona in a van down by the river Posts: 617	Re: Trans fluid drops out of the dust cover weep hole? The source seems to be running down the the inside passenger edge of the dust cover. I need to look at the flywheel closer. I agree if I have it out i might as well have it rebuilt. The shop I had it quoted gives a three year warranty. __________________ 1972 C10 Custom Deluxe Highlander 402 Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

03-10-2026, 09:50 PM	#16
IT Cowboy Senior Member Join Date: Jan 2025 Location: Arizona in a van down by the river Posts: 617	Re: Trans fluid drops out of the dust cover weep hole? Would a new torque converter help it be more responsive or hook up quicker or a new converter with different specs __________________ 1972 C10 Custom Deluxe Highlander 402 Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility.

03-11-2026, 03:34 PM	#19
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 4,035	Re: Trans fluid drops out of the dust cover weep hole? Can't believe today's prices. Of course, I'm livin' in the past! But even back in 2015, a friend of mine rebuilt a TH350 I had using about $100 in parts. The trans was out of the truck when I took it to him, and he spent around 2-3 hours going through it. I then added a $50 TransGo kit to the valve body, and bought a reman converter for $60 from TranStar. I'd guess parts must cost 2x as much now, and labor is $300/hr. __________________ Mike 1969 Custom/10 LWB -- owned for 37 years. 350/TH350, 3.08 posi, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. Hedman stainless headers. Old Air installation in progress. 1982 Custom Deluxe 10 SWB -- converted from 250-six to roller cam 350 w/ Vortec heads -- sold 1981 C10 Silverado LWB, 305, TH350C -- sold, but wish I still had it! 1969 C10 (not the current one) which I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 26 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; 03-11-2026 at 06:40 PM.



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