Transmission fluid leak?

kpanza · March 17, 2020

Hello All,

New 2020 Sierra SLT owner here (longtime GM customer). Just got the truck (6.2L, 10spd, 4x4 Crewcab, max tow) last week. 300 miles on it. Loving it, so much better ride and smoothness than my '10 Silverado or '13 F150, both also Max Tow setups just like this. Anyways, I helped a friend get a 2020 Sierra SLE back in September, and about a month after he got it, he was at my house with it...I noticed tranny fluid on my driveway when he went to leave...got underneath and could see tranny fluid all over. I also saw engine oil (he has the 2.7L turbo 4 and the 8spd). His truck was at the dealer for 3 weeks as they had to wait for both an engine oil pan and tranny pan!

So, when I saw the dreaded tranny fluid puddle on my driveway this weekend, I couldn't believe it! Brand new truck, 300 miles on it. Crawled underneath, trans fluid dripping. Appears to be at bellhousing area, above the pan? But I know it can fly all over. I assume it has been leaking since the day I got it last week, but this was the first time I backed into the driveway, and wherever it was collecting, the angle of the driveway made it drain onto the concrete.

Not bashing on GM here, had plenty of problems even with my wife's Lexus, but is this a known issue? I searched and see a LOT of Ford forum guys complaining about the one time use plastic pans leaking, and obviously it's all shared between GM and Ford on this 10 speed. My friend's truck has the 8 speed. Who knows. Just hoping that it doesn't take weeks to get a pan if that is the problem? Thanks for any input if you have experienced this! Going to dealer tomorrow with it. Any other TSBs on this? I saw one for the SUVs with the 10 speed about the cooler line retaining bolt leaking?

kpanza · March 18, 2020

No one else had this issue? Truck is at the stealership now, I will post up what they find. Service advisor seemed pretty used to this complaint, said they even have an aftermarket silicone sealant that works better than the factory stuff on the plastic pans...we will see.

kpanza · March 19, 2020

So, lucky me. My 2 week old truck is having it's transmission removed from truck, dealer tech says the torque converter seal is cause of the leak. When I saw the fluid dripping down from the bellhousing area last week, I thought there was no way it could be the torque converter already! The dealer thinks it was bad from factory, and should have been caught during the PDI, was probably leaking already. Wow, I am finding it hard to believe...2 week old truck, 300 miles on it...I've had a lot of GMs, but my faith is definitely waning. Really hoping that this is the last issue that pops up, but reality says it won't be.

Anyways, let's see if this gets resolved remotely quickly...dealer has "No ETA at all on when this will be fixed"...great.

kpanza · April 10, 2020

So, the truck was at the dealer for 2 weeks, and they said they got the parts and fixed it. Drove it home and it sat for a few days, until I drove it to get some groceries and firewood last Saturday. Go to move it Sunday again, and what do I see? Yep, a big red puddle of transmission fluid on the driveway AGAIN. Words fail me. They either didn't actually fix it, or the tech is a dumbass, or the transmission has some sealing defect. Unbelievable. Goes back in again Tuesday, can't wait to hear what they say now. If it sits there another two weeks, will be time for lemon law. I've owned about a dozen GMs in my life, this is looking to be the worst of them...crazy. I love the truck, but this sucks.

kpanza · April 10, 2020

One positive note - after our monsoon-like rain this week in So Cal, at least my window isn't leaking!

ttower · April 27, 2020

Any update? Just bought 2020 Sierra w/6.2. looks like i have a leak similar.

Sent from my SM-G973U using Tapatalk

kpanza · April 28, 2020

They had it for two weeks, replaced the torque converter seal. Leaked even worse. Has been back at dealer for last two weeks, they are claiming pump and seal need replacing now! But no idea on parts availability, so it's just sitting there. Thursday will mark 30 days out of service, at which point I will likely go Lemon Law. Ridiculous.

My buddy has an SLE, his was in shop 6 weeks total, had trans and engine oil leaks...starting to wonder?? His was the 2.7L four, they had no engine pans available because of strike when his was in late last year.

GMCustomerService · May 6, 2020

Hi, guys. Please know, customer satisfaction is extremely important us. Our team would be more than happy to take a closer look into these concerns on our end. To do so, please send an email to [email protected] ATTN: Forum Username/GM Trucks with your contact information, VIN, brief description of your concern, and preferred dealership. We look forward to hearing from you. To learn more about GM's privacy policy, please visit http://bit.ly/2h3ZUnC.

Aleigha W.

Shiva · May 28, 2020

That sucks man. I just got my 2020 1500 Denali 6.2 less than a week ago. Noticed engine oil dripping from the front. Crawled underneath and noted a lot more oil on the plastic skid plate and the frame and even more on front of engine. Also saw some oil pooling on the strut tower in engine on passenger side. Less than 200 miles on it!!! WTH?

How could they miss this during the PDI? Taking it to dealer in the morning for them to have a look. I will ask them to check the tranny for leaks too.

davester · May 28, 2020

5 hours ago, Shiva said:

That sucks man. I just got my 2020 1500 Denali 6.2 less than a week ago. Noticed engine oil dripping from the front. Crawled underneath and noted a lot more oil on the plastic skid plate and the frame and even more on front of engine. Also saw some oil pooling on the strut tower in engine on passenger side. Less than 200 miles on it!!! WTH?

How could they miss this during the PDI? Taking it to dealer in the morning for them to have a look. I will ask them to check the tranny for leaks too.

Well, are you certain it was leaking then? Sounds like it would be leaving a spot anywhere you park, and you probably would have noticed it sooner if it was.

Heck, I've got a 15 year old truck, and I check for visible drips when I walk up to it.

Edited May 28, 2020 by davester

Bob2C · May 28, 2020

Wondering if it could be engine oil cooler lines. Mine developed a leak at where it’s crimped. Sits in the front of the engine above the plastic shield. Typical problem from what I read

Sent from my iPhone using Tapatalk

Shiva · May 28, 2020

I've read all the horror stories on here about the oil cooler lines after I discovered the oil residue and droplets this past Tuesday. It was not low on oil though right on the full mark. It had 7 miles when I picked it up and 125 miles when I discovered the leak.

I took the truck into my dealer today and also showed them photos what I saw. I didn’t want to delay scheduling an appointment in case it caused further damage to the engine.

The Tech did note the oil upon his inspection. The service Consultant said that he cleaned up the oil and added a dye to the engine. He drove it for 6 miles then inspected it with a black light. They could not detect anything. He also noted that there was no drop in oil level when he checked via the dipstick. He does not think it is the oil cooler lines like many others on the truck forums have reported.

I just approved their request for a manager to take the truck home tonight and they will inspect it again in the morning after the oil has been given some time to work it’s way through.

If they don't find anything in the morning it may be a possibility that some yahoo spilled oil in there during the fill at the factory???

kpanza · May 29, 2020

They said they did the dye in my transmission, and found "no further leaks"...yet, couple days later when I got it home, trans fluid all over driveway again. And just FYI, my truck has now been at the dealer for 60 DAYS now! GM has approved a buyback, but there are literally no trucks comparable to mine available. Trying to see if GM will ship something from a dealer 1000 miles away, but so far no answer. My dealer rep has argued for a complete NEW 10 speed from GM, but so far nothing. So ridiculous. On my 4th payment, and driven the truck all of 300 miles over a couple weeks.

Shiva · May 30, 2020

On 4/27/2020 at 9:14 PM, kpanza said:

They had it for two weeks, replaced the torque converter seal. Leaked even worse. Has been back at dealer for last two weeks, they are claiming pump and seal need replacing now! But no idea on parts availability, so it's just sitting there. Thursday will mark 30 days out of service, at which point I will likely go Lemon Law. Ridiculous.

My buddy has an SLE, his was in shop 6 weeks total, had trans and engine oil leaks...starting to wonder?? His was the 2.7L four, they had no engine pans available because of strike when his was in late last year.

Curious... What is the build date of your truck? My Denali 6.2 is 2/20. From Mexico.

Got got mine back they did the dye in the engine oil washed off the engine bay and drive for 6 miles. Couldn't find any oil leak. The mgr took it home last night to test and let the oil work through. No oil leak detected. The oil at the dip stick has been full from day one.

I'm hoping it was just some Yahoo in Mexico who couldn't aim the oil hose right and spilled it in the engine bay.

I guess I will just keep an eyes on it and check with my own black light at home.

Shiva · May 30, 2020

On 5/28/2020 at 1:26 AM, davester said:

Well, are you certain it was leaking then? Sounds like it would be leaving a spot anywhere you park, and you probably would have noticed it sooner if it was.

Heck, I've got a 15 year old truck, and I check for visible drips when I walk up to it.

I couldn't be certain but that much oil residue and droplets on a new truck with 6 miles on it is alarming! The dip tick measured full though.

Got the truck back today. They wash off the oil, applied the dye and drove it. Even kept it over night and took it home for another 20 miles for it to work through. They couldn't find a leak and no new oil was present.

I hope it was just the person on the line filling the fluids spilling oil in the engine bay.