2024 2500 transmission leak

stympyctlan · June 23, 2023

Purchased new 24 2500 gas with the 10 speed allison. Just a bit over 800 miles and discovered a drip at the bellhousing inspection port. Found a TSB that pertained to the 2020 through 2022 with the exact issues I was experiencing.

Took truck in for service a few days back and they uv checked to confirm the fluid in fact was transmission fluid which is now confirmed.

Transmission has been pulled however I am being told that the seals they don't have part numbers for so they can't order them. They tell me the transmission in the gas truck is so new that they don't have the part numbers in the catalog in order to order them.

The service manager has requested that chevrolet approve the install of a totally new transmission in order to get me back on the road.

I hope this new transmission doesn't show up on the carfax report or else the truck will have a substantially deflated value.

Dustin Marshall · June 23, 2023

Curious how bad the leak was?

stympyctlan · June 27, 2023

I wouldn't really call it a leak more of a drip. Sitting still there was never any fluid on the ground that I could see. My thought is probably more sepage while traveling.

So after a week of sitting at the dealer with the transmission removed from the truck, the dealer finally has authorization to replace the transmission with a new transmission. No rebuild no remanufactured. The truck has less than 1k miles.

The service manager says he identified the seals and wanted to replace the torque converter and seal as well. He says there are no parts numbers available yet due to the year of the truck. He also stated that he would prefer a new transmission instead of new seals just because of the low mileage.

The transmission will be shipped which takes about 5 days to CT so I'll be without my brand new truck for another week

Edited June 27, 2023 by stympyctlan

stympyctlan · June 27, 2023

stympyctlan · June 27, 2023

Just now, stympyctlan said:

Not the best picture but this is the inspection port at the front of the transmission adjacent to the oil pan.

the8rotor · June 30, 2023

Yikes... good they are doing a full replacement. I'm going to check under mine now

Haoleguy · July 1, 2023

Sounds like you have a decent dealer with good service. New instead of repair seems prudent given the newness of the gas-Alison combo. Report back when you have update. Wonder if Chevy will inspect removed transmission to get an idea of what went wrong?

stympyctlan · July 7, 2023

Good evening all. Just picked the truck back up this afternoon.

They ended up doing the full transmission swap. Took a lot longer than I think it should have but I guess that's the ways things work out.

Regardless I had a long conversation with the service manager and he says they really couldn't pinpoint exactly what the failure was because everything looked good by eye. Obviously the leak was only under pressure which is why I never say any puddles on the ground.

I would certainly hope GM digs in and finds out where the leak was coming from.WWon't sure what year gm stopped installing dipsticks in these trucks but the refill process is rather tedious with these 10 speed allisons.

I wad informed that the learning procedure for the new transmission will feel odd for the new few hundred miles and said to change up driving habits between town and highway Driving. There are some harsh shifts at slow speed and some what feels like being bumped from behind by another vehicle.

I'll check back in a few weeks to let you all know how the shifting settles in.

UWSkier · July 7, 2023

2 hours ago, stympyctlan said:

Good evening all. Just picked the truck back up this afternoon.

They ended up doing the full transmission swap. Took a lot longer than I think it should have but I guess that's the ways things work out.

Regardless I had a long conversation with the service manager and he says they really couldn't pinpoint exactly what the failure was because everything looked good by eye. Obviously the leak was only under pressure which is why I never say any puddles on the ground.

I would certainly hope GM digs in and finds out where the leak was coming from.WWon't sure what year gm stopped installing dipsticks in these trucks but the refill process is rather tedious with these 10 speed allisons.

I wad informed that the learning procedure for the new transmission will feel odd for the new few hundred miles and said to change up driving habits between town and highway Driving. There are some harsh shifts at slow speed and some what feels like being bumped from behind by another vehicle.

I'll check back in a few weeks to let you all know how the shifting settles in.

That's a great way to describe how mine feels when downshifting into first gear approaching a stop sign or stoplight. It makes nice linear stops kindof a pain. I have about 400 miles on my truck so far so I'm hoping that improves. It's going on a 4000 mile RV towing trip pretty much the second it hits 500 miles. Maybe that'll teach that transmission a thing or two.

Pryme · July 11, 2023

On 7/6/2023 at 5:41 PM, stympyctlan said:

Good evening all. Just picked the truck back up this afternoon.

They ended up doing the full transmission swap. Took a lot longer than I think it should have but I guess that's the ways things work out.

Regardless I had a long conversation with the service manager and he says they really couldn't pinpoint exactly what the failure was because everything looked good by eye. Obviously the leak was only under pressure which is why I never say any puddles on the ground.

I would certainly hope GM digs in and finds out where the leak was coming from.WWon't sure what year gm stopped installing dipsticks in these trucks but the refill process is rather tedious with these 10 speed allisons.

I wad informed that the learning procedure for the new transmission will feel odd for the new few hundred miles and said to change up driving habits between town and highway Driving. There are some harsh shifts at slow speed and some what feels like being bumped from behind by another vehicle.

I'll check back in a few weeks to let you all know how the shifting settles in.

I believe the 2020 year they stopped putting a dipstick in. Many of us installed one though using factory parts on our 20-23 trucks. 24 I believe it’s not possible.

the8rotor · July 13, 2023

On 7/6/2023 at 10:29 PM, UWSkier said:

That's a great way to describe how mine feels when downshifting into first gear approaching a stop sign or stoplight. It makes nice linear stops kindof a pain. I have about 400 miles on my truck so far so I'm hoping that improves. It's going on a 4000 mile RV towing trip pretty much the second it hits 500 miles. Maybe that'll teach that transmission a thing or two.

4200 miles on mine and I do have a harsh downshift to first on a decline. Not as bad as what my 6L90 used to do, but it definitely has softened up with the abuse I've given the truck over the last month.

GMCustomerService · July 19, 2023

On 7/12/2023 at 10:18 PM, the8rotor said:

4200 miles on mine and I do have a harsh downshift to first on a decline. Not as bad as what my 6L90 used to do, but it definitely has softened up with the abuse I've given the truck over the last month.

This is certainly not what we like to hear, the8rotor. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your truck having hard downshifts. To do so, please send an email to [email protected] with ATTN: the8rotor/GM Trucks in the subject line.

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