Balls in my transmission?! 2021 GMC Sierra 1500 AT4 3.0.

[josh mcquown]

I recently performed a transmission filter and fluid change on my 21 GMC Sierra 1500 AT4 with 3.0 diesel. I thought I had this done at 40k miles, but looking back at my mainteneance records the dealership only flushed the fluid. I had hard downshifting when letting off the gas and I'm at 102k miles so I figured I would change the fluid myself. After dropping the pan, I found A LOT of sludge on the bottom of the pan and small metal shavings near the pan magnet. Not too concerning since I bought the truck new and the pan had never been dropped. What is concerning, I found about 8 - 10 of these tiny steel balls stuck to the magnet. In my opinion, they look too small to be transmission parts. What are they? Why are they in my transmission? 

 

It's no wonder why GM is having so many transmission problems. This is my first GMC and likely my last. I don't think I'm going to get 150k miles before a major repair is due. 

 

Please see the photos. Does anyone know what these are? 

[Okievision]

Quote

terrifying is what they are! Other than that, no idea

 

[silveradosid]

they all look to be the same size, you have a bearing failing in the tranny

[SVG]

 I agree with @silveradosid , looks like a bearing is coming apart.

OP, yours is the highest mileage 3.0 I can recall so I and others will be watching your experiences closely.

 

Please keep us updated.

[newdude]

Definitely a ball from some sort of bearing.  The valve body balls are larger and aren't even metal on most of them anymore.  

Edited July 27, 2023 by newdude

[BIGDOGx]

Yikes, i imagine this is going to require a full rebuild right?

[Phantom 4D]

2 hours ago, newdude said:

Definitely a roller from some sort of bearing.  The valve body balls are larger and aren't even metal on most of them anymore.  

Ball. Not roller. 

[Phantom 4D]

Looks like a lot of sludge too. What did the filter look like? That so called fluid flush is a joke. A band aide. Don't know about the ten speeds, but it doesn't do anything for the eight speed shift issues. I too, would be interested in what you find. 

[64BAwagon]

The sludge wouldnt concern me at over 100k, the ball bearings do. 

I would have it torn down immediately, unfortunately it only going to get more expensive if its driven that way. 

[Bikerjon]

48 minutes ago, 64BAwagon said:

The sludge wouldnt concern me at over 100k, the ball bearings do. 

I would have it torn down immediately, unfortunately it only going to get more expensive if its driven that way. 

Agree this will require an overhaul.

[josh mcquown]

Update! I think my transmission failed today, at 104,766 miles. Just out of warranty. On my way to work, doing 75 down the freeway, the truck lost acceleration and felt like it was in neutral. I coasted off the freeway, and while coasting I heard a bit of grinding.  Once I stopped, the truck will not go into gear. It feels like it's in neutral. I was 60 miles away from home so I had it towed to the nearest dealership, where it is being diagnosed. 

 

I'd like to get some opinions on what to do? First off I drive a ton, I drive 40k miles a year. I still owe 30k on the truck and it has over 100K miles. The new transmission will be around $7500 and comes with 3 year 100k warranty. The dealership will give me 31k on the trade-in. Do I walk away from this thing and trade-in for a new GM? Have it repaired and keep driving it hoping that no other major issues pop up or have it repair and then trade it for something more reliable? I'm very hesitant to purchase a new GM vehicle. I've had both Ford and Toyota and both made it well over 100k before a major repair was done. My old Tundra 2006 went 220K miles. 

 

I want a truck that will last 300k miles. Am I asking too much out of new model GM 1500? Do you think a 2500 will last longer? 

[josh mcquown]

One other note, not sure if you all are aware but the 3.0 diesel oil pump is belt driven and it's on the back of the engine. The transmission must be removed to change the belt. The oil pump belt has a service interval of 150K miles. I didn't realize this when I bought the truck. After I hit 100k miles I called to get an estimate on the oil pump belt, I was quoted $4800. If I decide to keep the truck, I'll have the oil pump belt changed as well. 

 

I'd like to think "What else can go wrong?" - What a stupid thought... 

[MrMagloo]

Imho, I'd be very tempted to contact your local dealer you bought it from, and get them to push some consideration on the warranty 4K over is not much.  You might get some help, but you will probably have to get it back local.

 

Fwiw, KBB has a trade value of $228,657 to $32,482 and an Ave Retail of $31,656 to $35,761.  Perhaps that will help figure out the numbers.

[Bikerjon]

Josh this is a terrible situation. I would talk to the Sales Manager and the Service Manager at the dealer you bought it from. You will need to contact General Motors Customer Service and humbly request help from G.M. This truck is only two years old (give or take) regardless of mileage. Tell GM you love your truck and want to continue driving GM products. I think they may find it in their corporate hearts to help you with a "goodwill warranty" whereby they may pay for parts and you pay for labor or vice versa. Either way will save you a bunch of money and restore your faith in GM products. Give that a try. That is my best advice. Good luck and keep us informed about your situation.

 

[64BAwagon]

You could ask but I wouldnt go to Vegas and bet anything on it. Over 100k is a big ask. 

My 05 Duramax blew both head gaskets a little over 100k, a known issue on the LLY and the gaskets were blown on the fire ring at the rearmost cylinders, a mirror image of each other. That was a $4500 hit (in 2013 money)  and GM was no help.  I dont think you did yourself any favors by continuing to drive it after you pulled the pan.