josh mcquown

My transmission crapped out on the freeway last week. The transmission is currently being replaced with a refurbished unit. I'm also having the oil pump belt and rear main seal replaced while the transmission is out. My truck was out of warranty, but I contacted GM support and they are covering 70% of the transmission cost. So basically, the total is costing me what it would have cost to have the oil pump belt done. The oil pump belt was a fraction of what it should cost since transmission R & R is being covered. I do not know exactly what failed in the transmission. The dealership is not opening the transmission since its being replaced. I doubt I'll ever know what failed. If your truck is making a whining sound, I would take it to the dealer now so that if it fails outside of warranty you have documentation that you were concerned about the noise at 25K and a dealership inspected the noise. How does your truck shift? I noticed a hard downshift while on the frwy, letting off the accelerator and on the brakes.

Thank you all for the comments / feedback. Here’s a quick update. I spoke to a GM Corporate customer service rep. GM has what they call a “just out of warranty” program, which covers 6000 miles or 200 days over the warranty. GM is covering 70% of the transmission repair. Working with GM customer service directly has been a blessing. The customer service rep also mentioned, if I ever want GM to review a repair bill, just send them a copy and they will do their due diligence. I’ll post an update with the total cost and what was done when I pick the truck up. It should be about 10 days. I hope to get some feedback as to what failed in the transmission, but I doubt the dealership will open the tranny.

Turns out it was my transmission! I thought it was the engine considering it followed RPM. Guess I'll stick to woodworking.

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...

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?

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?

I have a 2021 GMC Sierra 1500 AT4 3.0 Duramax, with 105,000 miles. I have recently noticed a whining noise that follows the engine RPM. I tried to access the idler pulley to verify its not the problem, but it's very difficult to reach. The whining does not sound like it's coming from the front or top of the engine bay. The whining sounds like its coming from the back, lower portion of the engine, where the transmission mates. My fear is that it's the engine oil pump that is sandwiched between the engine and transmission. There is a recommended oil pump belt replacement at 150k miles. Has anyone else experienced this issue? Has anyone done the oil pump belt replacement? I'm curious what it costs and if I should go ahead and have it done now and have the engine oil pump pulley replaced to avoid a catastrophic issue. I drive a ton, about 50k a year. Any feedback, thoughts, solutions, etc are greatly appreciated!

Cognito UCAs with Elka 2.5 DC reservoirs 1" front and rear to level the truck- What a difference! I haven't had an opportunity to take it off road yet, but the difference on the road is substantial. I drive my truck a lot, 50k miles a year. It's a 2021 Sierra AT4 3.0 duramax and has 70k. With 70k miles my suspension was really bad, the truck bounced around specially when hitting rough road going around freeway on ramps. I hit these same spots now and the truck feels very stable. I'm still running stock wheels with 1" hub centric spacers to clear the UCA's. My off road driving consist mostly of forest service, fire roads and light desert use. I think set up is going to serve my needs perfectly.