2020 3.0 Duramax Oil Pump belt due soon - any experiences?

SC4R3C120W · November 7, 2023

I currently have 106,000 miles on my LM2, and i'm wondering when i should change the oil pump belt. Has anyone had any kind of experience with the dealer doing it? Cost?

I believe it was listed at one point at being due around 120k, but something makes me think it was changed to 150k?

Also, i am now starting to hear a higher pitched wine at start-up and lower RPMs and seems to match RPM. Is the turbo vane rod having something to do with it? Maybe a slight exhaust leak? again, looking for anyone that has similar experience with potential issues.

BigBadSierra · November 7, 2023

Well it 150,000 miles on the LM2 it's 200,000 miles on the LZ0 but get this it's the exact same part number for the belt for both. So read into that as to what you think but I can't see the same belt wearing out fast in one engine and not the other.

redwngr · November 7, 2023

I would expect that GM's documents have changed the recommendation for the LM2 as well -- for the reasons @BigBadSierra posted.

Perhaps @newdude can tell us for sure?

Maybe also has info about best way to do the change?

newdude · November 7, 2023

LM2 maintenance charts are all 15yr/150k whichever comes first for the oil pump belt. Could you in theory take it to 200k? I suppose so.

Transmission has to be removed. Some one time use parts required too and a few special tools required. Book time is 16.8 hours for 4wd, 13.9 hours for 2wd,

One time use parts:

Automatic Transmission Flex Plate Bolt [8x]

Exhaust System Front Gasket

Oil Filter

Timing Chain Lower Cover

Transfer Case Front Output Shaft Boot Clamp

Transfer Case Adapter Gasket

Transmission Fluid Cooler Pipe Seal [2x]

Transmission Fluid Cooler Seal

Silverado4x4 · November 7, 2023

Probably looking at in the neighborhood of $3000.00 to have it done.

SC4R3C120W · November 7, 2023

1 hour ago, newdude said:

LM2 maintenance charts are all 15yr/150k whichever comes first for the oil pump belt. Could you in theory take it to 200k? I suppose so.

Transmission has to be removed. Some one time use parts required too and a few special tools required. Book time is 16.8 hours for 4wd, 13.9 hours for 2wd,

One time use parts:

Automatic Transmission Flex Plate Bolt [8x]

Exhaust System Front Gasket

Oil Filter

Timing Chain Lower Cover

Transfer Case Front Output Shaft Boot Clamp

Transfer Case Adapter Gasket

Transmission Fluid Cooler Pipe Seal [2x]

Transmission Fluid Cooler Seal

always a plethora of knowledge.

Since i had trans fluid and filter replaced at 100k, i should at least wait to 150k or 200 to have this performed as i'll have to change it or add to it again. I'm only 2WD, so less hours and hopefully less cost. i just like being proactive with maintenance as i drive 30k miles a year lately and need/want this to be dependable. Still love this truck as it has a 3" lift, aftermarket true 33" tires, and still gets me 28 - 33mpg constantly going to work and back (and thats for the life of the truck, not just one or 2 fill ups).

Transient · November 8, 2023

This is the biggest reason I didn't buy the Duramax. However, most people would have their truck paid off by the time this expense comes around.

KARNUT · November 8, 2023

The odyssey had a big maintenance bill at 100K miles as most vehicles do. Plugs, timing belt, brakes, transmission fluid, tires and brakes. You also have to keep in mind other wear items. I’d usually trade before. It’s also about the time extended warranty runs out along with payments. With most vehicles life expectancies at around 200K miles the second 100K miles should be cheaper. I did the maintenance on two vehicles for the first time. Both have past the cost per month versus payments with the high 100K maintenance. It’s a new road for me to travel with higher mileage vehicles. The savings are adding up. My next vehicle will be a cash buy with the savings. It’s like when you first start to save money. It becomes intoxicating you want to do more. Do I really want that payment? It took me 5 decades.

Jay P · November 8, 2023

As of 2023 the oil pump belt is 15 years/200k miles. If the belt part hasn't changed then no reason an earlier model can't go 200k. Attached is a pic from our 23 Tahoe diesel supplement.

SC4R3C120W · November 8, 2023

Thanks all for the confidence in waiting for a little more mileage. Unfortunately, i believe i traced the noises i was hearing to the transmission, so i'm taking in to the dealer today.

It started a fweek or two ago where i heard a higher pitch whining coming from the side/underneath. Just within the last day or 2 it sounds like there's material spinning around and making a clunking/grinding noise. truck still drives and shift smooth with no issues other than the noise, but i'm convinced it's a ticking time bomb. this morning i had it on cruise control going 70mph and the thing shuddered on me. scared me enough to call the appointment in as soon as they open.

redwngr · November 8, 2023

The SUV's (even 2024) are still using the LM2, while the pickups use the LZO.

Another reason to wonder if perhaps 200,000 might be reasonable for all 3.0's

SVG · November 9, 2023

19 hours ago, redwngr said:

The SUV's (even 2024) are still using the LM2, while the pickups use the LZO.

Another reason to wonder if perhaps 200,000 might be reasonable for all 3.0's

Good point. I hadn't thought of that.

bartonjude · November 10, 2023

What happens if the belt snaps?

redwngr · November 10, 2023

12 hours ago, bartonjude said:

What happens if the belt snaps?

I'd expect the DIC would indicate engine oil pressure is low and that the engine should be shut off.

(This would so you can get to the shoulder of the road to stop)

Edited November 10, 2023 by redwngr

Bikerjon · November 10, 2023

On 11/8/2023 at 1:57 PM, SC4R3C120W said:

Thanks all for the confidence in waiting for a little more mileage. Unfortunately, i believe i traced the noises i was hearing to the transmission, so i'm taking in to the dealer today.

It started a fweek or two ago where i heard a higher pitch whining coming from the side/underneath. Just within the last day or 2 it sounds like there's material spinning around and making a clunking/grinding noise. truck still drives and shift smooth with no issues other than the noise, but i'm convinced it's a ticking time bomb. this morning i had it on cruise control going 70mph and the thing shuddered on me. scared me enough to call the appointment in as soon as they open.

Very sorry to hear. Let us know how this works out. I have heard about transmission pump idler gear and bearing failures in the earlier 10 speeds.