Maintenance Schedule on Dmax trucks?

dvdprL · April 1, 2017

Guys, I keep reading tons of different conflicted information through my searches. I know a lot of you here have had many diesel trucks over the years and have found what is necessary for a healthy long life.

This is my first diesel, so just looking for recommended oil change intervals, fuel filter intervals, fluid changes, etc. I DO NOT tow anything heavy, occasional bass boat or wakeboard boat. I don't do a ton of driving right now with a 6 month old baby, so it's really sitting more than being driven unfortunately right now.

Thank you guys for any information! I'm always skeptical to listen to the manual "recommendations", as they don't give a **** what happens to your vehicle after the warranty is up.

I usually sell my vehicles after a few years and get something new, but I'd like to maintain it as if I were going to keep in for 10 years in case I decide to do so.

newdude · April 1, 2017

I DO NOT tow anything heavy, occasional bass boat or wakeboard boat. I don't do a ton of driving right now with a 6 month old baby, so it's really sitting more than being driven unfortunately right now.

First off...I'm gonna be that guy...awfully expensive truck to operate for not towing heavy or making $$ off of it...that being said and out of the way...

Oil and oil changes. Plenty to choose from. GM factory fill is Mobil Delvac 1300. We use it at work, no issues. You could go synthetic if you wanted, say Mobil or Shell Rotella. Really, any good 15w40 will work of your preference. Your first two are free from GM as well, including DEF top off. If you stay with Delvac, I would change it in the 4000-6000 mile range that way its timed nicely with your tire rotation and DEF tank usage. Figure $60-100 for an oil change depending on if you do it or a dealer/shop does it. 10 quarts is capacity.

DEF. Its going to last you about an oil change per tank. Figure 4000-6000 miles. Make sure its fresh. Everyone puts the fill date on the jug somewhere. DEF does have a shelf life based on temperature. Anything over 80 degrees storage temp will shorten the fluid life. So, make sure its no older than 6-8 months since the jug was filled. A 2.5 gallon jug will run $15-22.

Transmission. Allisons have two filters. Internal pan, and external spin on. I'd say 30k on the external? 50k on the internal and a fluid change. Spin on runs $45-55. GM dealers have a blue painted Allison OE filter. Allison OE will be red. You could go either way, GM from a dealer or an Allison from any local Allison dealer (think truck shop). As for transmission fluid, GM specs Dexron 6.

Fuel/Air/Oil filters. OEM. OEM only. GM has seen issues arise with aftermarket fuel and air filters. I'd change the fuel at 10-15% life left. Fuel filter runs $50-60.

Regen. If you are driving and your idle jumps up 200-400rpm sitting still in Drive, you are probably doing a passive regen. Make sure you keep moving so it can burn the DPF off properly. The better you are at doing that, the less your chances are of having an Active regen where the message pops up on the dash telling you to drive over 55mph. A passive regen takes 10-15 miles of driving.

calgator73 · April 1, 2017

Guys, I keep reading tons of different conflicted information through my searches. I know a lot of you here have had many diesel trucks over the years and have found what is necessary for a healthy long life.

This is my first diesel, so just looking for recommended oil change intervals, fuel filter intervals, fluid changes, etc. I DO NOT tow anything heavy, occasional bass boat or wakeboard boat. I don't do a ton of driving right now with a 6 month old baby, so it's really sitting more than being driven unfortunately right now.

Thank you guys for any information! I'm always skeptical to listen to the manual "recommendations", as they don't give a **** what happens to your vehicle after the warranty is up.

I usually sell my vehicles after a few years and get something new, but I'd like to maintain it as if I were going to keep in for 10 years in case I decide to do so.

Fuel filter is cheap ~28 wrench is about 9. Oil filter 7. Allison filter is factory ~12. Rotella t6 is about 55. And Walmart def is 8 per 2.5g jug.

At 50k I've had both tranny filters serviced (not necessary only external and fluid) still original fuel filter at 52k and 12%. Def lasts about 6k assuming you put two jugs in at 5% remaining. Oil changes are done<5% and last about 7500 miles.

Depending on your annual mileage it might be advisable to decrease your intervals.

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Rvduck · April 1, 2017

I had my 08 Duramax for 8 years and it was only serviced by me, no free oil changes in 08. I am a low mileage driver because the truck was mainly for recreation pulling a 12000 pound Fiver and hauling a slide in camper.

I only had 50000 miles when I ordered my 16 and made the trade in deal. I used to change the oil every 5000 miles and I went to Rotella synthetic when the truck was 2 years old. I changed the fuel filters when the computer showed 50% left. I changed the spin on tranny filter at 5000 miles and never touched the tranny again. Checked the fluid, on the dipstick and it was fresh and always ran cool. My 08 had a magnetic washer that stuck on the trans fillter and would be easy to throw away, not sure about the new ones. I found a genuine Allison spin on filter on EBay for 1/3 of what my Dealer wanted and found and bought Delco oil filters and good fuel filters on line at much cheaper prices than my dealer. I kept all my receipts in case I ever had a warranty claim and when I brought the truck in for the appraisal check ( I got a very fair price for this truck from the dealer I ordered from and I know the market ) They never once asked about the service record for this truck because I told them I sold vehicles for a living and I know if they start asking service questions like, when did you last have the brakes checked, there is only one reason they do this, to devalue your trade. They check it over, they service it before they sell it, the history means nothing. When I sold new Ford vehicles, many customers gave me a folder of service receipts. We thank them, they get thrown in the garbage without being looked at. Enjoy your new truck.

jhplak325 · April 1, 2017

Fuel filter is cheap ~28 wrench is about 9. Oil filter 7. Allison filter is factory ~12. Rotella t6 is about 55. And Walmart def is 8 per 2.5g jug.

At 50k I've had both tranny filters serviced (not necessary only external and fluid) still original fuel filter at 52k and 12%. Def lasts about 6k assuming you put two jugs in at 5% remaining. Oil changes are done<5% and last about 7500 miles.

Depending on your annual mileage it might be advisable to decrease your intervals.

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Still original fuel filter? Per GM, should be changed every 2 years, 22,500 miles or per the DIC, whichever comes first.

OP, I change the oil between 4,000-4,500 miles, at 18,000 miles I change air filter, fuel filter and external trans filter. DEF I add 2.5 gallons when truck shows 29%.

About to turn 36,000 miles and getting ready to change the filters again.

calgator73 · April 2, 2017

Still original fuel filter? Per GM, should be changed every 2 years, 22,500 miles or per the DIC, whichever comes first.

OP, I change the oil between 4,000-4,500 miles, at 18,000 miles I change air filter, fuel filter and external trans filter. DEF I add 2.5 gallons when truck shows 29%.

About to turn 36,000 miles and getting ready to change the filters again.

Reread your manual. "2500/3500 series vehicles only.For severe commercial usevehicles, see Special Application

Services on page 11-7" That's where your 2 year limit kicks in.

There's no problem with decreasing your intervals. But there are no issues with simply following your manual.

How do you get your DIC to indicate 29%? Supposed to kick in with 1000 miles remaining.

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dvdprL · April 2, 2017

Thank you all of the replies. Keeping this stuff written down and handy!

I do about 18-20k a year driving, however with my wife's job we are stuck living across the country for the next week 18 months... hence the not driving much. 5k miles since August. Once back in California, my driving will go up significantly.

I appreciat all the info!

jhplak325 · April 2, 2017

Reread your manual. "2500/3500 series vehicles only.For severe commercial usevehicles, see Special Application

Services on page 11-7" That's where your 2 year limit kicks in.

There's no problem with decreasing your intervals. But there are no issues with simply following your manual.

How do you get your DIC to indicate 29%? Supposed to kick in with 1000 miles remaining.

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I know what that page says and this is not listed under Services - Severe, it is listed under Special Application section which are 2 different sections for maintainence - Replace the fuel filter when the CHANGE FUEL FILTER message in the Driver Information Center (DIC) comes on. See Fuel System Messages on page 5-13. If the fuel filter has not been replaced, or if the vehicle has been driven 36 000 km/ 22,500 mi or more since the fuel filter was last replaced, replace the filter and reset the message. The diesel fuel filter may need to be replaced more frequently, based on biodiesel usage, driving in climates with severe dust, off-road driving, or towing a trailer for extended periods. The fuel filter should be replaced at least every 2 years.

Based on the above, you should have already replaced the fuel filter twice now due to mileage.

When the LML came out the change interval changed, before this version of the Duramax, change interval was much sooner.

Checkout the Duramax forums, a lot of good info.

When the DEF is greater than 30% left, the dash shows "OK", 30% and under it will show percantage (I add 2 1/2 gallons around this time). When you get to 1,000 miles left, DEF tank is low and you can add 5 gallons. If you can't find the DEF info when scrolling through the DIC, it might be turned off and needs to be turned on.

OP - I run similar mileage per year and that is a mix of towing and not towing.

calgator73 · April 2, 2017

very confusing topic. Asked dealer about this and response from diesel tech was to ignore special app section (for ambulances) and obey the messages. He even stated I should get at least 50k. I've been carrying a filter, wrench and bleeder screw for 20k miles.

I only look at the def level when I get the 1k warning=22%=1.16 remaining. By waiting until I have 5% remaining I can add 5 gallons without it burping... Capacity is only 5.3. how can you possibly add 5 gallons with 1k warning?

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jhplak325 · April 3, 2017

DEF tank holds more than 5.3 gallons, GM says 5.3 gallons so it will allow for expansion in the winter time since DEF will freeze around 12f degrees.

Someone on one of the Duramax forums figured the tank holds just over 7 gallons.

You definitely want to keep up with fuel filter changes, you don't want to give GM a reason to decline warranty if the CP4 pump goes. That is a very expensive repair.

Just posted the other day - http://www.duramaxforum.com/forum/maintenance/896450-my-fuel-filter-nightmare.html

I have not added yet, but will be next filter change - https://www.madjackdiesel.com/2015-Up-LML-Fuel-Filter-Access-Door-p/ffaplml15.htm

Chevor · April 3, 2017

I run my 2010 upwards of 100k a year. Mainitance mileage intervals get stretched out, truck is still serviced at least once a month. Oil typically 18k interval, Trans 75k and spin on filter change. 810k I have never changed internal filter. Fuel filters, before after market FASS system added was going every other oil change about 36k.

IMO the worst thing you can do for a vehicle is let it sit.

Run at least once a month.

If under 5000 miles a year change oil yearly. Might stretch fuel filter and Trans fluid change to two years.

calgator73 · April 3, 2017

DEF tank holds more than 5.3 gallons, GM says 5.3 gallons so it will allow for expansion in the winter time since DEF will freeze around 12f degrees.

Someone on one of the Duramax forums figured the tank holds just over 7 gallons.

You definitely want to keep up with fuel filter changes, you don't want to give GM a reason to decline warranty if the CP4 pump goes. That is a very expensive repair.

Just posted the other day - http://www.duramaxforum.com/forum/maintenance/896450-my-fuel-filter-nightmare.html

I have not added yet, but will be next filter change - https://www.madjackdiesel.com/2015-Up-LML-Fuel-Filter-Access-Door-p/ffaplml15.htm

That incident is crazy! Surprised the water in fuel alert didn't go off. I'm going to order that hatch and do my filter when it comes in. See how bad it looks.

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ShotgunZ71 · April 3, 2017

My truck is 19 mos old and has 21k miles on it. I'm close to my 4th (and last) complimentary maintenance at the dealership. I thought of having them change the fuel filter while they have it if they don't charge an outrageous price. If not, I'll do it myself on the following oil change,which should be pretty close to the 2 year mark. The filter monitor is currently at 61%.