Duramax/Allison Maintenance - do you follow GM Schedule or accelerate?

[Very Old Dog]

When I had my 3 Cummins, I followed the dealer recommended schedule of maintenance and never had a problem or a repair. When I went to the Chevy dealership, they really did not understand scheduled diesel maintenance and this made me a little less confident. The tech printed out a schedule from the GM thread he looked up and gave this to me. I just did a 7500 mile check up and I have about 6200 on it and was due for an oil change anyway. I did a LOF at the first 1000 miles and the second at LOF at 3000 miles. My plan is every 3000 miles from here on out. At this time, the tech checked all my vitals at my request, changed the external filter on the Allison, lube, oil and filter on the engine and rotated the tires. It says that the fuel filter can go 30k but that sounds like "BS". I use to to do it on the Cummins between 10 and 15k and never had a problem. And, I add Stanadyne Performance Plus every other tank of fuel. The differential got changed at 30K or a little earlier if I was doing a lot of heavy towing. The question is: what do you do for your Duramax/Allison and what is the correct schedule of maintenance? And how often do you change the air filter? (Is there a K/N solution?) I would appreciate your input and if there is a certified GM tech out there with a ton of experience, I would also appreciate your input.

[dmaxalliTech]

VOD....First, you cant overmaintain it..

You sound very aware of whats needed. Here is what I recommend and some may disagree:

1K--LOF and rear diff service
5K--Allison spin on filter, LOF, rotate
every 5K after, LOF, rotate at least everyother lof

If you are using a synthetic oil, you could go 10K on a lof

15K-- Fuel filter, and every 12-15k after that
30K--allison spin on filter, and every 30k after

This is close to GM recomendations. Some, including myself, get alot more involved in maint.

front diff, transfer case and rear diff fluid get dropped at about the 1k mark to install some quality fluid. Some switch the trans over to a synthetic.

There is aftermarket washable air filters out there that work good. As far as when to change the stock one...when its dirty, no set time for it. Just check it at least every LOF. Also check all fluid levels every LOF.

At about 75K or so, I would change the coolant.

You can email me for more in depth discussion regarding this

[chuntag95]

Why change the super coolant at 75k? Is that just a better safe than sorry? Would you go back red or green?

[Lonewolf867]

OK I know this is a bone headed question...AND I Know it is going to make me sound EXTREMELY STUPID...But what is LOF?

I know it is hard to type while you are laughing so hard..I SHOULD know this but.......

[56Nomad]

Lube Oil Filter smile.gif

[DURAMONSTER]

Dam I am glad somebody asked that. Me and my wife were sitting here trying to figure out what LOF meant also, then I scrolled down and there it was. Thanx.

[ram/tx]

Me Too. :eek: I thought I was missing some maintenance schedule thing on my truck. :rolleyes:

[chuntag95]

Laughing On Floor was what popped into my head first, but I got it later. Only killed half a dozen brain cells to do it too! :D

[Lonewolf867]

Thanks guys...I don't feel sooo bad now!!
I will remember that one!! Have to make a few buddies scratch their heads on that one.. :D :D

[dmaxalliTech]

Originally posted by chuntag95:
Why change the super coolant at 75k? Is that just a better safe than sorry? Would you go back red or green? Better safe then sorry, Can go green if you want, just make sure you flush it good before switching.

[cowboywildbill]

I think I read in a previous post that the red stuff (dexcool) was the culprit in eating head gaskets. Is there any truth to this, and if so maybe the switch to green would be safer. And a can of tdk or whatever the stuff is that keeps the liners wet so they won't get a hot spot.

[jbplock]

What is the best way to flush the Dmax cooling system? With my 6.5 I used to do an annual flush with distilled water (I know :rolleyes: ... I'm ultra-anal ). I would drain, refill with distilled water ($0.52/gal at Wal-Mart) and then take a short trip to warm the engine. I repeated this three times until I had just about 100% water in the engine. I would then drain one more time and top off with pure DexCool. The 6.5 would drain half the coolant so the ratio after the final fill was perfect at 50/50. There was also a bleeder on top of the coolant crossover to remove air.

Eric, Would process work for the Dmax?

[MadDuraMax]

"Better safe than sorry", is the reason for any accelerated maintenance schedule. Sure I've spent more than my fair share of time in GM (and other)assembly plants. Sure the quality control is better now than it ever been and sure we all know what it's like to go to work on a hot muggy Friday when we'd rather be soe where else.

Better safe than sorry...you bet, 500 miles on all critical fluids, check the torque on every screw, nut and bolt I could get to. Find potential problems on my GMC...you bet, but also on F*rds and d#dge's I've owned.

Hey it's your $45k+/-, sure you can go to the dealer and be without your truck more days or more for warranttee work. Better safe than sorry, you be the judge.

Mark

[TANKFULL]

Hi guys-
Great site. Lots of info. I talked to the service manager at the GM dealership That I just bought my truck from. He is advising me to wait and have my first LOF at 3,000 miles. He says this is necessary because there is a break-in conditioner in the oil that That needs to be in the the engine for that amount of time for proper engine break in. I would appreciate any feed back on his statement.
Thanks,
Walter

[FirstDiesel]

Doubt it.

That thinking is very old school.

[dmaxalliTech]

Originally posted by TANKFULL:
Hi guys-
Great site. Lots of info. I talked to the service manager at the GM dealership That I just bought my truck from. He is advising me to wait and have my first LOF at 3,000 miles. He says this is necessary because there is a break-in conditioner in the oil that That needs to be in the the engine for that amount of time for proper engine break in. I would appreciate any feed back on his statement.
Thanks,
Walter :rolleyes: :rolleyes:

[dmaxalliTech]

Originally posted by jbplock:
What is the best way to flush the Dmax cooling system? With my 6.5 I used to do an annual flush with distilled water (I know :rolleyes: ... I'm ultra-anal ). I would drain, refill with distilled water ($0.52/gal at Wal-Mart) and then take a short trip to warm the engine. I repeated this three times until I had just about 100% water in the engine. I would then drain one more time and top off with pure DexCool. The 6.5 would drain half the coolant so the ratio after the final fill was perfect at 50/50. There was also a bleeder on top of the coolant crossover to remove air.

Eric, Would process work for the Dmax? You gotta lot of time on your hands dont you Bill? :D

The above mentioned way would work, however, I dont like to work that hard. I would simply remove the petcock, remove both block plugs(on on each side) and let her drain, shove a hose in the coolant bottle and let her run until you get clear water from radiator, remove heater hose and shove the hose init until you get clear water from the block, then flush the heater core, apply some light airpressure to blow out as much as possible then fill er up. Your way is good too. I would use a quality flush treatment to loosen up any crap that is sticking inside of things.

[jbplock]

Thanks Eric! I'll look fo the block drain plugs. Your method sounds like a much better way to drain. :D

[Cliffee]

I would stick to GM's reccomendations except for the Fuel Filter. I recently had a rather long discussion with the head tech at Perkins Diesel here in AZ and he has seen all to many cases of the 15k change way too long. He strongly reccomended 10k-12.5k changes. Unless of course you were smart enough to add a pre oem filter.