Chevy and GMC Duramax Diesel Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
Hi all, Just made the switch to Diesel engine from long time gas user. Bought a 2020 Silverado high country and I’m loving it so far. Just curious to see what the major differences are with routine maintenance between gas and diesel. Hoping I don’t accidentally put gas in the tank after 25 years of using gas. And tips would be helpful.
 

·
Premium Member
Joined
·
2,176 Posts
Welcome aboard and congrats on your truck.
 

·
Premium Member
Joined
·
385 Posts
Keep up with air and fuel filter changes. Use good quality fuel and def. Other than that, pretty much the same as a gas engine as far as general maintenance goes.

Great engine and truck. Congrats. 🍻
 

·
Registered
Joined
·
208 Posts
Definitely fill with fuel where they sell lots of diesel.
 

·
Premium Member
Joined
·
34 Posts
Congrats on your new Duramax.
Even though you have a 'new' truck, I'd recommend checking all your fluid levels. I bought my new to me '15 3500HD in January and changed all the fluids. According to the car fax, all previous service was done at a local dealer. When i checked the rear diff, it required 20 oz of gear oil to bring it up to full.
Just saying you probably should check it over so you know what's what.
 

·
Premium Member
Joined
·
4,649 Posts
Congrats on your new Duramax.
Even though you have a 'new' truck, I'd recommend checking all your fluid levels. I bought my new to me '15 3500HD in January and changed all the fluids. According to the car fax, all previous service was done at a local dealer. When i checked the rear diff, it required 20 oz of gear oil to bring it up to full.
Just saying you probably should check it over so you know what's what.
Im betting you filled the differential til it just ran out the fill hole, didn't you?

Your truck was actually correctly serviced being that low. It should be run about 1/2 Qt (16 oz) below that fill hole.

You won't notice any problems until and unless the vent tube for the differential gets plugged. Then it will blow the excess oil out the axle seals onto your rear brakes.

Changing all the fluids in a New To Me truck is a very good idea if you do not know the service history. Here are some other good ideas:

 
  • Like
Reactions: ChevyTech77

·
Premium Member
Joined
·
385 Posts
Im betting you filled the differential til it just ran out the fill hole, didn't you?

Your truck was actually correctly serviced being that low. It should be run about 1/2 Qt (16 oz) below that fill hole.

You won't notice any problems until and unless the vent tube for the differential gets plugged. Then it will blow the excess oil out the axle seals onto your rear brakes.

Changing all the fluids in a New To Me truck is a very good idea if you do not know the service history. Here are some other good ideas:

Beat me to it. It’s been this way for 20ish years now, on almost all GM axles. It won’t just do anything bad when the vent gets plugged. Too high of a fluid level will cause excessive foaming of the fluid which then leads to incorrect lubrication of the axle. I use a 90 degree pick that I have that is perfect for verification of the fluid level in these axles.
 

·
Premium Member
Joined
·
4,649 Posts
Beat me to it. It’s been this way for 20ish years now, on almost all GM axles. It won’t just do anything bad when the vent gets plugged. Too high of a fluid level will cause excessive foaming of the fluid which then leads to incorrect lubrication of the axle. I use a 90 degree pick that I have that is perfect for verification of the fluid level in these axles.
I buy Mobile 1 lube in quart containers. It will hold 4 quarts, so I put in 3 quarts plus 1/2 of the 4th. Seems to work well and easy for my old brain to manage.
 
  • Like
Reactions: ChevyTech77

·
Premium Member
Joined
·
34 Posts
Well this is news to my old brain. Have never read of this, but I'll definitely check the owners manual. I understand the foaming concept and how that is bad for any lubrication application.
Has GM published a service bulletin on this?
 

·
Premium Member
Joined
·
385 Posts
Well this is news to my old brain. Have never read of this, but I'll definitely check the owners manual. I understand the foaming concept and how that is bad for any lubrication application.
Has GM published a service bulletin on this?
It’s been dictated in GM service information for years. 17-21 mm below the fill plug hole, for an 11.5” axle. Hell, the 1/2 ton rear axle (8.6”) is allowed up to 40 mm below the check plug hole.

Some people just bend a pipe cleaner or even a piece of wire to use as a “dipstick” to make sure the level is correct.
 
1 - 10 of 10 Posts
Top