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Warning, check fluid levels on new trucks


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My 2015 Denali 3500 HD has 2800 miles so I took it to my mechanic (nor dealer) for first break in PM. I changed oil/filter and lubed chassis. I took it to my mechanic because I personally I do not trust any GM dealer providing the free 2 yr service.

Good thing I did. The rear differential was low one quart gear oil and the transmission was low one quart. This is straight from the factory.

I am pretty confident my dealer would not have caught this as they certainly didn't check these things during the PDI.

If you haven't already checked all fluid levels on a new truck, but recommend that you do and don't trust that your dealership does/did just because they said so.

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Same thing with my 2013 1500. The rear diff was almost 2 pints low and the transfer case fluid looked horrible. I always change out all the drive train fluids/lubes within the first 3000 miles on all of my vehicles. My new 2015 2500HD will get the same treatment in the next few weeks. Quality control is certainly lacking at the factory, and it is down right criminal the way dealers will not completely check vehicles before turning them over to the buyer. I got sideways of my last dealer over this. Probably caused a potential buyer that overheard me chastise the dealer leave and go somewhere else. Two layers of quality control totally overlooked.

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Just about every single AAM rear axle (what's in your truck) has shipped one quart low on fluid.

 

I drop and refill all filters/fluids at 500 miles, I don't trust GM and also want the fluids out.

 

Dealers don't really check the vehicle over like they are supposed, they simply check the boxes, wash it, and hand the keys to the customer. Having said that my local hometown dealer has one guy that does this all day/everyday and I have seen him many times checking fluids in vehicles, I will put money on him checking every fluid in every vehicle that comes in, having said that I am SURE he is the only guy that actually PDI's anything!

Edited by SMiller
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  • 2 weeks later...

I was always trained that the correct level is when the oil just begins to run out the fill hole.

 

For rear differentials, according to GM, that method is wrong. The recommended level on many of these is not level with the fill plug. (if the OM is to be believed) From the 2015 manual for the rear ends:

 

. For all 4.3L and 5.3L 1500 Series applications, the proper level is 1.0 mm to 19.0 mm (0.04 in to 0.7 in) below the bottom of the fill hole, located on the rear axle. Add only enough fluid to reach the proper level.
. For 6.2L 1500 Series applications, the proper level is from 15 mm to 40 mm (0.6 in to 1.6 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.
. For all 6.0L 2500HD Series applications, the proper level is from 0 mm to 13 mm (0 to 0.5 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.
. For all 6.6L Duramax Diesel 2500HD Series applications and all 3500 Series applications, the proper level is from 17 mm to 21 mm (0.6 in to 0.8 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.
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Since these diffs are not done in gallons but quarts (pints), it is highly doubtful that the recommended level in any of those recommendations equates to a quart difference. It sure doesn't take a quart, in a rear diff that holds 6.3 pints.... just over 3 quarts. If the diff is a quart low, it is going to be substantially below the .5 in below the fill hole standard.

 

I haven't done my 2015 2500HD yet, but when I did my 2013 1500, I measured what I drained out of the rear diff and compared to what I needed to put in to bring it up to the recommended fill level. There was a two pint discrepancy. The factory fill was not near adequate. Doesn't surprise me a bit that Steve found his 3500 to be a quart low. When I get around to doing my new 2500 in the next few weeks, will see how it is for mine.

Edited by Cowpie
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  • 2 months later...

 

I was always trained that the correct level is when the oil just begins to run out the fill hole.

 

For rear differentials, according to GM, that method is wrong. The recommended level on many of these is not level with the fill plug. (if the OM is to be believed) From the 2015 manual for the rear ends:

 

. For all 4.3L and 5.3L 1500 Series applications, the proper level is 1.0 mm to 19.0 mm (0.04 in to 0.7 in) below the bottom of the fill hole, located on the rear axle. Add only enough fluid to reach the proper level.
. For 6.2L 1500 Series applications, the proper level is from 15 mm to 40 mm (0.6 in to 1.6 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.
. For all 6.0L 2500HD Series applications, the proper level is from 0 mm to 13 mm (0 to 0.5 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.
. For all 6.6L Duramax Diesel 2500HD Series applications and all 3500 Series applications, the proper level is from 17 mm to 21 mm (0.6 in to 0.8 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.

 

 

So how in the heck does someone fill to just 0.5in below the fill plug hole? No plus/minus range, exactly 0.500000 inch from the fill plug? Does the service manual provide some technique? Some special $$$ GM tool? Do I need a inspection camera to check? What do dealers do? I guess I could park front down on my driveway (light slope) and fill to the top, when the vehicle is level the fluid would be below the hole. Maybe a bent wire could be used to just the level? A little vacuum pump remove excess?

 

Okay, I'm sort of joking, sort of... I'm sure I will get a "Just fill the top and don't worry about it" response. :thumbs: But still, I would like to do it best I can.

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The manual clearly states bottom on fill hole on transfer, front diff, and rear diff on the 2500 6.0L gas. Only thing different is the Dmax 2500/3500 rear diff, .6-.8 below fill hole, which is easy to determine. Most folks have a knuckle on their pinky finger right after the fingernail. Hook that pinky finger in the fill hole at the first knuckle and check occasionally as you fill. Once the level reaches your finger, you are done. I know it is not some algorithmic formula complete with diagrams and charts or schematics, but it has worked for well over a century. Some things stand the test of time.

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The manual clearly states bottom on fill hole on transfer, front diff, and rear diff on the 2500 6.0L gas. Only thing different is the Dmax 2500/3500 rear diff, .6-.8 below fill hole, which is easy to determine. Most folks have a knuckle on their pinky finger right after the fingernail. Hook that pinky finger in the fill hole at the first knuckle and check occasionally as you fill. Once the level reaches your finger, you are done. I know it is not some algorithmic formula complete with diagrams and charts or schematics, but it has worked for well over a century. Some things stand the test of time.

Could also use an Allen wrench, hook it in to measure
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Regarding the fluid levels... When I did my 2015 2500 drivetrain fluids a few weeks ago at just over 3000 miles, the rear diff was a full 2 pints low. The front diff was below the minimum level, the transfer was fine. The magnetic plug on the transfer was already starting to get "hairy" from wear metals. Not as bad as the 2013 1500 I had. On that one, there was so much wear metal shavings that it looked like someone had stuck my cat's tail in a light socket. Either way, I am rock solidly behind changing out fluids early on. The 1500 and now the 2500 firmly put me in that camp. Now all I need to do is pack the front hubs and it will be all done.

Edited by Cowpie
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The manual clearly states bottom on fill hole on transfer, front diff, and rear diff on the 2500 6.0L gas. Only thing different is the Dmax 2500/3500 rear diff, .6-.8 below fill hole, which is easy to determine. Most folks have a knuckle on their pinky finger right after the fingernail. Hook that pinky finger in the fill hole at the first knuckle and check occasionally as you fill. Once the level reaches your finger, you are done. I know it is not some algorithmic formula complete with diagrams and charts or schematics, but it has worked for well over a century. Some things stand the test of time.

6.0 3500 gets the Duramax AAM 11.5 rear axle.

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That is true. That is why stated the 2500 6.0L gas is the one that all the levels are at the fill hole. I just didn't clarify in more detail about the 3500.

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I always check them on any new vehicle.

 

More than once I have seen it low.

 

Brought home my 2013 Traverse and found the DEXCOOL low in the radiator not the overflow.

 

So I topped it off the first day I owned it.

 

A few month later GM issued a recall on this very issue. The sent a load of them out like this.

 

Of course I just told them I toppped it up on day one and to just mark mine as done.

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