Maintenance Interval - Transfer Case Fluid Change

[mopac]

I'm looking through the 2018 Owner's Manual for my 2018 Silverado 1500 LT 4x4 (NOT Z71) and there are 2 different maintenance intervals for changing the transfer case fluid.  With a GVW under 8,600 lbs it should be done every 97,500 miles.  With a GVW over 8,600 lbs the change interval goes to every 45,000 miles.     I guess the cover of the owner's manual DOES just say "Silverado" and not 1500, as I didn't think any 1500 had a GVW over 8,600 lbs.    Assuming they are referring to the GVWR (Gross Vehicle Weight RATING) which for my vehicle is listed at 7,200 lbs.  

 

Are the fluids really THAT good now?  97,500 miles?  I plan to drive this truck until it drops so I guess I'll find out.  And maybe they are that good now.  After all the manual (on Page 446) also says I can go for 150,000 miles without changing the cooling system fluid.  (Would almost seem demeaning to call the stuff just "antifreeze" these days if it lasts THAT long.)  

Silverado 2018 Owners Manual.pdf

[Mike GMC]

They are not that good and if you plan to make the truck last as long as possible, you will not try to run them that long.  I can't tell you what the "right" interval is, but I can tell you I have already changed all the fluids in mine and it only has 39k on it.  The t-case fluid looked particularly nasty.  The diffs weren't too bad, but looked like they were ready.  The coolant was definitely ready.  The trans fluid is still clean looking and slightly sweet smelling so it has not been changed yet.  Go figure.

[J-man67]

I'm at 150k and just changed my transfer case fluid. It looked OK. I tow/haul heavy frequently and I was never concerned. Last truck had more miles, harder life, and I never changed the fluid in that. Not sure how many miles on it now but I sold it like 4 years ago and just saw it driving down the road the other day. Don't do a ton of 4x4 though. Just inclement weather and rare off roading.

 

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[Black02Silverado]

For the amount of fluid that the T case takes and how easy it is to change why not change it out every 50k?  Not like it is going to break the bank and like I said, it is super easy to do. 

 

Take care of your vehicle and it will take care of you.  I know the manual states a longer interval but in reality one doesn't drive "normal" service much anymore in my book.

 

The coolant change out is 150k miles or five years which ever comes first.  We will hit the time factor on that before we hit the mileage at only putting 22k miles on a year.

[mopac]

37 minutes ago, Mike GMC said:

The trans fluid is still clean looking and slightly sweet smelling so it has not been changed yet.  Go figure.

Funny, now that I'm looking I don't see that the maintenance schedule EVER says ANYTHING about changing the transmission fluid.  I guess it's "forever fluid" in their book.

[btj_z71]

I changed mine at around 58k.  The fluid was not that bad, but the number of metal shavings caught by the drain plug was surprising.  Seems most others had about the same ferrous material on theirs as I did though.  

 

The front differential had the worst fluid in it.  It looked like coffee with some cream it, light brown/brown, thick and gross.  The rear diff had the best looking fluid, almost looked new even at 58k.  Anyways, I replaced fluids in the front and rear differentials and the transfer case all with Amsoil.  Best stuff out there.

[Mike GMC]

Yep, diffs and t-case are easy, I also use Amsoil products in everything.

[William Thompson]

Change the fluid early and they still should have lubricity, and less metal in the fluid, by the change interval the fluid is worn out, and has little metal debris floating in it, and on the magnetic plug, 30-50k Acdelco Dexron VI transmission fluid, for the transfer case and the same stuff for the transmission, just a preference because its what came in the truck. Mine is a 14 Gmc sierra 4x4 Slt 5.3, Z71. I changed out the dexcool at about 145,000. Used the Acdelco concentrated and mixed 50/50 water, after flushing with distilled water. Probably could have done that sooner as it looked bad, and had some minor electrolysis. The front and rear diffs were easy on mine as well, I did the rear around 150,000 and the front sooner around 120-130,000. I replaced the brake fluid around 120,000 or so and it needed changing, it was very dark, when new fluid is almost clear. 

[pronstar]

My new to me 2015 truck has 30k on it.

Just had tranny, t-case, diffs and brake fluid done. Oil was already changed by the selling dealer.

Just a habit I’m in when I buy a used vehicle - swap out the major fluids.

Coolant isn’t stressed like the other fluids so I’ll let that go another year. Which is still a year sooner than the manual recommends.


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[Colossus]

Transfer case every 30,000 miles along with front and rear diff.  Unless you drive it thru a lot of water, then do it sooner. 

[tyler.frost92]

changed mine at 30k. Still looked bright red, and ive used 4x4 off road quite a bit

[Zirdam1]

I bought my 2014 5.3 LTZ with 68k. It is now up to 75k and I just completed a full gear box service at the dealership. Front + Rear Diffs and the T-Case. Total cost was $343.64. The breakdown is $113.25 in parts and $230.39 in labor. I had every intention to do it myself but just have no time, got a new job. Anyhow, wanted to share what that cost is with everyone that is thinking about doing it at a dealer. I live in Montana. 

[typ0]

Unless you are driving in laboratory conditions I would use the severe duty maintenance schedule. The only difference I see between normal and severe schedules are the transfer case fluid changes. 

 

Normal

<8600lb      97.5k miles

>8600lb      45k miles

 

Severe

<8600lb      45k miles

>8600lb      22.5k miles

[Colossus]

Ditto on using the severe condition.  Unless you live in Florida and drive nice and easy. 

[Doublebase]

Personally I'd just change it out under the severe service interval or less (I'm a little anal and did mine at 26K miles and I drive that much in a year, so I'll just do it every year). But for all of the gloom and doom around here we hardly ever hear about rear end failures or transfer case failures...so that should tell you something...in the world of "these trucks are bad", you don't hear about these components failing. And you know there are people on here who beat the ever living tar out of these things.