Transmission Service?
I have a 2013 GMC Sierra 2500HD 2WD with 3.73 rear. 32K miles with 20K of that towing a 6K (loaded) TT. I carefully monitor trans temps when towing and it runs in the 145 to 170 degree range almost al...
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I believe that your truck uses DexVI which is a synthetic fluid. With the change to DexVI fluid interval changes were extended. As long as you are watching temps and they are ok, I'd go with the severe service change.
And, even if I wasn't in the severe service category, I'd still change it at the severe service interval.
And, for peace of mind, send a sample of the fluid at the severe service off to blackstone labs for analysis. I suspect it will come back that the fluid was in very good shape and you are ok with that service interval.
I've done that on four vehicles with those results, two of which see heavy towing use, and on the same vehicle, the 7500-10K for oil change and in every case the TBN is still high, contamination very low and indications that the change interval is conservative.
FWIW, it's interesting that the majority of mfg either don't list, or have a very long interval between brake fluid flush. IMHO a very bad idea. brake fluid absorbs water easily, leads to brake fade and other issues. That's one area where I go with every 2 years and use DOT4+ fluids rather than the commonly recomended DOT3.
And, even if I wasn't in the severe service category, I'd still change it at the severe service interval.
And, for peace of mind, send a sample of the fluid at the severe service off to blackstone labs for analysis. I suspect it will come back that the fluid was in very good shape and you are ok with that service interval.
I've done that on four vehicles with those results, two of which see heavy towing use, and on the same vehicle, the 7500-10K for oil change and in every case the TBN is still high, contamination very low and indications that the change interval is conservative.
FWIW, it's interesting that the majority of mfg either don't list, or have a very long interval between brake fluid flush. IMHO a very bad idea. brake fluid absorbs water easily, leads to brake fade and other issues. That's one area where I go with every 2 years and use DOT4+ fluids rather than the commonly recomended DOT3.
