hatzie
I'm Awesome
Machine flushing is actually asking for trouble.
BTW I don't classify swapping the whole ATF oil charge by putting the trans cooler return line in a bucket to catch the nasty oil being pushed out by the fresh ATF you continually add to the pan as a flush. That's a 100% ATF change.
Drop the pan once and change the strainer. Add a Magnefine filter to the return fluid line from the coolers to clean things up. Then drain the pan without dropping it at shorter intervals... 2-3 oil changes and swap the fluid. I change my first Magnefine on a used rig at 1,000 miles and the next ones every 5,000 miles with the engine oil. The ATF is usually cleaner after the 2nd Magnefine than I used to get on two pan drains.
The drag you feel may actually be a setup issue in the PCM. Your truck, if it's like most 3/4 ton GM trucks, came with 30.5" 245/75R16 tires. You need to change the parameters for the Transmission and Engine controls to reflect the 32.7" 285/70R17 tires you're running. Those 33s throw off the speedometer so it's showing a slower than actual speed but they also have your PCM pulling parameters from the wrong areas of the fuel, shift, and transmission pressure maps. You will perceive this as drag.
It's amazing what re-calibrating the PCM tire size will do to the driveability. If I hadn't just experienced the fairly extreme difference in driveability on my 2005 2500HD with just a 1.2" outside diameter calibration change between the PCM calibrated for the original 30.5" tires and the new 31.7" tires I wouldn't believe it.
My 2000 GMC C2500 has a 5 speed stick so I really don't feel much drag... Just went from the stock 245 to 265 tires on the same wheels and my tuner software won't touch the 6.5L ECM.
BTW I don't classify swapping the whole ATF oil charge by putting the trans cooler return line in a bucket to catch the nasty oil being pushed out by the fresh ATF you continually add to the pan as a flush. That's a 100% ATF change.
Drop the pan once and change the strainer. Add a Magnefine filter to the return fluid line from the coolers to clean things up. Then drain the pan without dropping it at shorter intervals... 2-3 oil changes and swap the fluid. I change my first Magnefine on a used rig at 1,000 miles and the next ones every 5,000 miles with the engine oil. The ATF is usually cleaner after the 2nd Magnefine than I used to get on two pan drains.
Yeah i didn't buy the 285s for the stability, I bought it for the extra off road capability and look, but I can feel the excess drag over 265s, which i had at one point. My pan already has a drain plug, actually, but with 251k on it I don't really want to touch it.
And luckily, all of the driving I'd do is between East Texas and Kansas, so just rolling hills. The trans temp gauge is a great idea actually.
The drag you feel may actually be a setup issue in the PCM. Your truck, if it's like most 3/4 ton GM trucks, came with 30.5" 245/75R16 tires. You need to change the parameters for the Transmission and Engine controls to reflect the 32.7" 285/70R17 tires you're running. Those 33s throw off the speedometer so it's showing a slower than actual speed but they also have your PCM pulling parameters from the wrong areas of the fuel, shift, and transmission pressure maps. You will perceive this as drag.
It's amazing what re-calibrating the PCM tire size will do to the driveability. If I hadn't just experienced the fairly extreme difference in driveability on my 2005 2500HD with just a 1.2" outside diameter calibration change between the PCM calibrated for the original 30.5" tires and the new 31.7" tires I wouldn't believe it.
My 2000 GMC C2500 has a 5 speed stick so I really don't feel much drag... Just went from the stock 245 to 265 tires on the same wheels and my tuner software won't touch the 6.5L ECM.
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