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Old 11-08-2019, 03:54 PM   #18 (permalink)
gumby79
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Join Date: Dec 2014
Location: Butte, Montana
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little jona - '91 Dodge D 250 first gen cummins LE
Team Streamliner
90 day: 23.4 mpg (US)

Little Jona airo modded - '91 Dodge RAM 3/4 TON D 250 2×4 AUTO
Pickups
Team Cummins
90 day: 18.5 mpg (US)

The Salted Hound Jenny. - '87 Dodge Ram 50/D-50 5sp 4X4
90 day: 20.24 mpg (US)

Jona Allison aero - '91 Dodge Ram D-250 Le
90 day: 20.76 mpg (US)
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Without doing the research on your specific transmission no one can answer the questions about your specific unit. You're 7000 miles and no issues showing up sounds like the trial-and-error method has shown you to be on the right track. I gave the examples of my Allison Transmission because it has both configurations available torq converter locked and unlocked shifting

GM Chevy use the unlocked+pressure control. Medium-duty Freightliner Mercedes and other such medium and heavy-duty manufacturers use a locked shift pattern from 2nd gear through 6th Gear by controlling line pressure, engagement, and release rates on three separate solenoids to adjust shift firmness, and prevent RPM flares AKA slipping the clutchs

Bottom line If your transmission is anything like mine, not being able to control the line pressure + locked shifting may be problematic trial and error will rule that out by surviving thousands of miles, or confirm that it is a problem by wetting the bed in short order. You reported no additional abrasiveness to the shifts having bypass the pressure control and manually locking the torque converter and that it is a very small sample size. Get a bigger a sample, then report back. Blackstone fluid analysis is about 20 bucks if it's wet they can test it. Cheap insurance and a way to test it without making it fully wet the bed

I apologize I evidently came off negative. I do not have experience with your unit I do however have experience with medium light-duty applications. As far as your experiment has been explained sounds like you're on the right track and things are looking good. And it sounds like it's time to move on to phase two of testing locked + no pressure control. I would run the experiment the other direction however locked with pressure control monitoring the tcm's pressure readings to see if it is adjusting to compensate for a locked shift then run a phase 3 disabling bypassing the pressure control system
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1st gen cummins 91.5 dodge d250 ,HX35W/12/6 QSV
ehxsost manafulld wrap, Aero Tonto
best tank: distance 649gps mi 24.04 mpg 27.011usg
Best mpg : 31.32mpg 100mi 3.193 USG 5/2/20


Former
'83 GMC S-15 Jimmy 2door 2wd O/D auto 3.73R&P
'79 Chevy K20 4X4 350ci 400hp msd custom th400 /np205. 7.5-new 14mpg modded befor modding was a thing
87' Hyundai Excel
83 ranger w/87 2.9 L FI2wd auto 18mpg on the floor
04 Mitsubishi Gallant 2.4L auto 26mpg
06 Subaru Forrester XT(WRX PACKAGE) MT AWD Turbocharged 18 plying dirty best of 26mpg@70mph
95Chevy Blazer 4x4 auto 14-18mpg
04 Chevy Blazer 4x4 auto 16-22mpg


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EcoCivic (11-08-2019), Piotrsko (11-09-2019)