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Old 01-09-2020, 05:11 PM   #40 (permalink)
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Join Date: Dec 2014
Location: Butte, Montana
Posts: 691

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 24 AUTO
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: 20.23 mpg (US)
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Trans temp?

With my 6sp(7 counting TC lockup) Allison, 145f to enter learning mode. Per the Trans Builder keep it above 145f to keep it alive and adjusting the shift trims for current conditions.

Dodge put out a TSB about transmission fluid viscosity issues. At -10 F the ATF+4 trans fluid congeals/ freezes in the air to liquid cooler mounted in the cooling stack, restricting flow through the cooler circuit causing the transmission to overheat.
I have not gotten a straight answer at what temp this is a problem with Allison fluid. Dodges fix was to bypass the air unit and just use the massave remote liquid the liquid unit bolted to the side of the block using a heater core circuit. And tell the customer to swap back and forth for towing in hot and solo in cold.

Final advice I implemented routing.
Stock is:


Industrial Allison standalone computer locks the TC@ 20mph ~1/2 way through 2nd. So no TC heat, it will(my Allison) run too cold and seldom be in learning mode especially in MT winter. So far single digits trans temp 161 F/ CT,171. Without pulling heat from the Cummins the Allison would not be happy. And the worst of winter is yet to come.

Find out what temp your TCM enables learning. That is the magic low temp, bottom line.
If it is all hydraulic mechanical so long as it's not overheated it doesn't care . However the TCM from the 46RH that came out did disable the electrohydraulic OD (.61/2.44 final) till the trans hit 45f ~1.5 mi @ -20F when pluged in CT ~60F

+1 on the user selectable raito and #of shifts available CVT shift patterns. I still dont get the point of a CVT with set shift raitos , especially it described here to match a normal automatic . Only thing I can come up with is too many complaints about people feeling like they're driving a snowmobile with three RPMs accelerating, cruising, and compression braking.
1st gen cummins 91.5 dodge d250 ,HX35W/12
ehxsost manafulld wrap, Aero Tonto
best tank: distance 649gps mi 24.04 mpg 27.011usg
Best mpg : 29.3mpg 97mi 3.311usg 7/27/16

'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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