This is an intriguing idea and I'm trying to figure it out. The CRD is my first automatic so I don't know how to tell if the torque converter is locked. I've been watching it and it does seem if I creep up to 55 the engine settles out 200 RPM higher than if I speed up fast and the tranny shifts into OD at 55. Is this what you mean by locking it? How much difference does it make in the economy?

Jake

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05 crd sport - 110000 mi
one torque converter/front pump down
two egrs replaced
one rear control arm, sort of

http://www.jakemooremd.com .
http://www.coastalbendeye.com.

Ditto. I get less than spectacular mileage all the time. The best tank ever was 24.8 driving on the highway during vacation.

I just ran a test comparison on two full tanks.
In both cases the fuel appeared to be ULSD (no official test, but it smelled pretty )
I'm in Florida, with nice, warm, dense, sea level air.
90% of my daily commute (about 40 miles round trip) is on the higway.
The Jeep had 7,900 miles on it at the start of the test.

First Test:
39 psi (cold) in the OEM tires
Added a dose of PS for the cetane boost.
Accelerated moderately and drove consistently.
Used cruise to keep it in the 1800-2000 power band as much as possible on the highway.
Coasted on off ramps and coming to red lights as often as I had the opportunity
Result: 21.4 mpg.

Next Test:
35 psi (cold) in the OEM tires
Accelerated like cops were chasing me. Did as much unnecessary acceleration as possible.
Drove around with OD off. Cranked it up past 3500 rpm with OD turned off when getting on the highway, and then finally turning OD on.
Drove on the highway to the limit of the Liberty's cruise control and beyond. (and sometimes I was still being passed -- Florida drivers! .)
Avoided coasting to a stop.
Result: 20.2 mpg.

I gotta figure something is wrong with the Jeep. It seems the Jeep just wants to operate in a "least efficient" mode all the time. It has never had an engine or transmission related code on the computer or idiot lights come on the dash. ( And I was not driving with the parking brake set )

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Thanks,
Ken Jennings
2006 KJ Limited 4x4 CRD, Option Pkg G, Lt. Khaki, Built 1 Feb 2006
Tow Package for myself, EVIC TPM
Side Curtain Airbags for my daughter
http://www.kenjennings.cc/crd/dieselexp.html

I routinely get mid 20's to and from work and have seen 30+ on highway. Sweet spot seems to be around 60-65 mph for me. I keep the tach around 1800 rpm. I'm still on the stock tires inflated to 40psi. I've put 23K on the vehicle so far. I believe I have the latest ecm and tcm flash updates, but the only difference I saw after the flash was the elimination of the transmission shudder around 55-60.

I like to fill my tank all the way up the filler neck so I think I'm getting accurate gallons for my calculations. I always use 8 ounces of Power Service per tank.

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2005 CRD "Ol' Blue"
Red Ryder carbine-action, two hundred shot range model air rifle with a compass in the stock and this thing which tells time.
My build page- RL Komodo Rear and TJM Front Bumper, armored, lifted, JBA Steel D30, 4.10s and ARB air lockers.