After a lot of debate, I finally gave in and got F-37 done about 2 months/ 1500 miles ago. The results:

1 - MPG: Went up a solid 1.5-2 MPG. I have the gas receipts and a log all the way back to brand new, and had a hard time breaking 18-19 in 99% stop and go traffic. Now its consistantly 20-21. Part of that may be related to the switch over from winter blend diesel, although last year the switch didn't impact MPG at all so???

2 - drivability: I kept track of RPM's at various points of the daily drive, what gear it climbs the hill to our neighborhood in, etc, and haven't noticed any change in gear or RPM. My wife thinks it shifts smoother, but thats the only difference.

My theory: I had the reflash done (can't recall the #) last fall that made the computer EPA compliant and was supposed to improve drivability. I wonder if that flash had already altered the shift points/ torque management and it just wasn't disclosed? Then F37 wouldn't have changed anything.

Either way, no leaks and no problems so far with this 'customer satisfaction notice'.

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2005 Limited CRD

I believe you're correct about the shift points being changed earlier (F31 ??). My shift points change dramatically at that time. I have not yet done the F37 but the car shifts like others have reported.

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2006 Libery Sport CRD, Lt Kakhi, nicely equipped
*****GDE Hot Tune at 38,879 miles
*****Stock TC.....for the time being!!

My understanding is the F31 programming is virtually the same as F37.

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06 CRD "Smogger" Dark Khaki, Sport, 22C, tow package, hitch, 6 disc and slightly addictive SIRIUS sat radio.
82 CJ-8 04 Light Khaki, rebuilt 4.0L w/FI on the stand and ready to go in.

Had the flash done about a month ago. My results seem different. I was getting 22+ MPG before around town. Now I am lucky to get even 20. Anyone have any suggestions. I have 24,000 miles.

Same happened to us. Were were getting great milage, not it's in the crapper.

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2005 Unlimited (LJ) Rubicon w/ 5.5" of total lift
Flat Fenders made by http://www.jpfaboffroad.com/

"Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin, 1759

My gas mileage tanked hard after F37. Easily lost 2-3 mpg since.

Mines back in the shop for some unknown rattle coming from the engine. Going to go 100+ days in the shop, whooo hoooo. What a piece of @#@# this thing is. I cant say enough what a disappointment this vehicle has been.

Chrysler should be sued out of business for releasing a such a dud. Sorry but I cannot hide my disappointment.

Yep, my mileage has gone down a couple points as well. Used to get 20 towing my trailer, after F37 it's down to 18 (even w/ the ORM). Also, I get a really hard shift into 3rd when gently accelerating. Like they're REALLY retarding the engine during the shift. No clunking noise, just feels like they shut off fuel for a full second during the shift and causes the jeep to lurch.

Not to mention my tranny was 4 quarts low when I got it back from the dealer. May use that along w/ the above to go and complain for them to try and fix it.

I'm at 28K miles total and plan to get an InMotion ECOTUNE once the warranty is up. Hopefully that'll restore my mileage.

Figured F37 would be a good idea for the free, brand new TC. Maybe it was a mistake...

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Chris
Current:
2007 Steel Blue Metallic Grand Cherokee CRD Limited
GDE Eco Tune and DPF delete
CB Engineering DPF delete pipe
EHM

Past (sold to Mountainman):
2005 Patriot Blue Liberty CRD Limited