Could 3.21 or lower numerical ratio gears work with CRD? What options are in the computer for tire sizes and gear ratios? How would this effect shift points? What front differential does the '08 Liberty use? Those questions asked The CRD seems to be cruising at an RPM higher than a diesel should for optimum fuel economy. I am open to all thoughts, even the negative ones.
Lewis

_________________
Mail Rated 2005 Red CRD Sport with large rectangular hole in top right behind the EVIC and above the heated leather seats.
2004 Jetta TDI

As of right now, you're limitied to the stock 3.73 or you can change them to 4.10 like the cool kids.

_________________
2006 CRD http://www.UtahPowderCoatings.com/ http://www.gorecon.com/ I'm kind of a big deal.
RL rear bumper, ARB front bumper, Mile Marker winch, Power Tank, Skids by Mopar & Skid Row, RL Super Skink Sliders, 235/85R16 MTR, Air Flow Snorkel, DTT, 4.10 gears, Frankenlift II, Katskin leather, JL Audio stereo, Rosen video.

That is going the wrong way. I know exactly what he is asking, and I FULLY believe the CRD can support a LOT lower RPM usage than the design fools at Mopar have chosen for us.

The cool kids dig a high reving engine.

_________________
2006 CRD http://www.UtahPowderCoatings.com/ http://www.gorecon.com/ I'm kind of a big deal.
RL rear bumper, ARB front bumper, Mile Marker winch, Power Tank, Skids by Mopar & Skid Row, RL Super Skink Sliders, 235/85R16 MTR, Air Flow Snorkel, DTT, 4.10 gears, Frankenlift II, Katskin leather, JL Audio stereo, Rosen video.

No, but you could go with 3.55s

_________________
http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

Would those be the cool kids that enjoy selling engines that they have designed to be out-of-spec to the engine manufacturers' original design limits?

Because that would be Ford. International told them "Don't spin this faster than 3500 rpm" which would have meant that Ford would have gotten bone crushing torque, but would have needed to pony up for more and better gears. Instead, they decided to stick with ~3.73 rear ends and only 4 gears... And BARELY any overdrive to speak of. Spin it faster, it's cheaper for Ford, and who gives two rips about that economy thing.

"But but but they now have big HP numbers! That makes our willys bigger!" says the morons at Ford. Big surprise, International told them to go fook themselves when the engines started failing right and left from being over-revved.

Obviously, Mopar and GM behave the same way. It's the same lack of logic that allowed everyone (EXCEPT the Asians) to sell cars without a transmission drain pan, and GM to ask the question "Why do they need more than two gears anyway?" Translation: we build stinky poo, they'll buy it anyway.

Dude...UR so uncool!

My 4.10 gears plus my Edge EZ module smoke it up yo!

But seriously....no 3.21 gears for you. And Ford does not impact our lives.

Some of us run bigger tires and go off road and tow lots so the 4.10 gears are pretty sexual compared to the stock 3.73. The stockers could not keep up with The Rockies and 32" tires

_________________
2006 CRD http://www.UtahPowderCoatings.com/ http://www.gorecon.com/ I'm kind of a big deal.
RL rear bumper, ARB front bumper, Mile Marker winch, Power Tank, Skids by Mopar & Skid Row, RL Super Skink Sliders, 235/85R16 MTR, Air Flow Snorkel, DTT, 4.10 gears, Frankenlift II, Katskin leather, JL Audio stereo, Rosen video.

That may be true... But what mountain ranges are you finding in Ft Lauderdale, FLORIDA?

My house is in Boca. Don't think I don't know that the ONLY hill worth talking about is Mt Trashmore. hehehehehe

Yeah - didn't the 4:10's get put in after moving to Florida? -- have they seen the Rockies yet?

_________________
2005 CRD
stuff
Skeptic quod gratis asseritur, gratis negatur

That would be the same thing if you went to 3.55's or 3.21's,out of specs for a auto tranny.

Hey a Detroit 8V92TA turning 8500rpms sounds cool ,handled that rpm with ease for over 45min,40 of them running just on it's own engine oil(fuel lines cut) till it started on fire(valve covers where off,replaced injectors and some dumb idiot messed with the buffer switch)till the fire department force fed it water through the turbo for 5 min before it hydrolocked and cracked the block in 4 pieces.

I also would like to let it run a lower rpms, but it's probably like the vw's, when I had a tdi asked about lower gearing for mileage, was told that the tdi had to run at the higher rpm for emission reasons, so I figure the crd is the same.
A two speed rear end would be just neat.

_________________
JEEP naked it adds color to your cheeks.

That sounds about right, considering the stupidity of the newest emission "reduction" ideas. Hmm, let's reduce emissions by burning even MORE of the stuff that produces the emissions in the first place. The regeneration systems inject raw fuel on the EXHAUST stroke (TOTALLY wasting all that fuel) as a means of raising the EGT.

Does this seem stupid to anyone else?

What that VW answer proves is not that the engine or transmission can't handle the lower RPM (which it OBVIOUSLY can, it does it from every single stoplight) but that the EPA doesn't WANT less fuel burned. Burning less fuel will INSTANTLY reduce the emissions by that same percentage, all the time and forever.

I'm hearing similar arguments from even the ultra-greenie crowd that wants to build electric vehicles. People have asked the question: "Why not power an electric car with a small or medium size generator, instead of dead-weight batteries?" "Because generators don't have any of the emissions control equipment of larger car engines" is the answer.

What I see as the hidden answer: "Because a generator that burns ONE gallon per HOUR all the time would mean a car getting 80 mpg at 80mph, 60mpg at 60mph... And it is completely impossible to develop ANY emission controls for a small engine that burns so little fuel. It really needs to burn 10 gallons per hour or more."

The fallacy there is that is is OF COURSE possible to develop emission controls for a small engine. I'm sure that a tiny catalytic converter could be developed with an ELECTRIC heater (instead of a raw fuel heater) just like have been used for 20 years on cars. But the emissions output of such a small engine... Do they REALLY compare with the likes of a Hummer or an Excursion?

The people who make those decisions have either had lobotomies, or been completely bought off. There isn't any other LOGICAL conclusion.

I think 3.55's should be an option in the computer(I do not know what options are available), but only 5% change in rpm. For Jeep to have given the CRD the same gears as the 3.7 gasser(patooie!, with cudos to gmctd) shows a real lack of understanding of the diesel torque range. I would like to be able to shift out of OD on a long hill pulling a load and keep the rpms down at 65 or 70 mph. How would changing the gearing change the shift point speeds?
Lewis

_________________
Mail Rated 2005 Red CRD Sport with large rectangular hole in top right behind the EVIC and above the heated leather seats.
2004 Jetta TDI

Everything about CRD's indicates this was a 'quick and dirty' project to test feasibility - with as many off the shelf parts as possible - with minimal design resources - minimal disruptions to standard production
i.e. plug in a diesel and see if people will buy it. There was no attempt to understand or optimize for the diesel.

That said, the 3.55's were an option on some Libertys - so they should fit (although not common, so probably not easy to find) - you can get some of the effect by taller tires - however that increases the rotating mass and makes bad aerodynamics worse so depending on your driving - it could easily make things worse.

_________________
2005 CRD
stuff
Skeptic quod gratis asseritur, gratis negatur

A lot of the people who make these decisions have slowly risen through the ranks in the automotive companies. They've had free cars, gas, and service for so long they've completely forgotten the cost and time of maintaining a vehicle. And the problems that rise from poor design / maintenance (walking).

3.55 gears are not only available, but they are factory in some KJ's. I think that's the axle ratio in the manual transmissioned gas and CRD.

_________________
2005 CRD Limited Flame Red w/ Renegade rock rails & light bar, AirLift 1000. 225/75R16 MT/R's on cheap black steel wheels, dual MOPAR subwoofers, Ipod kit & seat covers, Samco hoses - totaled and gone. 2008 WK Laredo 3.0L diesel - AirLift 1000, wife won't let me mess with it much. 2013 JK Sahara on order.

3.21 gears are available in the 08 Liberty. I know the front diff in the 08 is a Dana 30/186mm the rear is a 8.25 Chrysler. The question is will they bolt up in a CRD and can they be interagrated into the computer?

_________________
Mail Rated 2005 Red CRD Sport with large rectangular hole in top right behind the EVIC and above the heated leather seats.
2004 Jetta TDI

Not just on our CRD's - go to a Dodge Cummins forum and read some of the gripes about the available gear choices. They used to have choices available down into the 3.40's and 3.20's, and the complaints have been many since Chrysler eliminated those choices.

Basically, numerically lower (ie, taller) gearing is better for unloaded fuel mileage and high speed driving, while numerically higher (ie, lower) gearing is preferred for towing heavy loads - even a diesel can be ran too low in the rpm range depending on conditions.

For our one-off U.S. market experiment CRD, 3.73's seems to have been a compromise between fuel economy and towing ability, saving Chrysler the time and expense of offering more than one gear ratio.

A few months back, Ranger1 informed me that Chrysler was actually offering 3.21 gearing in the '08 Liberty and Patriot as well if I remember correctly.

I did a search of the aftermarket options available at the time. Going by memory, you can get replacement gear sets for both the front and rear axles in 3.55. And if you were willing to convert the beast into strictly a 2WD unit, you could go as low as 3.08 for the rear axle.

My old '87 MB has a 2.65 rear end, but only 1:1 in 4th with the old-fashioned auto tranny in it. I'd give my eye teeth for a 5th gear OD in it, it'd be able to push close to 40 mpg on the interstate. Driving to work and keeping it at 55 mph and a little over 2000 rpm, it regularly exceeds 35 mpg. I went from 195/65R15's to 205/70R15's on it, 5% difference in diameter - speedo low by 1 mph for every 20, and odometer low by 1 mile for every 20. For doing 55 mph, I split the difference between 50 and 55 on the speedo, engine turning a couple hundred rpm slower - as long as I remember to do this, it does make a noticeable difference in fuel economy.

_________________
Mitchell Oates
'87 MB 300D Diamond Blue Metallic
'87 MB 300D - R.I.P. 12/08
'05 Sport CRD Stone White
Provent CCV Filter/AT2525 Muffler
Stanadyne 30 u/Cat 2 u Fuel Filters
Fumoto Drain/Fleetguard LF3487 Oil filter
V6 Airbox/Amsoil EAA Air Filter
Suncoast TC/Shift Kit/Aux Cooler
Kennedy Lift Pump/Return Fuel Cooler

Rear axle shouldn't be a problem, ours is a 8.25 Corporate as well. Can't remember exactly what we have for a front axle, but given their drive for cost savings the last few years, I'd be willing to bet it's the same.

As for the computer, given the availability of aftermarket reprogrammers for those that like to bolt on lifts and large tires, shouldn't be much of a problem. At that, should be a simple matter for the gents at Inmotion to come up with a tweak to their programming to cover it.

_________________
Mitchell Oates
'87 MB 300D Diamond Blue Metallic
'87 MB 300D - R.I.P. 12/08
'05 Sport CRD Stone White
Provent CCV Filter/AT2525 Muffler
Stanadyne 30 u/Cat 2 u Fuel Filters
Fumoto Drain/Fleetguard LF3487 Oil filter
V6 Airbox/Amsoil EAA Air Filter
Suncoast TC/Shift Kit/Aux Cooler
Kennedy Lift Pump/Return Fuel Cooler

Great input. I am pretty sure the '08 Liberty is a Dana 30a and should be able to bolt up OK. I will check with Inmotion about gearing options. I have gotten tired of asking questions of service reps. Now to watch the junkyards for '08 Libbys.

_________________
Mail Rated 2005 Red CRD Sport with large rectangular hole in top right behind the EVIC and above the heated leather seats.
2004 Jetta TDI

Inmotion can't help you.

The speedometer input goes into the BCM, the BCM broadcasts the data on the PCI bus.

To re-calibrate the speedo someone with a DRBII needs to connect to the PCI bus, and change the configuration for revs in BOTH the BCM and ABS modules, doing only one will not work, both need to be changed.

The ECU has nothing to do with the speedo - it is merely a slave to the master(s).

_________________
http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic