GDE Trans Tune options

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Below is a link showing the GDE Fuel Economy Trans Tune shift schedule.

http://www.keepandshare.com/doc/2813701 ... m-19k?da=y

Here is a link showing the GDE Towing Trans Tune shift schedule.

http://www.keepandshare.com/doc/2813702 ... m-19k?da=y

The primary difference is the towing tune will hold 4th gear until 70mph (2280 engine rpm) and then upshift to 5th gear. Using 4th gear between 50-70mph while towing loads over 2500lb. is beneficial for holding gear while traversing hills and it also keeps the engine rpm in the most efficient torque zone to reduce the tendency for gear hunting.

In extreme towing conditions it is still recommended to turn off the O/D and tow in 3rd gear. This will keep the engine rpm higher to maximize coolant flow through the radiator and spinning the mechanical fan faster to increase the air flow across the radiator.

Radman · **Posted:** Tue May 17, 2011 4:34 pm

I thought turning off the OD only prevented the tranny from shifting into 5th gear. Can you actually keep it in 3rd? I could have sworn mine automatically shifts from 3rd to 4th no matter if OD on or off. Maybe it is the lock-up feature that has me confused and I am still trying to figure out how this slushbox works

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

With OD off the KJ CRD uses 3rd as the top gear. You are noticing the lock-up engaging most likely. 4th and 5th gears are reserved for 'Drive' only.

LibertyCRD · **Posted:** Tue May 17, 2011 5:04 pm

So with the OD button turned "on", the towing tune won't allow 5th gear unless you hit 70 MPH? So that tune would be for people who tow a lot of the time only then I take it. Even though the 4th to 5th ratio change isn't much on paper, the engine really is loud on the highway in 4th. That would get annoying FAST unless you were using it to tow all the time.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

If you have the "towing" tune and are not towing one can accelerate to 70 mph to get 5th gear and then slow back down to cruising speed. After 5th gear is engaged it will hold the gear down to 53mph. In this manner you can cruise in 5th or 4th depending on the current needs from the CRD. The "towing" tune just makes 4th gear more useable when it can actually be beneficial.

irollgen4s · **Posted:** Tue May 17, 2011 9:13 pm

I would be interested if you could make a tune that is sort of a more "highway" geared tune. I drive at mostly higher speed roads, and eventually im looking into getting your hot tune and TCM tune, but ideally i would need something that is at peak lowest RPM(for MPG) at about 65-70. At least thats where i'd like 5th to be. Kind of a trade off between completely town and completely highway.

Hope that makes sense :banghead:

dieseldoesit · **Posted:** Tue May 17, 2011 9:59 pm

irollgen4s wrote:

I would be interested if you could make a tune that is sort of a more "highway" geared tune. I drive at mostly higher speed roads, and eventually im looking into getting your hot tune and TCM tune, but ideally i would need something that is at peak lowest RPM(for MPG) at about 65-70. At least thats where i'd like 5th to be. Kind of a trade off between completely town and completely highway.

Hope that makes sense :banghead:

The only way to adjust rpm's for a given speed AND gear is to change your gearing in your axles or change your tire size.

The GDE trans tune for towing just restricts the 4-5 shift until 70 MPH, instead of the normal 55 MPH with their regular trans tune.

irollgen4s · **Posted:** Tue May 17, 2011 10:01 pm

from what i understood, their normal TCM(not towing) changes the shift points? I could be wrong though.

dieseldoesit · **Posted:** Tue May 17, 2011 10:05 pm

irollgen4s wrote:

from what i understood, their normal TCM(not towing) changes the shift points? I could be wrong though.

that is correct

BlackLibertyCRD · **Posted:** Tue May 17, 2011 10:06 pm

It would be OK for the towing tune if we can turn it off when not towing. Better yet have a switch to get economy tune when not towing. I would just like to have a switch to cancel 5th gear when towing. All other gears work normal. Is that possible?

dieseldoesit · **Posted:** Tue May 17, 2011 10:08 pm

BlackLibertyCRD wrote:

It would be OK for the towing tune if we can turn it off when not towing. Better yet have a switch to get economy tune when not towing. I would just like to have a switch to cancel 5th gear when towing. All other gears work normal. Is that possible?

I wish it was, but I think GDE has stated before that it isn't possible, or that you would need two TCM's. I am right there with you though, I would love to have that option.

mrb91 · **Joined:** Wed Mar 31, 2010 12:34 pm **Posts:** 23

I wonder if with the tuning of the trans if you could get the OD off button to work for both 4th and 5th gears. Since currently there is no way to have control of all five gears. I would love to see if you could program the OD off button to go from 5th to 4th with a single tap, then 4th to 3rd with a second tap say within ten seconds. Then after that time frame each time you tap the button it would up shift. Or better yet each time you hit the OD off button it would shift, say it would downshift if your throttle input is 30% or more and upshift if less then 30%.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Would be a great feature to have. Based on the current hardware it is not possible. A stand alone chip that intercepts the TCM signals to manipulate the gear demand and logic to control the OD button output would be necessary to create a dial-a-gear shift strategy. Or new TCM software from Chrysler, which would cost a small fortune and an act of God.

LibertyCRD · **Posted:** Wed May 18, 2011 2:11 pm

A simple 6-speed manual swap kit for U.S. CRDs would solve every one of these problems and you'd never even hear the phrase "TCM" mentioned on the forums anymore. In fact, this would be the cure for more than just TCM issues...the sluggish tranny early in the morning problem would be gone too.

irollgen4s · **Posted:** Wed May 18, 2011 10:21 pm

i WISH they offered a stick version in the US. Would be ten times more fun/easier

DOC4444 · **Posted:** Fri May 20, 2011 8:15 pm

I have a GDE TCM "Tow Tune" on the way.

DOC

GDE Trans Tune options

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