GDE transmision tune

cricket · **Posted:** Mon Jun 27, 2011 9:25 am

I have done the GDE eco tune. now i am considering doing the transmission tune. i would like to have input from owners that have done this. i have an 06 crd with the f37.
thank you, cricket.

papaindigo · **Posted:** Mon Jun 27, 2011 9:57 am

2005 with a TCM that had escaped the F-37. I've got about 3,000 miles on the regular TCM tune and a stock transmission/torque converter with no issues. Other than the final shift speed the tune is nothing like the pre-F-37 situation but I do like it. The shift into 3rd lockup at about 35 mph takes a bit of getting used to as it almost feels like the engine is lugging but it isn't.

No real towing experience with this tune yet but it should do fine with what little I do (2,000 lbs boat pkg but on flat terrain).

changingtime · **Posted:** Mon Jun 27, 2011 11:22 am

The GDE Trans Tune is awesome. I went back to the stock engine tune b/c of emissions (everyone thinks i'm crazy but I have to get testing done).

The trans tune drives very similiar to a performance vehicle...the rpms don't come crashing down when you let off the pedal.

I would highly recommend it...it may take you a week to get used to it...but it is awesome.

LibertyCRD · **Posted:** Mon Jun 27, 2011 12:29 pm

It does take a while to get used to it. for me, it made my tranny much more "clunky" and i lost that smoothness that the 545RFE is known for.. but the fuel economy gain was noticeable and so with it putting more $$ in my pocket it was hard to argue with.

dieseldoesit · **Posted:** Mon Jun 27, 2011 5:03 pm

LibertyCRD wrote:

It does take a while to get used to it. for me, it made my tranny much more "clunky" and i lost that smoothness that the 545RFE is known for.. but the fuel economy gain was noticeable and so with it putting more $$ in my pocket it was hard to argue with.

agreed completely. The clunkyness is much more noticable when doing a lot of city driving. Note that I have the stock ecu tune, no money for the ECO engine tune yet.

Liberty, do you have the stock engine tune as well?

I wonder if those that have clunkyness have the stock tune, and those that do not have an upgraded engine tune?

Any thoughts to this?

DOC4444 · **Posted:** Tue Jun 28, 2011 7:04 am

Only driven both GDE trans tunes with HOT ECU tune. I think there is confusion here. The only issue with " smoothness" has to do with driving much more under 1800 rpm. The engine vibrates a bit when applying power at low rpm. This does not occur with stock trans tune because as soon as you apply any power at low speed, the TC unlocks, the revs instantly go up and the motor is dramatically smoother above 1800 rpm. However, I consider the 3 MPG to be a good tradeoff. When towing a heavy trailer it has even more benefit.

Also, if funds are limited, I strongly suggest the ecu tune over the trans if you cannot afford both right away.

DOC

papaindigo · **Posted:** Tue Jun 28, 2011 9:15 am

X2. I'm happy with both but the biggest mpg bang for my buck at least was from the EcoTune. As to post TCM tune shifting; I don't really notice a significant difference in the shift. What I do notice is 1) I can "feel" the drive train more in 3rd at low RPM (35mph) which is clearly because of the new lockup but that quickly goes away as mph comes up. FYI this is really only noticable if I happen to hit that shift going uphill under relatively low acceleration - if I pushed the throttle a bit harder I'd blow right past the "non-issue" or to put it another way my driving habits make this more apparent than it otherwise might be; and 2) rpms don't drop abruptly when I take my foot off the throttle in 3rd gear but again that's because of the lockup. Neither of these are any surprise at all given the way GDE setup the TCM tune.

dieseldoesit · **Posted:** Tue Jun 28, 2011 10:10 am

DOC4444 wrote:

I think there is confusion here. The only issue with " smoothness" has to do with driving much more under 1800 rpm. The engine vibrates a bit when applying power at low rpm.

While I have felt the small increase in engine vibration at the lower rpms, that has not been part of the clunkyness that I have found with the tune. I did notice about a 3 MPG improvement though, and I am very happy with that.

DOC4444 wrote:

Also, if funds are limited, I strongly suggest the ecu tune over the trans if you cannot afford both right away.

live and learn I guess.

flman · **Posted:** Tue Jun 28, 2011 3:01 pm

Been happy with the TCM tune. Makes you feel like you have the drive line of a standard transmission = no wasted energy going to the slipping slush box. :google:

Joe Romas · **Posted:** Wed Jun 29, 2011 7:49 am

Have any of you done any type of a "Learning" procedure :BANANA:

Warp posted a driving procedure that forces your transmission controler to "adjust" to your particular transmission :wink:

Untill this is done your results may be less then desireable. Left on it's own it can take a long time for the TCM to fine tune settings by it's self but it will eventually :roll:

The time you say it takes you to "get used to it" maybe the TCM learning your transmission's parameters :JEEPIN:

dieseldoesit · **Posted:** Wed Jun 29, 2011 9:56 am

Is everyone doing the transmission learn procedure after they get the transmission tune?

I might give it a try this weekend and will let you know of the results.

vshockey10 · **Joined:** Tue Apr 19, 2011 9:28 am **Posts:** 59

anyone have the link to that procedure?

LibertyCRD · **Posted:** Thu Jun 30, 2011 9:29 am

I read the "transmission learn procedure" steps and it looked like a sick joke. No way I'm wasting that much time or fuel screwing around on the road like that to "teach" the TCM.

I put thousands of miles on my GDE TCM tune and it was clunky the entire time. Under heavy acceleration it was smooth. But when slowing from 60 to 0 at a traffic light it was clunky and abrupt. While driving through the city 25-45 MPH it was also clunky and you could feel the shifts jerk you around in the seat. From a comfort standpoint, it was not optimal at all... which is why it did not come from the factory that way.

The ONLY reason to run the TCM tune is because it was easily increasing my mileage 2 MPGs over stock. I could verify clearly that it was putting $$$ back in my pocket... so I lived with it. I suspect the trans. fluid was staying a little cooler too, though I can't confirm.

Yes, I had the GDE HOT tune the entire time.

vshockey10 · **Joined:** Tue Apr 19, 2011 9:28 am **Posts:** 59

LibertyCRD wrote:

I read the "transmission learn procedure" steps and it looked like a sick joke. No way I'm wasting that much time or fuel screwing around on the road like that to "teach" the TCM.

I put thousands of miles on my GDE TCM tune and it was clunky the entire time. Under heavy acceleration it was smooth. But when slowing from 60 to 0 at a traffic light it was clunky and abrupt. While driving through the city 25-45 MPH it was also clunky and you could feel the shifts jerk you around in the seat. From a comfort standpoint, it was not optimal at all... which is why it did not come from the factory that way.

The ONLY reason to run the TCM tune is because it was easily increasing my mileage 2 MPGs over stock. I could verify clearly that it was putting $$$ back in my pocket... so I lived with it. I suspect the trans. fluid was staying a little cooler too, though I can't confirm.

Yes, I had the GDE HOT tune the entire time.

So what mpg were you getting with the HOT tune, tcm economy tune, and the 255/70/16 tires?

I ask because this looks to be the direction that I am heading

LibertyCRD · **Posted:** Thu Jun 30, 2011 1:45 pm

vshockey10 wrote:

LibertyCRD wrote:

I read the "transmission learn procedure" steps and it looked like a sick joke. No way I'm wasting that much time or fuel screwing around on the road like that to "teach" the TCM.

I put thousands of miles on my GDE TCM tune and it was clunky the entire time. Under heavy acceleration it was smooth. But when slowing from 60 to 0 at a traffic light it was clunky and abrupt. While driving through the city 25-45 MPH it was also clunky and you could feel the shifts jerk you around in the seat. From a comfort standpoint, it was not optimal at all... which is why it did not come from the factory that way.

The ONLY reason to run the TCM tune is because it was easily increasing my mileage 2 MPGs over stock. I could verify clearly that it was putting $$$ back in my pocket... so I lived with it. I suspect the trans. fluid was staying a little cooler too, though I can't confirm.

Yes, I had the GDE HOT tune the entire time.

So what mpg were you getting with the HOT tune, tcm economy tune, and the 255/70/16 tires?

I ask because this looks to be the direction that I am heading

With this setup, 25 MPG in mixed 50/50 city/highway driving and 26-27 on the highway...in the Summer on good fuel when the weather is warm. 22ish in the Winter.

cricket · **Posted:** Thu Jun 30, 2011 7:57 pm

vshockey10 wrote:

anyone have the link to that procedure?

I have no link to to the learning procedure. what allison engineers have told me about their control module is, "don't try to push it. drive with your normal habit and let it learn on it's own. it takes time but it will adjust". i am assuming the jeep will do the same. does this help at all?

vshockey10 · **Joined:** Tue Apr 19, 2011 9:28 am **Posts:** 59

Yes it does thank you. I wish I would have read that initially. Because I just installed the GDE trans tune now and went for a spin pedal to the metal lol

But anyways GDE is a great company to deal wit, Keith your the man. Only thing I wish he did was a on the fly way to switch between the eco tune and HOT tune. I can't wait to see the mpg increase and continue modding my CRD.

DOC4444 · **Posted:** Fri Jul 08, 2011 5:48 am

Never any issues slowing from 60-0 like Liberty CRD. Always seemlessly smooth. Never felt the need to alter GDE trans tune characteristics with a learning procedure.
DOC

vshockey10 · **Joined:** Tue Apr 19, 2011 9:28 am **Posts:** 59

how do the rest of you guys like your GDE trans tune? I just put mine on and I'm not to sure if I like it. I am running a hot gde tune also. The acceleration was significantly increased with the HOT tune. Now I put the trans tune on and it seems like its a turd again. I will probably keep it if I do in fact get the claimed 8% mpg increase

DOC4444 · **Posted:** Sat Jul 09, 2011 7:22 pm

VS,

As soon as you touch the throttle at any speed, the stock TCM immediately unlocks the TC and depending on speed and how deep you get into it, may shift the trans down one or even two gears. This instant rise in revs and "slippage" of the TC gives you the feeling of "peppiness", but is very wasteful of the motor's energy. If you had a manual gearbox, this would be like always instantly downshifting when you just crack the throttle open a tiny bit, regardless of whether you require strong acceleration or not at that particular moment. Diesels are particularly rpm sensitive in terms of fuel consumption. You want to keep the revs as low as possible and use the diesel torque so you minimize fuel consumption.

The stock TCM does not allow you to do this. GDE's TCM does. When you apply moderate throttle with the GDE TCM, the TC remains locked and the trans does NOT downshift. This saves fuel. If you want max acceleration, the latest version of the GDE TCM requires that you apply more than 3/4 throttle to unlock the TC and trigger a downshift, or you can manually downshift, or if you are in 4rth or 5th gear, you can hit the "OD Off" button on the side of the shifter. It's all very easy if you think and act the way you would if you had a manual trans. The TCM has not affected your power output. If you floor it now, your Jeep will accelerate just as fast with the GDE TCM as it used to. It just gives you options you didn't have without it.

If you miss the "peppy" feeling, go back to the OEM TCM. The price will just be about 3 MPG.

(When I first installed the prototype GDE TCM, my wife told me it felt like her Jeep had a "restrictor plate".)

DOC

GDE transmision tune

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