GDE Trans Tune

Joe Romas · **Posted:** Sun Dec 26, 2010 8:32 pm

I saw a 2-3 mpg increase when I got a pre f37 tcm and most of my driving is short trip city driving :jester:

LibertyCRD · **Posted:** Mon Dec 27, 2010 2:10 pm

dthdcrd wrote:

I have the trans tune and the hot tune. I drive about 30k per year, combination of city and highway. I tow a 4k lb open car trailer at least once a month.

I really enjoy the jeep with these tunes. The trans tune is nice because you are in much more control. It is as close to a manual as you can get. In my experience you can apply much more throttle once it locks up in third than you can in 4th or 5th before it unlocks. A really good example of this is let the trans shift from 1st to 2nd to 3rd at about 2200 RPM once it locks up in 3rd apply 3/4 or slightly more throttle. This is right in the sweet spot of torque and the jeep will come alive and motor up to sixty before you know it. As you understand how it behaves you can play with the throttle and how to drive the jeep to best suit your needs/style.

One dislike I have,which only happens while towing. I have a number of mild hills leaving my neighborhood with a 35-40MPH speed limit. When I hit the incline of the hill I am just approaching 30 to 35 MPH, the torque converter locks up an no matter how much throttle I apply the jeeps falls on its face. I have to either hold the throttle down far enough to prevent it from locking until I reach the top of the hill (which I am usually speeing by then) or let it lock up and drop speed, then apply enough throttle to unlock and gain to much speed, relase a little throttle and it locks again loosing speed... You get the idea. In short it is difficult (while towing and up hill only) to hold a steady 35-40 MPH.

Other than that one scenario all is good and a blast to drive.

Good feedback guys... keep it coming.

LibertyCRD · **Posted:** Wed Dec 29, 2010 5:53 pm

Well I just installed my GDE TCM. Took about 15 mins. Was very simple to do. In the process of updating my HOT tune now.. Can't wait to try it out! :BANANA:

I'll post impressions later...

Update:

I took the Jeep for a spin to see how this thing drives now with the new TCM program.

Pros:
-Much faster from 0-60. This thing flies now. Wow.
-Stays locked up a LOT more on the 55 MPH highways as well as in town.
-Causes the Jeep to run a lot quieter, especially in town. I can really hear the tires sing now. Might have to fix that next. :shock:

Cons:
-The 1-2 shift is funky. Jeep falls on it's face then picks back up again.
-Under heavy throttle from a stop, it shifts too early for my taste. I'd like to see a little bit more RPM before shifts.
-Between 55 and 75 if you are under heavy throttle (to make a pass for instance) the tranny acts a little funky and you can feel the clunkiness.

Overall, I think I'm going to like it when I get used to it. It certainly is more driveable for daily use and should help MPGs slightly. Going to put some mileage on it and report back later.

LibertyCRD · **Posted:** Wed Feb 02, 2011 1:36 pm

Just an update..

I'm still really enjoying the TCM tune. It's getting to the point now where I can't imagine going back to the stock tune. It does make the shifts more "clunky" and the tranny isn't smooth as butter anymore but the MPG tradeoff is worth it.

I'm still consistently seeing 8% better MPGs with the tune than what I was getting before. That's awesome because this tune is definitely going to pay for itself!

dieseldoesit · **Posted:** Wed Feb 02, 2011 7:19 pm

LibertyCRD wrote:

Just an update..

I'm still really enjoying the TCM tune. It's getting to the point now where I can't imagine going back to the stock tune. It does make the shifts more "clunky" and the tranny isn't smooth as butter anymore but the MPG tradeoff is worth it.

I'm still consistently seeing 8% better MPGs with the tune than what I was getting before. That's awesome because this tune is definitely going to pay for itself!

You still at 22.4 MPG? According to your fuelly?

LibertyCRD · **Posted:** Wed Feb 02, 2011 8:44 pm

dieseldoesit wrote:

LibertyCRD wrote:

Just an update..

I'm still really enjoying the TCM tune. It's getting to the point now where I can't imagine going back to the stock tune. It does make the shifts more "clunky" and the tranny isn't smooth as butter anymore but the MPG tradeoff is worth it.

I'm still consistently seeing 8% better MPGs with the tune than what I was getting before. That's awesome because this tune is definitely going to pay for itself!

You still at 22.4 MPG? According to your fuelly?

Yeah that's my annual average.

In Winter weather like this, I was consistently seeing 20.0 MPG. Now with the GDE TCM tune, I'm consistently pulling 21.5 MPG and this tank I'm on right now is going to end up even better. It's the only mod I've ever done to a CRD that CLEARLY made an improvement. The increase from the ECU tune and the intake/exhaust mods have been questionable, but the TCM tune is the real deal.

Joe Romas · **Posted:** Fri Feb 04, 2011 7:32 pm

I have the "original stock" (pre f37) tcm ALL our CRD's came with. It has no down side and when needed it downshifts without giving it 3/4 throttle. Chrysler had it right the first time :goink:

I have the GDE "Full torque" tune and Euro TC and front pump. The shifts are hardly noticable and occure at the right time for me. Not like the f37 that always seemed to be shifting at the wrong time. The TCM did need to relearn and using Warp's procedure it was a snap :SOMBRERO:

I'm getting 2 or more depending on conditions, miles per gallons and for me that's closer to 10% :-)r

I liked it form the very start and 4 months later still liking it :jester:

I now have the Jeep I paid for :JEEPIN:

LibertyCRD · **Posted:** Fri Feb 04, 2011 8:41 pm

I also had a non-F37 TCM before the GDE TCM. And the non-F37 TCM was total garbage. It wasted so much torque and fuel that it was ridiculous. With GDE, I now have it the way Jeep should have sold

dieseldoesit · **Posted:** Fri Feb 04, 2011 8:56 pm

LibertyCRD wrote:

I also had a non-F37 TCM before the GDE TCM. And the non-F37 TCM was total garbage. It wasted so much torque and fuel that it was ridiculous. With GDE, I now have it the way Jeep should have sold

care to explain?

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

The pre-F37 trans tune has the following characteristics:
no 3rd gear lock-up when in drive, if the o/d is off the top gear is 3rd and it will go into lock-up around 40mph
4th gear lock-up occurs around 50-52mph
5th gear lock-up occurs at 58 mph
no lock to lock shifting
will unlock when pulling a trailer in drive with torque demand above 230 ft*lb in lower engine rpm situations

GDE trans tune
3rd gear lock-up at 35mph, if the o/d is off the top gear is 3rd and it will go into lock-up at 35mph
4th gear lock-up occurs at 46mph
5th gear lock-up occurs at 58mph
lock to lock shifting enabled, this makes the shifts much quicker and alleviates the need for a shift kit
will unlock when pulling a trailer in drive with torque demand above 270 ft*lb in lower engine rpm situations, this will vary based on the engine tune the CRD is using

The GDE trans tune is more fuel efficient than stock in city driving conditions since the vehicle will be running in lock-up most of the time (after warm-up period when trans remains unlocked until tranny fluid is warm). Increasing the % of lock-up helps to reduce transmission fluid temps due to no heat generated from a slipping torque converter. This also equates to less fuel usage.

OldSkull · **Posted:** Sat Feb 05, 2011 10:12 am

LibertyCRD wrote:

Cons:
-The 1-2 shift is funky. Jeep falls on it's face then picks back up again.
-Under heavy throttle from a stop, it shifts too early for my taste. I'd like to see a little bit more RPM before shifts.
-Between 55 and 75 if you are under heavy throttle (to make a pass for instance) the tranny acts a little funky and you can feel the clunkiness.

Did you follow the drive Learn procedures for the TCM after the installation?

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=98&t=49854

Joe Romas · **Posted:** Sat Feb 05, 2011 11:40 am

GDE

Can you post the F37 shift points too :?:

Thanks
Joe

LibertyCRD · **Posted:** Sat Feb 05, 2011 5:12 pm

My FAVORITE thing of all is that I can take my foot off the pedal completely (cars slowing in front of me) and the TC will stay locked up. No roaring RPMs as soon as I feather back into the pedal. That alone makes the GDE tune worth it.

The 8% better economy, cooler tranny, faster acceleration, quieter operation in town, etc. etc. is just a bunch of bonus goodness.

ihavelotsoftoys · **Posted:** Thu Feb 10, 2011 7:47 pm

Anyone who owns a CRD should get the trans tune. I got the Full torque ECO tune with the trans tune. I also put in a suncoast last summer.
This is the way a diesel should run. Love the quick upshifting and lack of downshifting when I push down with the right foot!
Normal driving with light foot and the engine never goes over 2000RPM.
Getting at least 10% bump in MPG. Was always 20, now 23+ but still to early to tell. I'll report back in a few months.
If your are considering having GDE tune your trans and engine, DO IT!!!
I had the other brand in it was no good, smoked like hell. It was a lot of fun, but this is nice!!

GDE Trans Tune

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