GDE Trans Tune

Ripster · **Posted:** Fri Jun 25, 2010 4:05 pm

This past weekend I drove down to Wixom Mi and Keith came out and updated my ecotune and did the
tranny tune. Very nice for the type of driving I do. Before last shift was 62, on mine it now shifts for the
last time at 56 mph. About 35 and 45 for the 3rd and 4th gears. Very smooth and I have gone as low as
50 and stayed locked up with light throttle. The evic showed 40.2 before the ecotune up with hand calculator at 31mpg. So a bit of range. On the way home, the Evic showed 34 and hand calculated was 30-31 so a bit closer.
I took a picture of the 40.2 probably will not see that again.

My transmission has always been very smooth and when accelerating moderately or causually as is generally
the case the shifts are quick and smooth. You will feel the shift from 4th to 3rd when coasting down around
the 35 mph area, but only slightly--no more than usual with this vehicle. Overall very pleased, I can now drive
55 and up without always shifting, which is a pleasure where I live, and it still cruises on the freeway like it always
did. Highly recommend the tune, locking up instead of running up a high rpm allows it to pull sooner and get out
of the way.

jeepdan · **Posted:** Fri Jun 25, 2010 6:32 pm

Sound good.

Metal Man · **Posted:** Tue Oct 05, 2010 10:47 pm

Does anybody have any more feedback on the trans tune?

DOC4444 · **Posted:** Wed Oct 06, 2010 10:24 pm

Metal,

Check my posts regarding the GDE TCM tune when it was first released. We have 15K on it now, lots of heavy towing (GDE HOT, Euro TC). We get 32-33 MPG in mixed local/highway driving (non-towing). (2-3 MPG of this is due to the TCM tune.)

DOC

CATCRD · **Posted:** Wed Oct 06, 2010 10:30 pm

I can post my experience with the new shift points.

1-2 @ 10mph
2-3 @ 18mph
3rd locks the TC at 33mph
3-4 @ 46mph without unlocking the TC
4-5 @ 56mph without unlocking the TC

It will stay locked and in 5th all the way down to 48mph with light throttle. Really good fuel mileage there.
Below that it will drop to 4th. Slow down below 43 and it will drop to 3rd and so on.

The biggest difference to me is that you are never in 4th gear with the torque converter unlocked. In stock form that is the case from 34mph to 50mph if you don't press O/D off.

LibertyCRD · **Posted:** Thu Oct 07, 2010 12:27 pm

See, that's my biggest gripe with the stock TCM is that if I've got light throttle applied and I'm cruising up a hill... and my speed is slowing down... once it hits 50 MPH the converter unlocks and you can see the tach. take off to the moon and it's just very annoying because you can feel that the engine still has plenty of power there.. but the tranny just won't hold it.

So the GDE tune will let the converter STAY locked from 5 to 4 to 3 as the Jeep slows down? Then if you gently press the pedal, it'll go 3 to 4 to 5 and stay locked the whole time?

What about WOT? Will it unlock and let the engine take off as normal under that condition?

All the reviews I've seen so far are pretty vague about how the tranny actually works with the tune in daily driving.

DOC4444 · **Posted:** Thu Oct 07, 2010 8:20 pm

Liberty,

Check my posts when the GDE TCM tune was in development.

To summarize, the TC locks @ 35 MPH and STAYS locked unless speed drops below about 32-33 OR if you apply about 3/4 throttle, unloaded. If you are towing 3000+ lbs as we frequently do (HOT tune), it can occur at less throttle because the system is sensing that engine is just being "lugged" too much.

If there is a downside, it is that you experience more vibration through the body on local/city roads because of spending a lot of time @ 1500-1800 RPM. However, that's where most of the fuel savings are, so it's your choice.

DOC

LibertyCRD · **Posted:** Sat Dec 25, 2010 10:31 pm

OK... all you guys that have the GDE TCM tune... post up your current thoughts. Still like it? Anything you don't like?

striperman36 · **Posted:** Sun Dec 26, 2010 12:09 am

DOC4444 wrote:

Metal,

Check my posts regarding the GDE TCM tune when it was first released. We have 15K on it now, lots of heavy towing (GDE HOT, Euro TC). We get 32-33 MPG in mixed local/highway driving (non-towing). (2-3 MPG of this is due to the TCM tune.)

DOC

That's still amazing, you must drive slower than me. If I keep it at 2K I'm gomna get killed,

I also seem to lower mileage cruisin locally, when I am just pushin 1500-1800 and coasting

DOC4444 · **Posted:** Sun Dec 26, 2010 12:32 am

Striperman,

There are a number of things that collectively yield these results. I offered to discuss them with you in detail and potentially demonstrate since you are so close by, but you never followed-up.

DOC

graum · **Posted:** Sun Dec 26, 2010 9:47 am

Just installed the tuned TCM on 12/23.

I've got a hill on my return home that always resulted in 2200-2300 rpm at 35-40 mph (too many curves to go faster). On my test drive after the install I saw about 1800 rpm for the same speed up the hill. I'm smiling.

graum
06 limited. ECO tune. and now TCM tune.

DOC4444 · **Posted:** Sun Dec 26, 2010 11:39 am

Graum,

That sounds like a moderate hill. If you are towing a heavy trailer or the grade increases significantly so that additional power is needed to maintain speed, at some point the TC will unlock and revs will go to what you used to see (2300, or higher).

My only concern is applying more than moderate torque under 2000 rpm when heavily laden and/or pulling a heavy trailer. We don't have any experience on this side of the pond with "lugging" these VMM motors. If we could get some experience from owners in the UK, Europe, Australia, etc., that would be helpful. (They can do it with their manual trasmissions. We couldn't here until the advent of the GDE trans tune.)

To be on the safe side, though, I just don't. I either use the gear selector, "lock" button or just go to full power (foot) to get the revs up to keep it from pulling really hard under 2000 rpm. BTW, the vibration increases significantly so you can literally feel it straining.

Who knows, maybe these things are so robust that they can put out full power (even enhanced by GDE/IM, etc) and torque all day long, everyday, at 1600 rpm, but I don't think its a good idea to push it that far.

Perhaps Keith may weigh in on this topic, but I think he is buried in other projects and may not be keeping as close an eye here as he used to.

DOC

LibertyCRD · **Posted:** Sun Dec 26, 2010 11:55 am

Well, I'd certainly like some opinions, because I'm considering dropping the hammer on the TCM tune....BUT, it is $300 and that's a lot of cash. So if it could cause issues down the road I'd like to know about it now.

DynoPax · **Posted:** Sun Dec 26, 2010 12:33 pm

I've had the GDE TCM tune since early October and really appreciate the lower RPM when cruising along... My only two concerns are when climbing a steep hill or overtaking without mashing the pedal (lack of HP in lower RPM). You either need WOT or unlock the transmission. Mind you, I do have the Hot tune as well but still feel the engine to be slightly underpowered in certain situations. I'm beginning to suspect issues either with the fuel/injection system or maybe a sludged up engine (running almost a full year with bad thermostat). I will try Auto-RX in oil and Seafoam in tank to find out if any improvement can be obtained... Apart from these annoyances, I must say the tunes have greatly improved the driving abilities, it's night & day when compared to the stock versions... Hope this helps!

flman · **Posted:** Sun Dec 26, 2010 1:08 pm

Metal Man wrote:

Does anybody have any more feedback on the trans tune?

I had it done 4 or 5 months ago, but I was not happy at first, I was almost going t send it back. Turns out I had a bad engine mount and the low RPMs made my vehicle feel and sound like something was wrong in the drive train. Now with 2 new engine mounts the tune is perfect, it lets you use that low end torque in the engine like you can with a standard transmission, you will not get this with any other TCM tune I know of, and you other choice are F37 and Non F37. It has increased my fuel mileage just the same. Keith did a good job here, and it is a worthy upgrade to your CRD.

flman · **Posted:** Sun Dec 26, 2010 1:09 pm

LibertyCRD wrote:

Well, I'd certainly like some opinions, because I'm considering dropping the hammer on the TCM tune....BUT, it is $300 and that's a lot of cash. So if it could cause issues down the road I'd like to know about it now.

With the hot tune and Euro TC, you will love it.

dthdcrd · **Posted:** Sun Dec 26, 2010 1:35 pm

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.

dthdcrd · **Posted:** Sun Dec 26, 2010 1:37 pm

I forgot. I have the euro TC as well. I am the third owner, went to the dealership complaining of the shutter.. They replaced it for free no questions asked. Lucked out on that one.

stoutdog · **Posted:** Sun Dec 26, 2010 2:26 pm

DOC4444 wrote:

Striperman,

There are a number of things that collectively yield these results. I offered to discuss them with you in detail and potentially demonstrate since you are so close by, but you never followed-up.

DOC

DOC, that's pretty impressive mileage. What are some of those "other things"?

I'm still figuring out how to drive on the TCM tune. Most of my driving is 60+mph so I don't really get the chance to play in the 35-50mph range.

striperman36 · **Posted:** Sun Dec 26, 2010 4:08 pm

DOC4444 wrote:

Striperman,

There are a number of things that collectively yield these results. I offered to discuss them with you in detail and potentially demonstrate since you are so close by, but you never followed-up.

DOC

Workin nights in a classified facility turns a brain to chopped liver. Still would like to know, as would others. that's a 50 pct increase in mpg, most people on fuelly are around 23.

GDE Trans Tune

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