GDE TCM Tune, a review.

CRDMiller · **Posted:** Thu Jun 03, 2010 2:19 am

So, i received my GDE tcm tune today, it's nice.

I have the in motion stage II tune and also i have the afaik the factory TC. This Tc shuddered when it was stock, and obviously more so with the imII, i usualy drive around it.

I have 32 inch diameter tires, so the situation is somewhat a worse case scenario.

My initial, one day, 50 mile impressions;

That said i absolutely love the tune thus far, the around town tc lockup and locked shifting is simply great. There is a little bit if NVH increase especially around 35-40 where to tip in and out on the throttle as the tc locks and unlocks. Under normal driving conditions i experience no shudder whatsoever other than the romp on it at 35 approx 1400 rpm third locked, between 50% to 60% throttle (>60% unlocks and seemingly >70% grabs second locked?) (sure is fun and sound great, to boot).

Basically any time i go over 20 psi of boost and >50% throttle while locked under 1800 rpm witch again is not normal driving for me.

It is also verry difficult to stay at 35 mph however i will learn, it accelerates effortlessly up to about 40 with verry little throttle input, were talking 5-8%

I would REALLY like to see gde take it further and at least change the programming of the overdrive button. I want it to drop ONE gear down and lock when od is off, because i cant get it to go into "fourth" (really fifth) aka 0.75:1 to save my life. (at road speeds) Shifting into "2" should imho, drop two gears and lock, (if possible) shifting into "one" should grab the third gear down, and again, lock, if possable (perhaps the "one" programming is not really necessary? maby make "one" = 2nd Prime 1.50:1 no matter what) I would REALLY like to be able to lock into 0.75:1 while towing. I used ot be able to do this by NOT accelerating to 66 mph, where my f37/f23 configuration would shift into final od aka 0.67:1 this would allow me to have approximately 2k rpm at 65 mph instead of 1705 rpm at 65 at my choice.

Who uses second anyway? if you want od off stock functionality, shift to second. cant loose?

Perhaps i would not care if i had a euro tc? When suncoast make a nice tc with upgrades springs, we'll find out.

Anyway i look forward to seeing what gde does with this tune in the future, because as far as i am concerned, it needs to deal with the 0.75:1 issue.

LibertyCRD · **Posted:** Thu Jun 03, 2010 9:04 am

In my opinion, having two OD gears was the dumbest thing Chrysler ever did. They should have used ONE overdrive, and the other 4 gears for performance/acceleration/town driving to improve economy and driveability. The ratios are stupid on this trans. Otherwise, it's great.

Please continue to post your thoughts on the tune as you drive it more.

Joe Romas · **Posted:** Thu Jun 03, 2010 3:13 pm

LibertyCRD wrote:

In my opinion, having two OD gears was the dumbest thing Chrysler ever did. They should have used ONE overdrive, and the other 4 gears for performance/acceleration/town driving to improve economy and driveability. The ratios are stupid on this trans. Otherwise, it's great..

I personally think the ratios are very good just the TCM is not taking advantage of them :lol:

In my case towing a trailer I sure would like to be able to actually use 4th gear going up grades :SOMBRERO:

As soon as you hit a grade it drops from fifth gear to third :banghead:

That's the dumb part and thats the F37 TCM programming :JEEPIN:

Diesel engines don't have the rpm flexability of a gasoline engine and you need a wide range of gears.

If you want more preformance and acceleration you chose the wrong vehicle :seuss:

LibertyCRD · **Posted:** Thu Jun 03, 2010 6:14 pm

Joe Romas wrote:

LibertyCRD wrote:

In my opinion, having two OD gears was the dumbest thing Chrysler ever did. They should have used ONE overdrive, and the other 4 gears for performance/acceleration/town driving to improve economy and driveability. The ratios are stupid on this trans. Otherwise, it's great..

I personally think the ratios are very good just the TCM is not taking advantage of them :lol:

In my case towing a trailer I sure would like to be able to actually use 4th gear going up grades :SOMBRERO:

As soon as you hit a grade it drops from fifth gear to third :banghead:

That's the dumb part and thats the F37 TCM programming :JEEPIN:

Diesel engines don't have the rpm flexability of a gasoline engine and you need a wide range of gears.

If you want more preformance and acceleration you chose the wrong vehicle :seuss:

I disagree. Performance and acceleration is KEY when towing and working, which is specifically what a diesel SUV is for. If Chrysler had taken advantage of the extra gear and spread the ratios properly (like the other 5 and 6 speeds on the market) they could have made towing, fuel economy, acceleration, and every thing else much more desirable on this vehicle. The 545RFE is an excellent trans...especially compared to every other Chrysler trans. in existence. ALL of the complaints, though, that I've ever seen about it relate to the pathetic gear ratios.

JL Rockies · **Posted:** Thu Jun 03, 2010 7:32 pm

I just bought the CRD because it's gangster off road.

DOC4444 · **Posted:** Thu Jun 03, 2010 9:31 pm

CRD Miller,

You should not be experiencing ANY unlocking of the TC above 35 MPH UNLESS normal operating temp has not yet been reached or you are applying more than 3/4 throttle. Not having a truly adequate TC should not affect this other than the clutches may slip and shudder when the TC is TRYING to lock. The GDE TCM does not know what TC you have installed and will continue to instruct the TC to remain locked as soon as 35+ MPH is reached and continue as long as above 35 MPH is maintained.

Given the huge number of posts prior to release, I am really surprised that there has been relatively so little buzz on this site now that the GDE TCM tune is actually available and priced at only $200, at the moment.

It far exceeds almost everyone's hopes and expectations.

DOC

LibertyCRD · **Posted:** Thu Jun 03, 2010 10:28 pm

JL Rockies wrote:

I just bought the CRD because it's gangster off road.

You're a pimp man. I love you. In a brother kind of way. :jester:

kapalczynski · **Posted:** Thu Jun 03, 2010 11:55 pm

Hows your economy with this tune? City & hwy (like 47mph hwy...lol) before and after tune gains.

- Mark

CRDMiller · **Posted:** Fri Jun 04, 2010 1:54 am

At 35-40 mph, for me, at least, when i let off the throttle completely, it does indeed unlock, when i reapply throttle, it again locks. This happens for me because at 1-2% throttle at 35 mph, it accelerates. I have difficulty maintaining 35 mph speeds. this is probably because of the in motion tune. I put another 80 miles on it today driving around, and i really like it.

As far as the price, i'm positive i paid 300 dollars, i had assumed that was after the 100 dollar sale. No biggie.

For the economy gains around town, i can not really weigh in, i think it surely must lead to some gains, especially in the 35 mph zones and also 45's, however I've been playing with it a lot and not trying to get mpg, that said i don't think it's possible for it to not have improved mpg as the tc is locked, that's instant mpg.

This is especially useful to me as i have a nice 8 mile urban commute before i hit the freeway that i need to be on, to get to work.

Also merging onto a freeway, is effortless, yes it always was, but now it's more so. I do not rev all day at 2500 rpm until i hit 55 like with f37.

Really i can honestly say that if you are even considering this tune, get it. EXCEPT if you like the idea of towing at 65 mph anywhere near 1900-2200 rpm.

emp1134 · **Posted:** Fri Jun 04, 2010 3:22 am

DOC4444 wrote:

CRD Miller.....
Given the huge number of posts prior to release, I am really surprised that there has been relatively so little buzz on this site now that the GDE TCM tune is actually available and priced at only $200, at the moment.
DOC

How do you get it for $200?

Joe Romas · **Posted:** Fri Jun 04, 2010 6:52 am

CRDMiller wrote:

EXCEPT if you like the idea of towing at 65 mph anywhere near 1900-2200 rpm.

Can you elaborate on this a little :jester:

Joe

DOC4444 · **Posted:** Fri Jun 04, 2010 9:08 am

It is not working properly if the TC is unlocking when you let off UNLESS your speed drops below 35MPH (then it is normal). Contact Keith at GDE if this is the case.

Regarding MPG, we have seen a consistent 3 MPG increase with the GDE TCM when NOT towing at under 55 MPH speeds. Highway mileage is only improved when towing because it avoids unnecessary downshifts on slight upgrades that never occur when not towing.

Price: GDE site says: "Our spring sale is now on! All tunes are marked down $100." (That's $200 by my math for the TCM.)

DOC

dieseldoesit · **Posted:** Fri Jun 04, 2010 10:37 am

DOC4444 wrote:

Price: GDE site says: "Our spring sale is now on! All tunes are marked down $100." (That's $200 by my math for the TCM.)

DOC

The prices currently reflect the 100 markdown (300 price, assumed 400 before mark down), hence the ECO tune is 450 (originally 550).

I agree on a more usable 4th. It is lame when towing that sometimes 5th is too much gear, but when it drops down into 3rd, it is too little. A real 4th would be good to have and to be used around the 65mph range.

kapalczynski · **Posted:** Fri Jun 04, 2010 1:44 pm

Not sure if it is possible, but it would be nice to make a "hold" button to keep it in the gear you have it (some built in safeties like shifting at redline or down shifting at too low RPMS would make sense with a Hold button). That way you could press hold, keep it in 4th and go up and down the rpms and stay in your gear. A auto stick or paddle shifters would be nice while I'm dreaming.

I know the Chevrolet Aveo has a hold button to keep it in a gear due to it being sooo underpowered. I drove one once...lol The jeep TCM may not even have the necessary inputs/outputs for something like this though.

CRDMiller · **Posted:** Fri Jun 04, 2010 2:15 pm

I set out to make a video to demonstrate the "unlocking" at tip out.

In doing so, i realized that, the tc was in fact, not unlocking. DOC4444 is correct. I'd like to apologizes to doc and gde.

At exactly 35 mph indicated, it locks into third at 1400 rpm. What i though was the tc unlocking (under closer examination it is not) was in fact what appears to be drive line slop, that I consider to be normal. While driving it was hard to tell, but upon watching the video, it is obvious.

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

Just to clarify, all the engine tunes are marked down $100 and the purchase price already reflects this. The trans tune is a new service and no markdown on the price point, it is $300.

The gear spacing on the 45RFE trans is less than ideal for 4th gear. The 3rd gear ratio is 1, the 4th gear ratio is 0.75 and the 5th gear ratio is 0.67. Ideally 4th gear would have a ratio of 0.84 as this would provide an even split between 3rd and 5th.

If a customer wants more 4th gear, it would require pushing the 5th gear out to about 65-70mph. However, this will hold true for all driving conditions, even when not pulling a trailer. Consequently, the fuel economy might not be as good due to running with higher engine revs. With a trailer, more 4th gear would allow for less trans unlocking while traversing hills and reduce the overall gear hunting.

grywlfbg · **Posted:** Sat Jun 05, 2010 1:00 am

dieseldoesit wrote:

I agree on a more usable 4th. It is lame when towing that sometimes 5th is too much gear, but when it drops down into 3rd, it is too little. A real 4th would be good to have and to be used around the 65mph range.

I thought that turning the OD off causes it to lock up in 4th?

If I start to climb a hill when towing and do nothing it will downshift on its own and revs will REALLY climb and it won't lock up. I assume it's in 3rd at this point. The reason I say that is because if I anticipate the hill and hit the OD off button the revs will be lower for the same speed and it will lock up - I assume this is in 4th gear.

All that to say my towing technique os to leave it in OD until my speed drops to 55 mph (I tow at 65 mph) and then I hit the OD switch. I then stay at 55 mph until I crest the hill and switch the OD back on and hit resume on the cruise for 65 mph.

Joe Romas · **Posted:** Sat Jun 05, 2010 6:29 am

grywlfbg wrote:

I thought that turning the OD off causes it to lock up in 4th?

Both 4th and 5th are overdrives :jester:

So OD OFF is THIRD :BANANA:

warp2diesel · **Posted:** Sun Jun 06, 2010 9:30 pm

GreenDieselEngineering wrote:

The gear spacing on the 45RFE trans is less than ideal for 4th gear. The 3rd gear ratio is 1, the 4th gear ratio is 0.75 and the 5th gear ratio is 0.67. Ideally 4th gear would have a ratio of 0.84 as this would provide an even split between 3rd and 5th.

Don't all the US/Canada CRDs have the 545RFE?

I know mine does.

Typo?

RTStabler51 · **Posted:** Mon Jun 07, 2010 8:43 am

grywlfbg wrote:

dieseldoesit wrote:

All that to say my towing technique os to leave it in OD until my speed drops to 55 mph (I tow at 65 mph) and then I hit the OD switch. I then stay at 55 mph until I crest the hill and switch the OD back on and hit resume on the cruise for 65 mph.

That's what I do.

GDE TCM Tune, a review.

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