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  Topic Review (Newest First)
01-13-2021 06:45 AM
[email protected] Thanks for the reply.. I'm definitely going to get more into the tuning adjustments and maybe even consider a different pcm. I have every trans mod imaginable in my 545rfe. Everything is heavy duty from the pump or drum assembly to the clutches. The valve body plate alone was 550.00 and the latest mod is the tuneless tuner. This is the 7th rebuild/ install of my trans by a good shop that I have been driving nuts! We didn't know what we were getting into! My 05 was a 5.7 and had around 200k miles on it and my fav vehicle. I bought a superchips tuner and flashed the 93 octane tune and that's all it took to wake it up and leave me wanting more. I bought a wrecked 06 charger cop car just for its 5.7, pulled the motor stroked it to a 6.4 394 cu in. good moderate cam and some head work with long tube headers put it in my jeep and tuned it with a diablosport tuner and was super happy with it and drove it for about 2 years (daily driver to work) without any work to the transmission which operated perfectly and had over 210k on it at the time. I figured it was time for a trans rebuild and went to a great shop and the initial cost was 5800.00 for a beefed up 545 guaranteed to handle 700 hp which is wasn't pushing and everything was perfect with the original pcm. Then the problems started. I had to try a 6.1. I bought a 6.1 based 426 stoker from Inertia motorsport and 3400 convertor and put it my Jeep and fried the clutches in my super beefed up 545 the 1st day. Lucky for me I had a warranty which they've honored 6 times now. I had to put another 1500.00 or so into even more trans parts for them to try to figure out why their bullet proof trans wasn't holding up and after trail and error and me researching every spare moment.. it was the pcm the entire time with not enough line pressure. figured out that 07 and newer can communicate with my tuner so I changed the pcm but am still working out the bugs. Everything is perfect except the service electric brakes and traction control display in the cluster. Performance wise everthing is very good except at WOT it doesn't engage smoothly. Sorry this ended up being a book.
01-12-2021 12:14 PM
90grandoneer Sounds like you're having way too much fun. Welcome to the forum. With your setup, I am not sure what differences there are (if any) between the 05 and 06 Jeep 5.7 PCM/TCM vs. any differences between the 05 Grand Cherokee and the 07 Commander PCM/TCM. When I did mine, I stuck with the same model.....06 Overland vs. 08 Limited, equipped pretty much the same. I did have lots of codes initially, but most dealt with mismatches between the two and had no effect on the operation of the vehicle and transmission.....everything worked as it should. I finally go rid of them though. The correct shift pattern also shows up on my cluster, just as it should. The only code that, at first, concerned me a little was, P2704, "Inadequate Clutch Element Volume 4C Clutch Circuit." Even with this code, everything worked fine and I've just recently found that there is probably really no problem at all. If I turn the 6 speed switch off with the HPT and go back to the stock 5 speed shift schedule, this code goes away. With the 6 speed shift schedule, it immediately comes back on the first time it is driven. I may just go back to the 5 speed schedule, as the main thing I was after when doing this mod. was to gain access to 2 prime when I wanted, which I couldn't do at all (except on kickdown) before. At least now I can manually up shift and 2 Prime is in that shift pattern.

Have you done any other mods. to the transmission?
01-12-2021 10:31 AM
[email protected] Hello all. I'm new to this forum and need to read through a lot more topics but started with this one. I have an 05 limited with a 07 commander pcm. I had to do this for trans/ tc control through HP due to burning up transmissions (low line pressure / etc) I almost have all of the bugs worked out but need any help possible. After I had the vin/ mileage flashed and tune my issues are the service electric brakes stays in my info display and I cant get the traction control light to go off. I have 3 different clusters Ive tried. My original 05 cluster wont show all 6 gears and it's weird when I have to downshift twice for it to show 5th. the 06and 07 clusters read the shift indicator perfectly but both say check gauges and for whatever reason won't display the coolant temp, just stays on the left and doesn't move. Performance wise bugs are in the kickdown and tc lockup. I'm sure I'll be asking many questions. Thanks in advance! My setup is a 05 grand cherokee limited with a 6.1 based 426 running a 3400 stall.
07-16-2020 06:27 PM
90grandoneer A little update on this "experiment" Today the wife and I took a 170 mile round trip up into the mountains (2500-6400 ft. elevation) and I am now on my 3rd rendition of up/down shift schedules, pressures and torque management settings, and I think I have it almost perfect, especially when driving in the mountains. About 20 miles of the run today was very winding and up hill with a lot of 15-30 mph curves. For this, it ran a lot in 2P (now 3rd) and 3rd (now 4th) and, surprising enough, I was amazed at how much MDS time I was getting going up hill in the lower gears. Overall, the 08 PCM allows for even more MDS "On" time than I used to get with the stock PCM, which was way more than stock. I also love that the MDS activation/deactivation is much smoother than it was with the stock PCM. Fuel economy for this trip, figured with a calculator, and with almost all winding (to some extent) mountain driving, was 20.79 mpg (170.5 GPS miles and 8.2 gallons) which is almost what I used to normally get on the highway with the stock PCM....21-23 mpg.

I am still fighting with the Diagnostic Code issues, but I am almost positive that most of them are related to the coincidental ignition switch beginning to fail. I took everything off the key so there was no additional weight of any kind on it, and I think that may have helped a little. I put the scanner on it as soon as we got home and, for once, there were no PCM codes, just the sometimes recurring lost communication codes. My, "Service 4WD Soon" message also went away. Below are most the codes I've been getting, most of them only one time. There are a few that do keep returning, but they are all stored codes and don't seem to affect the operation of any of the systems they're tied to. I am hoping a new ignition switch will fix most, if not all of them. Here's the codes I've gotten over about the past couple weeks.
The following were caused by me and scared the crap out of me. This is another story though.

The shift schedule first attempt was pretty good, but the shifts were so hard, they would rattle your teeth. I also had the up and down shifts too close together and a very slight touch on the throttle would force a downshift. I like it this way to some extent but this was too sensitive.

The second attempt was a little better (I didn't know how much to change things), but the shifts were still too hard and I made some of the forced down shifts worse than they were in the first attempt. After studying my graphs of the stock shift schedule I think I got it figured out.

The third attempt, as I said above seems to be just about perfect, at least for mountain driving. I haven't driven it too much around town yet with this setup, so I am not going to mess with it for a while now, just drive it and see what other minor tweaks I may need to make. IMO, it's light throttle shifts are still just a bit too firm (tolerable though) and the WOT shifts are just a bit to soft. The scheduling, so far, seems to be right on the button.

Another little tidbit on the mountain driving in the Jeep. The wife had to tell me to cool it a couple times. The Jeep, with Eibach SRT8 lowering suspension and Bilstein shocks/struts handles like it's on rails and, with the 120 hp or so more from my mods, along with the way the transmssion now works, going way faster than I should into and powering out of corners is an absolute blast....but not to the wife. The down side to this was that I did bottom out the suspension a few times on some of the crappier, pot holed roads.
07-06-2020 06:53 PM
90grandoneer WEEKEND (and Monday) UPDATE

As I said in my Post No. 35, I've gotten rid of the "lost communications" codes that were popping up in the FDCM Module and Central Gateway. Everything always seemed to work and my guess was that I either had the wrong modules disabled or enabled as the case may be, or the PCM wasn't communicating its availability fast enough....2-5 seconds. With the 08 PCM, I really don't like the fact that my DashHawk can no longer read the engine oil pressure or the Knock Sensors/Knock Retard. IMO, both of these are critical but there are no PID's for them in the old DashHawk. They were there for the original PCM though.

Over the weekend, I also tinkered with the up/down shift schedules a little.....just minor adjustments. I think I've got the up shifts pretty much the way I want them except for the 3-4 (old 2P-3) hanging in gear (mid-RPM) a little too long. This is probably set like this from the factory as, I think 2P is normally used for towing. I do have the light throttle and WOT 2-3 (2P-3) and the 3-4 shifts set exactly the way I like them. Through second, third and fourth it's now like a really close ratio manual transmission. It gets rid of the old "bog" between 2-3. IMO, this is the best part of the whole deal. I've also had to "tone down" the shift firmness a bit (and will maybe again) as they're now borderline neck snappers. Once I fine tune all of the up shifts a little more, I'll start working on the WOT down shifts. Once that's done, everything should be good to go.

Another thing I tinkered with, using the Diablosport (DS) Tuner, was the WOT fuel mixture. Stock, it was running about 11.5:1 A/F ratio and it needs to be in the neighborhood of about 12.8-13.2:1 A/F ratio for the best performance. I now have it set between 12.8-13.0:1 and it seems to run real strong The reason I used the DS Tuner is because it was easy to do and I am too lazy to try and figure it out using the HP Tuner. It looks like a nightmare on it. Ultimately, if I don't like the way it runs, I can always load the old tune I had on it for years with the old PCM. I think it's getting near time to take it to the drags again. Haven't been to them in about 5-7 years.....used to go all the time.

The MDS is working more like it was with the original PCM now but, because I am running in 6th gear (old 5th gear) on the highway instead of 5th (old 4th gear), the engine, with the cam I have in it, is a little too much below the beginning of the power curve. I may have to end up setting the shift schedules up so it runs in 5th up to about 70 mph. The MDS transition in and out is also a lot smoother than it was with the original PCM. The MDS with the 08 PCM works up to about 34-35% absolute load, whereas the original only worked up to 30-31% absolute load. These are both at altitudes of 2400-3500 ft. elevation. At sea level those percentages would probably be another 3-5% higher......more MDS time yet. I also messed with the idle speed a little and have it about where I want it......cold start about 1100 RPM, going down to 800 RPM and hot idle at 648 RPM.

The wife and I did our little 150 mile trip today down to the Snake River and 3 Island Crossing State Park. Today was the first time I filled it up and reset the EVIC and my GPS since installing the new PCM. Outbound is a lot of somewhat up-hilly terrain and the temperature was about 74 degrees. I also did no fewer than 8 WOT runs from about 60-100 mph and another two from about 0-100 mph. EVIC fuel economy on arrival was 21.4 mpg. I didn't fill up for the return run, but did reset the EVIC. The return run was about the same, except down-hilly at 88-89 degrees and I only did two WOT runs from about 60-100 mph. The EVIC read 22.6 mpg when we arrived, which is more in keeping with what I usually get. When figured with a calculator the actual round trip (with about 5 miles of city driving) fuel economy was 21.1 mpg. When we used to make this same trip running in 5th (the old 4th) the mileage was almost always between 21-22.5 mpg. So, I think I'll drive it a little more using 6th for a while before I decide if I need to set it to run in 5th at highway speeds. I feel a few more trips coming on.
07-03-2020 02:48 PM
caulk04 I have no idea how the evic is calculating economy. Mine is still pretty close, I average 15. Haha!
07-03-2020 02:03 PM
90grandoneer I think you were right. I found it and changed it from 1500 to 1200 RPM. When I started it this morning the RPM was lower than it had been.

I've "finally" gotten rid of all the PCM codes, but am still getting "stored" loss of communication codes, U0100, U0101, and U0114. They don't seem to affect anything, as now everything seem to work fine. I just made FSM copies of the troubleshooting for these codes and will investigate when I get a little time. If they've not causing a problem and I can't find the answers, I'll probably just leave them alone. I think it's just one thing (maybe the PCM) that's causing them because it appears they're all on the CAN C bus.

Do you have any idea where the EVIC gets its fuel economy inputs from? I advanced the low RPM timing and retarded the higher RPM timing a little more (still getting a little too much KR at higher RPM) and we went for a short ride this morning.....Interstate and in town. The EVIC fuel economy was higher than it was the other day.....up to 27-29 mpg which I am pretty sure is not possible. I also noticed that, on the highway, set up this way, the MDS is on even more than it was the other day. On Monday, I'll fill it up and we'll go on about a 150 mile trip (another one we do quite often) and I'll hand calculate the fuel economy on that when we get back and fill it up again. I am wondering that, if the EVIC information comes from the PCM, something may be calibrated differently than the 06 one.

I am also going to look at some of the transmission settings on the NAG1 and see if there may be some correlation with the 545RFE that will allow me to make similar modifications to the various settings on it. Would be nice to make the shifts as nice as they are on the 545RFE now.
07-02-2020 09:10 PM
caulk04 I tried all his settings as he said them, some I've kept and others I've brought back a bit. So many revisions that I don't know off hand.

I forget which table I changed for the start up idle, but it was a simple one with only a few data points in one column. 'max idle set point' rings a bell.
07-02-2020 07:08 PM
90grandoneer I fixed the misfire issue. It was one of my Sultans of Spark (SOS) coils. I swapped No. 6 with No. 2 and the problem moved to No. 2. Glad it was something simple. Fortunately I had a spare coil. I've also used the HPT forum reference that caulk04 pointed me to and have set the pressures and other settings up as indicated in the thread. It is soooooo much better than the way I had it before with the 06 PCM/TCM......and I thought that was really great. All of the up shifts are lightning fast and the firmness is perfect. I also, modified the DS93 tune (engine part) a little more and will try it out tomorrow. If all is well, then I'll start working on the up and down shift schedules. I will say that the guy on the HPT forum that figured all this stuff out really a genius. If not for his post over there, I know I'd never come close to getting it working the way it does now. I am really loving the six speed too now that 2P (now 3rd) is inserted into the normal up shift pattern when in Drive. Caulk04, have you tried setting yours up like that yet?

Also, I tried to get the cold start fast idle to slow down a little but, I don't think it's working. I tinkered with it again this afternoon and I'll try it again tomorrow morning.
07-02-2020 10:46 AM
caulk04 You'll definitely be changing shift points. The 4-5 (I still say 5th is top gear) shift has kind of a wall where if you're in the throttle at all it won't do it. Totally mapable.

The lockup ramp speed doesn't have a parameter we can see but you can change the pressure and the command point to help that long slide into lockup.

Start small to get comfortable, save each tune as a new file so you can go back if you don't like a change or it messes something up (I've done it).
07-02-2020 09:28 AM
Toddmod I've been paying close attention to my 08 shift scheduling, and with it's shift feel manners. The only thing I'll be looking to change is the lock up command if possible? I don't want it percentage sliding in, lets ramp that up or shorten the apply interval. Another thing I've noticed is at speeds above 60 cruising it doesn't necessarily like going to 6th gear until almost coaxed at like 75-80!!?? I just noticed the other day on a trip that I had to let off the gas to manipulate it to shift into 6th? But it holds it fine. There's something there that needs tweaking! At 80mph in 6th my tach reads 2050rpm- love that! I have larger tires. I'm headed towards the trango sk and HP auto 6 speed soon and I'll go from there. I would love to not have to select 3 to get 2p every time!
07-01-2020 07:09 PM
90grandoneer I am glad I didn't start messing with any of the engine or transmission setting with this PCM/TCM swap yet. Today, the wife and I took a little 60 mile ride to see how it worked on the highway. The 2008 PCM/TCM is stock, except for a modified by me, Diablosport (DS) 93 octane tune with the timing retarded 4 degrees and a few other minor tweaks. Anyway, the route we went is the same one we've done many times with the Jeep the way it was setup before. Here's some what I think are pretty cool observations that can only be attributed to the new PCM/TCM or the DS tune, or both.

--When the engine is cold, the MDS doesn't start working as quickly as it used to, but when it does, it stays on longer than with the other PCM.....old one worked below 31% absolute load, the new one works at 34% absolute load or below which means I am getting more MDS time than I was getting before. On this route, and anytime on a level or slightly hilly highway, the MDS would be active more than 90% of the time. I also noticed on one slight hill that the MDS used to shut off on about half way up, now it stays on all the way up the hill.
--Since changing to the 2008 PCM/TCM, I've started getting misfire codes which I hadn't gotten in a long time.....almost a year since the last one. Now, from cold engine to warm engine the it seems to work fine but, if I turn the engine off and then restart it, within about a mile the misfire code will become pending, but I never, ever feel any misfires. If I reset the code, and drive normally (that's tough for me to do), the code will not reappear. I'll be pulling the plugs and check things over anyway, hopefully tomorrow.
--Now for the good stuff on our short little trip. Again we do this jaunt all the time to go to breakfast at a really neat truck stop about 30 miles away. Today, going outbound (no wind and about 60 degrees), driving at 65 mph, the EVIC showed 21.2 mpg when we arrived. I usually get between 20-23 mpg figured with a calculator, and usually a little lower or higher than actual on the EVIC, depending on driving conditions and amount of MDS on time. On the return trip, still with no wind and about 63 degrees, the EVIC read 24.5 mpg when we got off the Interstate. I am sure these are not the actual mileages but, if it figures the same way it always has, it's probably still somewhere around 24 mpg on the return leg. I've only gotten over 24 mpg, figured with a calculator, a couple times prior to this. Anyway, I am going to pretty much leave the engine tune alone, (just fix the misfire) and not mess with the transmission as much as originally planned, at least not right now. With the HP Tuner I'll firm up the shifts and change the 2-3 up shift, which is really 2 to 2P up shift now that it's a 6 speed. The stock 2008 PCM/TCM has the shift from 2-3 almost immediately after the 1-2 shift and sometimes you can barely feel it has shifted, as there is only about 300 RPM difference between 2nd and 3rd. After doing these few things, I'll just drive it for a while and do some real mileage checks and see if it is for real. I'll also make mental notes on other little tweaks I may want to do down the line.

When we got home, I also put my scanner on it like I've been doing every time I drive it since I changed the PCM/TCM. I guess the vehicle has decided not to reject the new one, as I am no longer getting the code that says there is an "ECU mismatch". Now I am down to basically one code....the pending misfire.

Gotta say, this is starting to be fun.
06-30-2020 11:49 AM
90grandoneer Just a little side note for you guys that tow stuff, you'd probably really love this little mod.
06-30-2020 11:46 AM
Originally Posted by Toddmod View Post
Wow, This is deep!! I will be printing this info for my notes!! Hp tune bound! Bring on auto 6 speed for my 08. I have a bunch of catching up to get where you guys are but 1st things 1st. I have the engine tweak 1st then I'll be picking your brains to tune that! Maybe I'll attempt the enable 2p option will I'm waiting on all my parts though. Thanks guys
Don't feel bad, I've had my HPT for over a couple years now and caulk04 is way ahead of me already, and he's only had his for a month or so.
06-30-2020 11:10 AM
caulk04 Turning on the '6spd' is easy. That picture I have the arrows on...

Click the button that says 'Trans' with the little gear. That will open the window you see with arrows over it. Under the 'General' tab you'll see a switch for 2-2p enable. That's it. From there you can do endless playing with everything else.
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