How-To: 45RFE to 5-45RFE Transmission Upgrade - DodgeTalk : Dodge Car Forums, Dodge Truck Forums and Ram Forums

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How-To: 45RFE to 5-45RFE Transmission Upgrade

06.08.2014 - New information added at the end of the thread

45RFE to 5-45RFE Transmission Upgrade
2002 Dodge Ram 1500 with the 3.7L and 4.7L Engine

Everything written here is my personal experience and the steps I took with my personal truck. My truck does not have any warranty and I alone am responsible for the repairs and upkeep. If I step in it, I have to clean it up. That said I’ll try to be very careful what I do to my truck and research everything before I do something major to the truck. I can’t afford to do the job two or three times because I was brain-dead, thought it would work, or it looked cool at the time. I do not have a money tree in my back yard and I don’t have money too burn. So when I find something that will help me save money short-term, as well as, long-term, I like it.

Back Ground on the Modification

An 45RFE transmission updated to the 5-45RFE on the cheap; I had read DodgeTalk (DT) threads on the 3Gen Ram Forum that claimed you could flash the Transmission Control Module (TCM) but no one had been able the find a dealership or tech that would try or even help with this odd mystery. After doing some searching and lurking in the 2Gen Dakota forum, I found a few threads that claimed you could update the 45RFE transmission to a 5-45RFE with the TCM and there were Dakota DT members that had done the update. It was easy; you started by purchasing a used 2001 or 2002 Jeep Grand Cherokee TCM then have it checked and updated with the 2002 Jeep flash for the 5-45RFE. You then place the TCM on the Dakota and bam, you’re done. The claims of firmer, better shifting with a 300 to 400 drop in the RPM with better fuel mileage would be welcome news to any of us with a 6000 pound truck. So I read-on and did some more research.

Could this 2Gen Dakota update to the TCM be done on the 2002 Dodge Ram 1500? One long time Mopar technician and DT member (mprtech) said yes so long as the ‘02 Ram had the 3.7L or the 4.7L engine. So there have been a couple of 3Gen Ram owners that were willing to be the guinea pigs and try it first.

What You Need To Know

There’s two ways of achieving this goal. The first method, you remove your Dodge TCM and send it off. You won’t be able to drive your truck without the TCM, so plan on some down time. Your TCM will have the software changed, flashed for the 5-45RFE, and then you’ll just reinstall it onto your truck. This method is less costly and less time consuming but if you have gremlins or problems, it could be more costly in the long run trying to iron out the problems. I haven’t read of one Dakota owner having problems but the TCM upgrade is untested in the Ram’s.

The second method is the path that I’ve chosen to follow. I went this way because I didn’t want my truck disabled while I was waiting for the Jeep TCM to show-up the mail. Plus I have the added benefit if there’s a problem I still have the original Dodge TCM on hand during the trouble shooting; no down time. Yes, I had to order the Jeep TCM and wait for it to show-up in the mail only to send it away to be reworked and then have to wait yet again for it to get home. It took one week to receive the used Jeep TCM, one week to send it away to be reworked, and one week to finely receive the finished product. It takes longer but I felt it was the way to go. Besides, I can always change my mind and put my used Dodge TCM in the DT classifies later for someone else to use. But I’m happy because now I have two TCM’s for my truck and I have no worries of my truck breaking-down.

I was told I needed to look for a TCM out of a 2001 or 2002 Jeep Grand Cherokee with a 4.7/RFE package with part number: RL041504AG. I was told the last two letters are VERY important and not allow someone to sell me a TCM with a different letter set. This part number would be the Jeep TCM that would work in my 2002 Dodge Ram 1500. If I had ordered the Jeep or Dodge TCM thru the dealership, it would have cost almost $600 bucks for the new TCM and $175 for the core then they wanted two hours to install it at $85 dollars an hour. I waited until I had left the dealership before I laughed so hard I had to pull over to the side of the road. I found a 2001 Jeep GC TCM with the 4.7/RFE package though the web site and the closest TCM was in Russellville, AR. Once I received the Jeep TCM, I sent it to mrptech and it was checked-n-flashed for me. There are other sources and this is but one example.

This is the front view of the Jeep TCM:

Back view of the TCM:

Side view of the TCM with the ID Tag:

Installation of the Jeep TCM

I started by removing the Superchip Program Tune. I wanted everything to be a clean install. I then got under the hood and disconnected the negative battery terminal.

The TCM is located on the passenger fender in-between the air cleaner and the firewall. The Engine Control Module (ECM) is mounted on the firewall near the TCM. Both share a common wiring harness.

To get to the TCM, I removed the top of the air cleaner box, set it aside, and then disconnect the ECM and TCM. Start with the 8mm bolt that’s part of the wiring harness connector at the TCM. Then it’s an easy pinch of the finger to disconnect the three connectors at the ECM. Lift the whole wiring harness and lay it behind the lower air cleaner box. With that done, you need only to remove three more 8mm sheet metal screws that hold the TCM and it’s free. Set the Dodge TCM aside and install the Jeep TCM. Very carefully, reconnect all three of the ECM connectors with a straight push until you hear and feel it click in place. To reconnect the TCM connector, you need to start the 8mm bolt by hand; hold the TCM connector in place while you thread the bolt with a socket. DO NOT use a ratchet. Remember, this thing is plastic, silicone chips, aluminum, and its worth about $600 to $800 bucks. As you’re tightening the 8mm bolt, it isn’t a lug nut; so tighten it firm but lightly. Now put the air cleaner back together and reconnect the battery.

Well, you’re done. For the first one hundred miles, the computers are going to need time to learn from each other. So it might be wise to take it easy until the truck learns the Jeep TCM software.

My Driving Impressions

Right away, I noticed the shifting pattern was a little firmer and each shift was higher in the RPM ban. It feels like the Jeep TCM is holding onto more line pressure and its helping the transmission hold the gears better. No more of the blasted gear changing in-and-out of OD; YEAH! With a light petal up to 60-mph, I was wondering when the transmission was going to stop shifting. Much of the shifting felt like the difference between a stock Dodge and adding a performance tuner like Superchips. I didn’t have the program tune on the truck at this time and I liked it. I decided to play with the truck and came up with a Driving Profile. I would start the truck out light and work my way up to running a wide open throttle pass up to about 80-mph. The highest speed limit in the area is 65 and one of the roads I used was 35. I thought I might be able to talk my way out of ticket if I was on a lonely patch of road and the officer wasn’t a DPS Trooper. While running my profile there were cops everywhere but I found two spots and ended the day with no tickets; always a plus. The weather didn’t help; it was hot, windy with the dirt blowing, and there was a lot of moisture in the air. I could feel the truck and see on the tachometer when the engine was gasping for air at the higher rpm’s. I include the local weather numbers for those who love to solve air density problems.

Temperature – 93 Degrees
Humidity - 58%
Dew Point – 63 Degrees
Barometer Pressure - 29.92 inches
Winds – 23 from the South
Elevation - 3762’

See if my math is right here. I get a Density Altitude of 7150 feet; a difference of 3388 feet and an altitude that’s almost twice the city’s elevation.

So far I’m seeing about a 2.8-mpg increase in my fuel mileage. With all of the Wide Open Throttle (WOT) runs that I’ve been doing on the highway, I’m pleased with the updated Jeep TCM. I can honestly say this is the second easiest modification that I’ve ever put on my truck; the first was the AIR_RAM Power Wire and Ram Scoop and the second was the Jeep TCM.

One Problem … Maybe

The only hiccup I had was at a moderate gas petal setting during acceleration to enter the highway. I was able to duplicate the hiccup anytime with the stock or Superchip tune. As I was speeding up, the trucks rpm’s were rising and falling in-between 2500-to-3500 rpm’s as it shifted though 1-2 and then 2-3 with no problems. The rpm’s climbed to 3500 then drop all the way down to 1900-rpm’s. The truck up-shifted and felt like it had skipped a gear. The engine felt like it fell flat on its face or it had stalled. Another way to describe it would be like shifting a manual transmission from 3rd gear directly into 5th Gear (OD). It startled me the first time because I was entering the highway and I was afraid I was going to be working on the side of the road exchanging the Jeep and Dodge TCMs. I like working on my truck but not while eighteen wheelers are zipping by at 65 to 70-mph. Since the hiccup could be duplicated, I video taped it and continued down my driving profile sheet. I believe this is simply part of the Jeep software to place the trucks transmission the highest gear as quick as it can to save on fuel; saving fuel is OK with me. The Hiccup Video was the last one shot but I placed it here with the text. (40-seconds) Hiccup -


OK, break out the popcorn; here are the videos. They’re boring but maybe you can see the difference between the Jeep TCM and your truck. I did my best to keep everything quiet so you could hear the engine and the shifting of the transmission. Each video is one to three minute long. The videos are from my camcorder and they are the best of the shots that I took during the day. I did my best to pick the video shots where the camcorder was holding the dash in the center of the picture and with as little glare as possible.

The first is city driving speeds up to about 50-mph with the stock Dodge TCM. Remember: there is no program tune on the truck at this time. (3:18 minutes)

The next video is the same roadway and speeds but with the Jeep TCM installed. (3:05 minutes)

This is the first Wide Open Throttle video. The truck is stopped in the dirt and gravel along the side on the roadway. I pull out and hold it wide-open until it reaches about 80-mph. (1:12 minutes)

This video follows the WOT run the same way but after the truck reaches about 80, the truck is slowed to 45-mph and the WOT is repeated. By doing this, the transmission is dropped down into the 2nd Prime Gear. (1:43 minutes)

For the next part of the driving profile, I have pulled off the highway and installed the Superchip 88-Octane Program Tune. This is the only program tune I will use for the remainder of the videos. Each follow the same driving profile as the last three; City Speeds, then the WOT, and the 2nd Prime.

City (3:06 minutes) -

WOT (1:01 minutes) -

2nd Prime (1:35 minutes) -

Closing Comments

I hope this little “How To” has not been lacking in anyway but has been too much. For one person may need one section while the next may need something altogether different. This whole “How To” thing could’ve been done on a 3x5 card with a few pictures just for color. But I wanted to include some of the research, as well as, the different options you have open to you.

I also want to include three DT threads on the Jeep TCM subject. Each of these threads has information and comments from other DT members that may help you out.

2G Dakota - Drivetrain Talk forum:

3G RAM - Drivetrain Talk forum:

3G RAM - General Talk forum:

__________________________________________________ ____________
6/10/08 Addendum:

Now that I’ve had the Jeep TCM in my truck for two weeks, I thought I would update the TCM upgrade thread.

What I wrote as a possible problem, I believe was the hot humid weather and heat soaking. I believe now that I was hitting the transmission too hard and not allow enough time to pull the heat back out of the truck. I also believe the PCM and TCM had not settled down enough to perform the hard-on testing that I performed that afternoon. I have tried to recreate the "hiccup" but I’ve been unable after seven tries on three different days. I’ve also retested some of the runs and have not seen any difference aside from the smoother, firmer, and more precise shifting. My truck feels like the tranny has been rebuilt. I can’t attest to any difference in the fuel mileage at this time because I’ve left the engine running with the A/C going while I’ve been inside the store a few too many times. All I can say is WOW what a difference. Thanks MPRTECH!
__________________________________________________ _________
08/19/09 Addendum:

OK folks; I have an update for the thread. Some DT members have had problems getting in touch with mprtech and have emailed me for advice. So I’m going to tell you what I’ve told each of them.

Everyone that I know of, expect one person, had the Jeep TCM upgrade done by mprtech and that one person lives in Russia. The shipping and handling to Russia was going to make the upgrade too costly so he found a tech in Russia to do the job. The upgrade is simple but you have to have someone that can do the programming to the TCM. All of the Dodge and Jeep tech’s that I know and work with the TCM programming equipment will not do the job because you’re changing the way the computers came from the factory. The work could open up the dealership to a law suit from Dodge or the Government because the changes alter the way the truck shifts and the way the truck was certified by the EPA before it was sold to you. The tag on the side window with the trucks information and EPA rating is a contract in-between all the parties; the Government, the EPA, Dodge, the dealership, and you – the owner of the truck. I know it sounds like B.S. but that’s why mprtech has been such an angel to us here on DT; he’s been willing to bend the rules a little for us. Personally, I do not see the problem since the 2003 model trucks have the same programming. Why anyone would get upset about upgrading and making the truck more efficient is beyond me. So if you cannot get hold of mprtech, you’re only hope is to find a 2002 Jeep Grand Cherokee or a technician that is willing to work with you on this upgrade. It has to be someone that works on Jeeps because my understanding on the upgrade is this; the Jeep TCM is programmed to the latest flash for the 2002 Jeep GC with the 4.7L engine and the 5-45RFE transmission. I do not believe there’s any more to it but that means the technician will have to have a VIN-number for a ‘02 Jeep. If the tech doesn’t have one, you could give the tech a number from Jeep that’s in a junkyard. If you real lucky, you might find a ’02 GC that matches what you’re looking for and you can just use that TCM from that Jeep. But you’ll have to be real careful that you match what you need with the junked Jeep. After that, it should be a plug-n-play with your truck.

After a few members read my PM's, I had had one member send me a PM with what he had done to his truck.

Ok I got some new information for you I went to and searched for a TCM for a 2002 Jeep Grand Cherokee which had a separate TCM and PCM like our trucks. In order for the swap to work you have to look for the part number 56041905AD this is the jeep that had the 4.7 with the 5-45RFE. Then I just installed it and everything worked just fine and I picked up the 5th gear.

However, in Mississippi it is pretty hilly and it geared me up to high even with the 4.10 gears so I am going to post this one for sale in the classifieds. I hope this new information can help some folks out.

Appreciate the help,

I hope this information helps to answer any questions that you may have about the upgrade.

__________________________________________________ _________
06.06.2014 Addendum:

One of the new TCM threads had some updated information. He said the tech that was doing the reprogramming and posting in the Dakota section was using the coding from the 2004 Jeep GC TCM not the 2002 model year.

"If you used the (56041905AD) 2002 TCM, you don't have to worry. I have also used 2003 and 2004 Jeep TCM's (56044574AC)."

Using the 2004 model year programming may solve the hard shifting problems that some DT members have reported.

I'll add a note here as well. You need to keep your old Dodge TCM handy. Store it safely in your toolbox or something. If there ever comes a time that you have your transmission worked on, you'll need it! After they work on the tranny, you need to have a 'Quick Learn' done at the dealership. How are you going to do that with a Jeep TCM on your vehicle? You take it to the Dodge dealer, they put your VIN number in the computer, and the computer would go nut looking at your Jeep TCM. So you think you'll take the vehicle to the Jeep dealer and what do you think they can do for you? You need to put the old Dodge TCM on the truck, get the work done, have the 'quick learn' done, and then put the Jeep TCM back in place. So save your Dodge TCM just in case!

If you start a thread, be responsible and post the final outcome.

2002 Ram 1500 SLT 4x4 QC ~ 02 Ram 45RFE to Jeep GC TCM 5-45RFE Upgrade - (Nov.01) 4.7L with 91K/3588hrs, 4.56 R&P/DTT, Sonnax Line Booster, SRT-10 Pod w/Dynojet Wideband Commander, 2-speed manual transfer-case, Clifford Security System w/Auto Start/Auto Windows, RB1 CD/DVD/NAV Infinity Sound System w/30GB iPod, Offroad Package, 33" Bridgestone Dueler A/T, Mopar Rear Wheel Liners, K&N w/Airaid Jr Modular Intake Tube, BBK 70mm Throttle Body, AIR_RAM Jet Stream Scoop, PML Diff Cover, ASP Underdrive Crank Pulley, MSD 1.65 Alt Pulley, V8 Lincoln E-Fan, 2-Speed DCC E-Fan Controller, 180 Jet T-Stat, Flowmaster SI/DO Exhaust, Tire-2-Tire Chrome Tuber Step, Line of Fire LED Light Bar, Sylvania Ultra Silverstars

Texas 1845: We the People of the Republic of Texas, acknowledging,
with gratitude, the grace and beneficence of God.

Last edited by dmcelhannon; 06-08-2014 at 04:49 PM.
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