Replace 65RFE with 66RFE - 2013 Ram 1500 2WD

I have a 2013 Ram 1500 2WD Sport that I bought new in 2013 and has around 166K mi on the transmission now. I wish I would've waited 6 months for an 8-speed but I needed a new vehicle and no dealers had any 8-speeds in stock early 2013 MY.

Background: Truck has been daily for the past 8 years and has been a great truck, all things considered. Last year I started adding mods, out of necessity and once started, I couldn't stop - been able to hold off several years. I had a Vararam from a few years ago since the factory clips on the stock airbox broke but was stock otherwise. I had lived with the exhaust manifold leaks for a while but finally repaired those and while I was in there, added some ARH 1 3/4" LTs with catted y-pipe. I had a hemifever tune on it, added an ARH cat-back due to some rattles in the factory exhaust, etc. This last summer I had a tick develop and oil life reduce drastically - ended up having a seized lifter roller. Instead of simply repairing the top end, the engine was tired and the rings were a bit loose, I opted for MMX's 392 with mild NSR cam, ported 6.4 manifold, etc. The local tuner used HP Tuners but didn't really tune it that well - they are used to the cars and the tuning on these trucks (GPEC2) is very different (?) but I have access and ability to edit everything. While the engine was out, went ahead and put in a ~3200 stall. I knew the transmissions wouldn't last long in this configuration but I figured if I babied it I could at least get a year or so out of it, but I only have 3 weeks in it with the new engine, making about 420 at the wheels (heavy 22" hellcat replicas in 3rd gear) and I go into limp mode anytime I need to get into OD gears with the dreaded P0734/P0735 codes.

I would love to attempt an 8-speed swap (or any custom setup) but we just sold our house this past summer and are in the process of buying land and building so we are in a rental and I cannot attempt anything too crazy until I have a shop again.

I don't like the idea of putting another 65RFE back in due to the weakness of the OD clutches and the special driving requirements needed to make it last (no WOT downshifts). I also hate the gear spacing of the 65RFE and I am looking at different options. I have read about PCM issues when trying to use other transmissions like the 66RFE but with what I see in HP tuners (see attached screenshot), 66RFE is a selectable transmission from the Trans Type drop-down and it would appear that the trans gear ratios are editable? What am I missing that makes this swap undesirable - is there more to it than selecting the trans type, updating the gears, and enabling the 2-3 shift, from the PCM perspective? I assume I would need to take it a transmission shop for the relearn process or something...?

I have been researching the internet for months on transmission swap ideas, any guidance or help is appreciated! I am still learning all of the jargon and abbreviations within HP Tuners - I apologize in advance.

yes, the rfe65 is crap.
I think about changing but for 4wd theres more than a simple swap and Software.
Higher rpm, 3rd enable, other shift Points, no shift reduction and some tcc settings will help a Little bit.

Attachment 105507

But is it as easy as adjusting some tuning parameters for the 2WD crowd or will it not work? When I see posts in the past about adjusting the PCM for various transmissions, they always say it can?t be done and it isn?t supported and since I am new to HP Tuners, I don?t know if these options I?m seeing are new (making it possible) or not.

there is an option to change the tranny in the soft .
the drop down menue shows the 66.
so you have to change the ratios and look at a 66 file to be sure that the tcc settings will work.
I think it may work.

I think I?m going to give it a try and see what happens

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Originally Posted by 1SLwLS1

I think I?m going to give it a try and see what happens

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Did You Ever Put A 66RFE In Your 65RFE Vehicle. Was It As Simple At Changing Gear Ratio Values To 66 And Selecting 66RFE And 2Prime Enable? I've Got A 545RFE Jeep That I'd Like To Swap To The 66RFE And Built It Once My 545 Bites The Dust. (Or Build My 545 With 66RFE Geartrain But Would Probably Be Cheaper To Just Get A Complete Used 66)

So I tried but the truck didn't recognize it; I was told that the solenoid pack is a likely culprit but didn't want to dump more money into that experiment. Oddly enough, when I ended up rebuilding the stock 65RFE, it also had solenoid pack issues (different builder used wrong solenoid pack).

I ended up going with an 8 speed swap (still in process) and will be using a harness from Sound German Automotive and his works by essentially telling the factory PCM that it has a manual transmission (like I attempted with the 66RFE) and doesn't process any signals received from the transmission and uses the factory 8HP TCM. So I still think in theory, it should've worked, but I may've had a bad solenoid pack.

resurrection of an old one,sorry. Aside from the solenoid pack issue, did you have any trouble with the drive shaft mating to the 66? I'm trying to confirm mating of spines in the 66 to my current drive shaft, The final puzzle piece is the housing shaft and spines. Ive acquired a free 20,000 mile 66 unit from 2017 2500. From the bench testing i am able to do the software side i got figured out. I hope with carefully planed check marks I can make this swap when the weather gets nicer in a matter of a couple hours. Thanks for your time.

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Originally Posted by Churst$

resurrection of an old one,sorry. Aside from the solenoid pack issue, did you have any trouble with the drive shaft mating to the 66? I'm trying to confirm mating of spines in the 66 to my current drive shaft, The final puzzle piece is the housing shaft and spines. Ive acquired a free 20,000 mile 66 unit from 2017 2500. From the bench testing i am able to do the software side i got figured out. I hope with carefully planed check marks I can make this swap when the weather gets nicer in a matter of a couple hours. Thanks for your time.

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You need a yoke from a 66RFE. I hope you get it working, 8 speed swap still in progress.

Quote:

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Originally Posted by 1SLwLS1

You need a yoke from a 66RFE. I hope you get it working, 8 speed swap still in progress.

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Thank you sir. I suspected this to be the case. Now i can source a yoke ill have it all laid out and ready. Ill come back here with a pictorial or something for future swapers info. once again,think you sir.

Hey Churst get anything figured out? I?ve been wanting to do this as well. Was working with a guy on how to do it but he died last year and still trying to figure things out. Really want to replace my 65rfe with a billet built 66

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Originally Posted by Ramman490

Hey Churst get anything figured out? I?ve been wanting to do this as well. Was working with a guy on how to do it but he died last year and still trying to figure things out. Really want to replace my 65rfe with a billet built 66

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If it is a 2wd it should be pretty seamless. The valve body casting and electronics are identical between all the RFE transmissions other than the 19 and newer 68RFE. 4x4 is where it would get a little interesting, but I still think it is totally possible. I intend to do the swap on our 13 shop truck, but want to prove a few things out with the 65RFE first.

Im in the same boat. Im looking to put one in my 13 sport. Trucks on 37 tires with a 9 lift and 4.56 gears. Im gonna be building a 396 stroker for the truck and don't want the trans to be my weak link. Truck has the electrically controlled Borg Wagner 44-44 t case (which I want to keep) I have the electronics for the 66 swap. I just cant figure out how Im gonna connect the 66 to my bw 44-44 t case. As the output shafts on 65 and 66 input drums have different diameters and lengths. Any info or insight you have would be much appreciated

Quote:

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Originally Posted by Ramman490

Im in the same boat. Im looking to put one in my 13 sport. Trucks on 37 tires with a 9 lift and 4.56 gears. Im gonna be building a 396 stroker for the truck and don't want the trans to be my weak link. Truck has the electrically controlled Borg Wagner 44-44 t case (which I want to keep) I have the electronics for the 66 swap. I just cant figure out how Im gonna connect the 66 to my bw 44-44 t case. As the output shafts on 65 and 66 input drums have different diameters and lengths. Any info or insight you have would be much appreciated

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Have you looked at https://nextgendiesel.com/collection...smission-parts ? FYI, I don't know these people at all. just looking for reviews/advice

Yeah I?ve looked into them. Not much help on the conversion. Everyone say 8 speed swap it and that?s not what I?m looking to do. For the purposes of my truck the 66 would be the better set up.

Following for future knowledge. I have a 2011 Dakota and can't stand the ratios of the 545. Would love to get the 66 in there instead.

Quote:

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Originally Posted by Ramman490

Yeah I?ve looked into them. Not much help on the conversion. Everyone say 8 speed swap it and that?s not what I?m looking to do. For the purposes of my truck the 66 would be the better set up.

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You can swap to the 44-46 electric shift transfer case with Alfo OBD, that will get you the right shaft length and spline count for the trans side. The process will be similar to swapping to a 44-45 found here:
https://www.ramforum.com/threads/bw-...5-swap.132570/

After that it will just be a matter of the drive shafts and a segment swap in the tune for the trans. I suspect we could just alter the ratios in the general tab, but I feel like that would just be if you cannot find the right OS to do a segment swap with... This is of course theory at the moment for us 4x4 guys, like I posted earlier, I will be doing this eventually in my 13 ram. But right now I am going to be proving out the 65rfe in my truck right now to see if there's more holding capacity in my HD Street units than what I have listed on my site. After that I really want to see what sort of changes to performance and daily driving we see from the 66 swap with the better ratios.

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Originally Posted by rodslinger

Following for future knowledge. I have a 2011 Dakota and can't stand the ratios of the 545. Would love to get the 66 in there instead.

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is your truck 2wd or 4x4?

Never heard of a segment swap being a possibility on these trucks. GM?s/Chevy?s yes, Rams no. Like I can?t just take a 2018 68rfe transmissions section of the calibration and drop it into a 2012 68RFE calibration. So much of the coding would actually need to be reworked just to make it work and I don?t think the gas Ram trucks with the 65RFE/66RFE are any different

Quote:

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Originally Posted by Jim P 2.0

Never heard of a segment swap being a possibility on these trucks. GM?s/Chevy?s yes, Rams no. Like I can?t just take a 2018 68rfe transmissions section of the calibration and drop it into a 2012 68RFE calibration. So much of the coding would actually need to be reworked just to make it work and I don?t think the gas Ram trucks with the 65RFE/66RFE are any different

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I know that hydraulically all RFE units 99-18 are the same with only the 19 and newer 68s having some changes in the lockup apply circuit. I'm quite familiar with that side as I have built thousands of them and design parts for them. I've been working my way into tuning them the last couple years now, so I am still learning, that I will readily admit. I am sure a lot of the operation in the coding is very similar, but the biggest thing we would run into would be ratio error codes if making the drop down and ratio changes for a 66/68 in the general tab don't work.

Only reason I mentioned segment swap is knowing that we have to do that for 4L80E swaps where doing those changes in the general tab are not enough in the GM trucks. And being that we have to use files from the same controller and OS I doubt one would be possible to go from a CM2350 to a CM2200. I am talking about theoretically a file from a NGC4 or GPEC2 for a 5.7 powered 2500 to go in our 1500s. I have a couple base files from each that I have tuned so far, which is handy in case we need them.