Is one better than the other? Meaning are there advantages to the 65REF versus the 545RFE transmission? This would be for an automatic tranny behind a 4.7HO engine.
















x speed tranny. But the 545RFE tranny has the same 1 and 5th (6th) ratios. In fact, the 545RFE has all the same internal ratios IF you consider the 2nd gear kick down ratio the same as the 3rd gear in the 65RFE. So to connect to a 4.7HO V8 is there any reason to chose the 65RFE over the 545RFE tranny?

Looks like some of the info you provided is missing.
I probably can't help much on your 4.7 transmission choices, but someone can, might get more answers on the truck board then here.

Going off memory and I'm not sure if this is 100% correct but, I believe the 45RFE, 545RFE, and 65RFE is the same transmission. The biggest difference between them is the programming of forward gears and computer modules. The 45RFE was a 4 speed automatic but, technically it had six forward gears. For example, on the WJs 2001 Jeep Grand Cherokees first used went to the 545rfe that year but, Dakota Dakota and Ram 1500s went to the 545rfe in 2003 but, was 45rfe prior. On 2004 Ram trucks I believe the computer for the transmission was integrated where 2003 trucks trucks had computer module separate. I'm not sure about the later trucks as the Dakota went to a new platform in 2005. Here's a YouTube video that gives a little more information. https://www.youtube.com/watch?v=0OYf2_MS4nA

i always thought the higher the number, the more torque the transmission could take.
similar to the 46, 47, and 48 rh and re transmissions.

Thanks for the tips. I did some more net digging and yes the 45RFE, 545RFE and 65RFE are essentially all the same transmission, different programming. In fact the 45RFE can be changed into a 545RFE just by changing the TCM. The "5th" gear is actually the 2nd-kickdown gear already in the 45RFE. The 545RFE and the 65RFE actually share all the same ratios except for the 2nd overdrive in the 6-speed 65RFE.

Thank you for sharing. That's what I was thinking. The weakest link of the 5-45rfe is the 2nd gear prime if it's been beat on regularly but, my personal experience. I owned a Ram 1500 4x4 4.7 with 5-45rfe for 15 years. I bought it used with 21k miles on the odometer. The transmission never gave me any issues. I put 170k miles on it and did only two filter changes since most of that mileage was rural and highway driving. I did two several times with it and I did have a lead foot at first when I owned the truck but, the transmission was still good when I sold the truck with 190k miles on it.

Dug a bit further into the tranny choices, and the new ZF8-HP would be a great choice, but it is a match to the 4.7. Biggest difference between the 65RFE and ZF8-HP is the lowest and highest ratios, and that the ratio changes in between gears is much closer. Yet the top gear ratios are comparable: 6th in the 65REF and 8th in the ZF8-HP are the same at 0.67. 1st in the 65RFE is 3.00 while 1st in the ZF8-HP is much higher at 4.71. So the ZF gives better off the line power and smoother power with less ratio change between gears. But for steady highway driving they're the same.

However, since the 545RFE and 65RFE are basically the same transmission gearsets wise, could a 545RFE be updated to a 65RFE with a TCM and torque converter change? Would an aftermarket convertor be a good upgrade into a 545RFE?

I can't answer your question. From what I've seen the bolt pattern is different between the 4.7L and 5.7L Hemi. The transmission might bolt up except the one in the 3 o'clock position. The other issues is getting a controller and PCM to control shifts. To be honest you would still better served for now just sticking with the 5-45rfe and worse case some 3.92 or 4.10 gears unless you want to go to 4.56 gears. As far the converter I'm not sure. Back in the day I think Sharadon? Performance in MN/WI use to build 5-45rfes for a while. Not sure if they still do.