[andyvh1959]

The RAM 1500 with the 4.7V8 also used the 65RFE six speed automatic tranny. Assuming the bell housing mount to the 1500 4.7 is the same as bell housing mount for the 4.7 in a DAK, can a 65RFE tranny be installed and work properly in a Gen III Dakota? Would the TCM for the tranny from the original chassis also work if installed into a Dakota. Or does the engine PCM also talk to the 65RFE TCM in such a way that the 65RFE only works if it is also identified to the original engine/PCM that the tranny was mated to in the factory?

 

[Primus]

This has not been talked about much because that model was a one year only offering and not many were made as most went with the 5.7L HEMI. The thing with the RFE series transmissions is that the number of gears is all software set up. The first iteration of this transmission was in the 1999 Jeep Grand Cherokee and was a 4 speed. The next year, the RFE was a 5speed. The Durango/Dakota received the 4.7/RFE in 2000 as a 4spd. only, but by 2002, had the 5spd. programming. According to Allpar's technical section on this transmission, it was designed to one day be an 8spd. but the ratios were not going to be useful.
Technically, the same principle as the 01/02 Dakota's/Durango's going from the 4spd. to the 5spd. could apply here, but one of the issues I see is the BUS comms may be different, as I believe the later Ram 1500's were running a 56 tooth tone ring NGC or something, I have not looked into it lately myself. I think it would be awesome to see what a 6spd. RFE with the 4.7 may be the future for some of us, especially when doing the HEMI swap.

 

[andyvh1959]

Thanks for the info. A bit more net searching and I found that the 45RFE can perform just like the 545RFE with only a TCM change, pretty cool. But I think the 65RFE is a bit more than just a TCM change, not sure. Like you say it may involve different communication on the BUS. Would be awesome though if someone could make a 65RFE perform with the 4.7 in a way to get 20+ mpg on the highway.

I once had a 2006 Ford Explorer for a company vehicle. It had the 5.0V8 teamed with a 6-speed automatic. On the highway at steady 70 mph and fairly flat terrain that bog ol 300hp V8 was getting 24 mpg, I think with a 3:55 rear axle ratio or slightly lower. Pretty impressive.

 

[Primus]

It's hard to say whether if just the software change is all that allows the 6spd. to be accessible on the older RFE's, as the fact the transmission is still the same and there was not much changed internally from the first model year they were available to the last year before the ZF 8HP became the only automatic in the Ram's, Durango's, and the JGC's.
You will probably have better luck looking into this from the factory service manuals for the years the 65RFE was available, then start comparing connections and then the BUS comms to see if the Dakota's and Durango's with the RFE can work with these.

 

[andyvh1959]

It's hard to say whether if just the software change is all that allows the 6spd. to be accessible on the older RFE's, as the fact the transmission is still the same and there was not much changed internally from the first model year they were available to the last year before the ZF 8HP became the only automatic in the Ram's, Durango's, and the JGC's.
You will probably have better luck looking into this from the factory service manuals for the years the 65RFE was available, then start comparing connections and then the BUS comms to see if the Dakota's and Durango's with the RFE can work with these.

My goal is to use my 2001 Dakota as the frame/drivetrain/interior donor for the 56 C3 pickupI bought. My Dak has a 5spd manual but I'll go with the automatic 5spd or 6spd, maybe with a 3:21 rear axle ratio. I plan to use a remanufactured 4.7 HO long block, with headers and TB updates to get over 310 crank HP. Plenty enough for my driving. If that ZF tranny would connect to the 4.7 I'd consider that for sure.

 

[Primus]

My goal is to use my 2001 Dakota as the frame/drivetrain/interior donor for the 56 C3 pickupI bought. My Dak has a 5spd manual but I'll go with the automatic 5spd or 6spd, maybe with a 3:21 rear axle ratio. I plan to use a remanufactured 4.7 HO long block, with headers and TB updates to get over 310 crank HP. Plenty enough for my driving. If that ZF tranny would connect to the 4.7 I'd consider that for sure.

That last part might be a stretch, as the ZF 8HP was only put behind the HEMI's and Chrysler has not done the separate PCM/TCM thing since the early 2000's. It will bolt up to the 4.7, but running both is possibly impossible, unless you can find someone that does standalone controllers like through MegaSquirt to run the transmission with the 4.7, but that may end up not run right with the 4.7 PCM not seeing the TCM inputs or transmission sensors.

 

[andyvh1959]

Right, I'd assume the same. The biggest difference between the ratios of a 65RFE and ZF 8HP are 1st gear and top gear. 1st ratio is 4:00 in the ZF versus 3:71 in the RFE. But top gear is the same for both; 062, so steady highway speed engine RPM would be the same with either trans. But I wonder if a 545RFE can be updated to a 65RFE with a TCM and torque converter change?

 

[Primus]

That’s the thing I can’t answer, as there is a lot I don’t know about the 4.7/65RFE in the Ram’s to know if just the PCM swap will work with the NGC bus comms Dakota’s or not. If the tone rings are the later HEMI 56 tooth tone wheels, then it may not communicate with the dash cluster.

 

[Zaan]

Here's a link to a very good read all about the 45/545/65 RFE transmission.

Strange Transmission: The 45RFE - Legend Magazine

The Grand Cherokee (WJ) had many innovative features, not the least of which was a brand new four-speed automatic transmission with five speeds.

www.legendmag.co.uk

 

[andyvh1959]

Interesting info. I'll have to study more to determine if the 545RFE or the 65RFE is the right trans to work with my 4.7 engine build. Plus, I plan to use either an American Shifter or Lokar floor console shifter for both auto and manual shifting control.