8 speed swap

[1SLwLS1]

Seems kinda anticlimatic.

You can tell from the pic with the transmission crossmember, that the trans mount is a bit rearward of center. It's because the 8HP70 is about 1/2 inch longer than the 65RFE.

That means the transmission mount needs to slide backward an equal distance (and if you're 4x4, the front driveshaft needs a spacer to make up the distance that has now increased by the transfer case being moved 'backward' 1/2 an inch).

Ahh yea, you're 4x4. I don't think us 4x2 guys can modify the 65RFE 1 piece driveshaft so easily, but I could be wrong.

 

[Evguy1]

Does your tow/haul work? I didn't think about if the challenger firmware has a tow/haul mode and I was going to ship Russell my TCM over the holidays.

I have the Challenger firmware and it has a "sport" mode rather than a "tow" mode.
I just programed the sport mode as the tow mode. I wanted the Challenger calibration so I would have full manual mode with my new Challenger console shifter which is very nice for towing in the mountains. Russell's PCS module has a wire for sport mode but I don't know if the stock Tow/Haul button on the RAM will toggle that on.

 

[Wild one]

Ahh yea, you're 4x4. I don't think us 4x2 guys can modify the 65RFE 1 piece driveshaft so easily, but I could be wrong.

You can't use a 1 piece driveshaft with the 2 wheel drive 8 speed,as there's no slip yoke used at the rear of the transmission on the 2wheel drive 8 speeds,so you're going to need a 2 piece driveshaft that has the slip yoke at the carrier bearing

 

[1SLwLS1]

I have the Challenger firmware and it has a "sport" mode rather than a "tow" mode.
I just programed the sport mode as the tow mode. I wanted the Challenger calibration so I would have full manual mode with my new Challenger console shifter which is very nice for towing in the mountains. Russell's PCS module has a wire for sport mode but I don't know if the stock Tow/Haul button on the RAM will toggle that on.

Yea, the sport mode plus gave manual control being able to lock out 7th or 8th should do it.

You can't use a 1 piece driveshaft with the 2 wheel drive 8 speed,as there's no slip yoke used at the rear of the transmission on the 2wheel drive 8 speeds,so you're going to need a 2 piece driveshaft that has the slip yoke at the carrier bearing

Well not a stock one anyway.

 

[HemiLonestar]

You can't use a 1 piece driveshaft with the 2 wheel drive 8 speed,as there's no slip yoke used at the rear of the transmission on the 2wheel drive 8 speeds,so you're going to need a 2 piece driveshaft that has the slip yoke at the carrier bearing

That's what slip shafts are for. No carrier bearing but yes, it's technically a 2 piece but it's one shaft.

 

[Wild one]

That's what slip shafts are for. No carrier bearing but yes, it's technically a 2 piece but it's one shaft.

That works as long as the shaft isn't to long,but in a quad or crew cab truck,the length will give you issues once you get the driveshaft rpm up. That's basically what the after market is using for the regular cab shortbox trucks,but nobody is using a single shaft on the 2 wheel drive 8 speed quad or crew cab trucks,as the harmonics on it would start to be a little hard to control above 5,000 driveshaft rpm,can you say skipping rope.Even the cars use a carrier bearing to offset driveshaft harmonics,and their diffs are solidly mounted

 

[t0ymach1n3]

I have the Challenger firmware and it has a "sport" mode rather than a "tow" mode.
I just programed the sport mode as the tow mode. I wanted the Challenger calibration so I would have full manual mode with my new Challenger console shifter which is very nice for towing in the mountains. Russell's PCS module has a wire for sport mode but I don't know if the stock Tow/Haul button on the RAM will toggle that on.

Are yall using the SGA kit on a 2013+ truck? If so, you don't need that kit at all to do the swap nor have a center console shifter.

 

[1SLwLS1]

Are yall using the SGA kit on a 2013+ truck? If so, you don't need that kit at all to do the swap nor have a center console shifter.

For me, I am lazy and the SGA kit is easy, documented, and well supported.

Do you have a write up for converting the 2013+ trucks without his kit?

 

[t0ymach1n3]

I am writing it up as we speak as i just did the swap on my 2014 in my driveway at my apartment garage with basic hand tools, a jack and all the OEM parts needed to do it.

 

[1SLwLS1]

I am writing it up as we speak as i just did the swap on my 2014 in my driveway at my apartment garage with basic hand tools, a jack and all the OEM parts needed to do it.

Nice, can’t wait to read it!

 

[t0ymach1n3]

Nice, can’t wait to read it!

It's gonna be a read lol. I'm not sure how well it will be received being i've never wrote anything like this in my life and i'm sure i'll leave out some important parts. Also, looking back on it, I wish I would have taken more pictures of the process but I was doing it in a hurry as my 65RFE had taken a dump and I had to get it done asap.

Maybe that's what i'll work on tonight and get at least a rough draft out there.

 

[1SLwLS1]

It's gonna be a read lol. I'm not sure how well it will be received being i've never wrote anything like this in my life and i'm sure i'll leave out some important parts. Also, looking back on it, I wish I would have taken more pictures of the process but I was doing it in a hurry as my 65RFE had taken a dump and I had to get it done asap.

Maybe that's what i'll work on tonight and get at least a rough draft out there.

Well if you leave anything out, I’m sure someone will ask the question and you can just go back and edit, I wouldn’t worry about it. Internet is full of critics and self proclaimed experts, just ignore them.

Make sure to link it back here as it’ll be good relevant information.

 

[Evguy1]

So I have been trying to find a tuner to help me with my one of a kind Cummins 4 cylinder/ZF8HP70 swap. I have tried all the big name and smaller guys. They all declined due to it not being a "normal" tune. The only person who offered to help was Matt at Demon Motorsport but his experience is mostly with gas cars wanting to go fast, he did give me a few tips on tuning and it got me closer to what I needed but not all the way.
Then out of the blue I had a response on the HP Tuners forum from DodgeBoy who said he could help.
Did he ever. He worked with me over the last week to fine tune my trans so the upshifts and downshifts were right were I wanted them. It took a number of tries, I kept sending data logs after each new tune. I was impressed with his knowledge and determination to make it right. Anyone not wanting a stock canned tune should give DB a try, Dodge Boy Calibration 8HP <[email protected]>
Tell him Randy sent you. ;>)

 

[Evguy1]

Are yall using the SGA kit on a 2013+ truck? If so, you don't need that kit at all to do the swap nor have a center console shifter.

I had to use it on my 2014 since the Cummins is not stock in these trucks and did not communicate with the stock ZFHP70 trans TCM, I put a lot of work into my centre console shifter and LOVE it.

 

[TheEnder]

Seems kinda anticlimatic.

You can tell from the pic with the transmission crossmember, that the trans mount is a bit rearward of center. It's because the 8HP70 is about 1/2 inch longer than the 65RFE.

That means the transmission mount needs to slide backward an equal distance (and if you're 4x4, the front driveshaft needs a spacer to make up the distance that has now increased by the transfer case being moved 'backward' 1/2 an inch).

Thanks for this.

The crossmember for the driveshaft was sold out and the seller didn’t care to tell me until after i bought it. Got a refund today so i’m probably just gonna buy everything else and put what i bought in the 4.7 thread i’ve had going for the past few months. I’ll either find a way to fabricate one (shouldn’t be that hard, and i can write up on it) or i’ll just be searching for another one. Will the carrier bearing driveshaft mount from a 2009 3.7L V6 work?

I’m 2WD so there’s no having to worry about the front end needing spacers. I should have the harness for the 8HP purchased within the next few weeks, then i’ll store it in my garage as i buy the flexplate, screws, mounts, etc. Last part will be buying the tranny. I’m considering tearing the truck apart now as i don’t need it for the next few months and selling all the parts on it so i can get the swap done ASAP as my RFEs converter is starting to go out majorly.

 

[TheEnder]

Are yall using the SGA kit on a 2013+ truck? If so, you don't need that kit at all to do the swap nor have a center console shifter.

I’m very interested in this as i do not want a center console e-shifter in my truck, i would much rather the dial. Will this cost more?

 

[HemiLonestar]

That works as long as the shaft isn't to long,but in a quad or crew cab truck,the length will give you issues once you get the driveshaft rpm up. That's basically what the after market is using for the regular cab shortbox trucks,but nobody is using a single shaft on the 2 wheel drive 8 speed quad or crew cab trucks,as the harmonics on it would start to be a little hard to control above 5,000 driveshaft rpm,can you say skipping rope.Even the cars use a carrier bearing to offset driveshaft harmonics,and their diffs are solidly mounted

2004 quad cab 6.1 based 392 w/8HP70:

 

[t0ymach1n3]

I’m very interested in this as i do not want a center console e-shifter in my truck, i would much rather the dial. Will this cost more?

No. Depending on how in depth you go and where you buy parts from, it could very much be cheaper.

 

[Evguy1]

Should be much easier and cheaper especially if the wiring is already behind the dash for the dial shifter. It took a lot of work and wiring to get to this point....but I love it. The storage "pit" that I lost was just a collector of crap so I don't miss it at all. Having manual mode on the shifter is great for towing, lets me drop a gear before a hill and hold the gear till I want to shift.

 

[t0ymach1n3]

Should be much easier and cheaper especially if the wiring is already behind the dash for the dial shifter. It took a lot of work and wiring to get to this point....but I love it. The storage "pit" that I lost was just a collector of crap so I don't miss it at all. Having manual mode on the shifter is great for towing, lets me drop a gear before a hill and hold the gear till I want to shift.

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Your install is super clean! I'm personally going after paddle shifters versus the manual center console shifter. Much more natural feel to keep my hands on the wheel and shift over one hand.