News on 4.7 8HP Swap

[TheEnder]

Hello everyone,

Recently i made a thread on swapping the RFE in my truck out for the 8HP70.

I contacted russell @ SGA and he told me that since my truck is a 13 that they came from the factory with the 8HP and that the harness from them isn’t needed for the swap if i feel as though i can wire in the trans and shifter myself, but if i want it as close to factory as possible that i can get the harness from them which is the way i want to go. Harness is 1K, pretty cheap. Expected it to be 2K +.

So, i’d expect a used 8HP70 to be around the 800$ area. Factor in the mounts, new trans crossmember etc with either a 2 piece driveshaft or the OG single piece with the 8HP70 flexplate off the Hemi. I have the wiring for the shifter already in my dash, only thing needed now is the transmission wiring and everything mentioned above. Will probably run into the 2-3K range once i’m done which is again very cheap for what it is. Once i’m done selling old parts i expect to maybe if i’m lucky recoup around 1.5K. I hope this helps any other 8HP swappers in the future, any questions go ahead and ask.

 

[TheEnder]

Update:

Seems like the 4.7L/5.7L crankshaft hole for the torque converter to seat in is the same, for anyone with the 4.7L that wants to do this swap. I am buying all the smaller parts now and then I will be purchasing the big ones in hopes of having the swap ready by mid next year; as my current RFE has started to die.

I just moved into a house and have no internet yet. I will post images of findings on this once i get internet. I will also be documenting everything as I think I am the only one doing this to a 4.7L at the moment.

 

[TheEnder]

Update 12/11/22

Buying all of the needed parts within the next few weeks except for the trans and the wiring harness. I still need to brainstorm what to do with the driveshaft situation but I definitely have the time to figure that out. As the truck is not my daily driver I will be putting it in my garage and removing the transmission, driveshaft that's in it, shifter cabling, current 4.7L/5.7L flexplate, shifter from inside the cab and so on and selling it so I can get the swap done faster as I am going to need the truck badly mid next year. Funny how the wiring harness costs more than the transmission itself, but I am waiting on someone to tell me if I can use OEM parts instead of SGA's 1K harness for the 8HP. Question for anyone reading this that has done the swap, where do you put all of the cables for the shifter and for the transmission? Where does the harness hook into on 2013+ trucks? The PCM? Do you have to remove the dash to run the cabling for the e-shifter?

 

[TheEnder]

This is how much everything will cost minus the driveshaft carrier crossmember, driveshaft itself, transmission, wiring harness, crankshaft pilot sleeve (discontinued - have to find it somewhere else). Same goes for the bolts that bolt the 2 pc driveshaft into the trans, they were discontinued but probably available for purchase on sites like eBay.

 

[TheEnder]

Update 2/14

The swap to the 8HP isn’t possible as according to russell the engine calibration for the transmission is gonna be the hardest thing to do because there were never any options for the 4.7 to have the 8 speed i am guessing.

Not to fret - i do plan on taking out my 6 speed and building it to be the best it can be and i’ll make a thread on that soon too. ATS valve body, some other common fixes, high stall converter, diff rehearing and so on.

Id be more bummed if i didn’t have an 8 speed i already daily drive, so hey!

 

[HemiLonestar]

That sounds like a cop out. Willing to bet the 5.7 calibration would work just fine with some tweaks.

 

[Wild one]

Update 2/14

The swap to the 8HP isn’t possible as according to russell the engine calibration for the transmission is gonna be the hardest thing to do because there were never any options for the 4.7 to have the 8 speed i am guessing.

Not to fret - i do plan on taking out my 6 speed and building it to be the best it can be and i’ll make a thread on that soon too. ATS valve body, some other common fixes, high stall converter, diff rehearing and so on.

Id be more bummed if i didn’t have an 8 speed i already daily drive, so hey!

How are guys putting a 8 speed in the earlier trucks then.The 3rd Gens and early 4th Gens never had an 8 speed. I agree with HemiLonestar.Guys have put 5.7's in where 4.7's have been,and used the stock ECM/PCM to tune them,so you can add the 5.7 programing to your 4.7 PCM

 

[TheEnder]

How are guys putting a 8 speed in the earlier trucks then.The 3rd Gens and early 4th Gens never had an 8 speed. I agree with HemiLonestar.Guys have put 5.7's in where 4.7's have been,and used the stock ECM/PCM to tune them,so you can add the 5.7 programing to your 4.7 PCM

That’s a great point i really didn’t even think about.

Truck already has the brown/white connector solenoid pack the hemis used so i bet with some custom tuning it could be done. Still doing the swap then!

 

[TheEnder]

How are guys putting a 8 speed in the earlier trucks then.The 3rd Gens and early 4th Gens never had an 8 speed. I agree with HemiLonestar.Guys have put 5.7's in where 4.7's have been,and used the stock ECM/PCM to tune them,so you can add the 5.7 programing to your 4.7 PCM

Do you know if you can take off the extension housing on a 4WD 8HP70 and replace it with a 2WD like you can on the RFE? If so i am going to pick up a transmission tonight.

 

[Wild one]

Do you know if you can take off the extension housing on a 4WD 8HP70 and replace it with a 2WD like you can on the RFE? If so i am going to pick up a transmission tonight.

I think you have to totally disassemble it and change the mainshaft to. That's what i've read,so whether it's true i can't confirm.I do know of 1 guy who changed his 4X4 from an 8 speed to a 2 wheel drive 8 speed and he said he had to hunt up a complete 2wd 8 speed to do the swap.