8HP Swap on 2018 and older PW?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Odin

Senior Member
Joined
Oct 31, 2014
Posts
566
Reaction score
373
Location
Arizona aka HELL
Ram Year
2015 2500
Engine
Hemi 6.4L
Anyone on here with a 2018 or older PW done the 8HP swap? I pretty much just read every single page of the 8HP swap on our forum and for the 2014-2018 it's a lot less expensive. Looks like no need for SGA wiring harness and some other things. Still gotta fork out money for the trans and some other parts though. My '18 is almost paid off and my only real complaint is the trans, but not worth another truck payment in trading it it.

Russell at SGA said I should be able to use the ecu and tcm tune from a 2019 PW and if needed he could reprogram my ecu.
 
Last edited:

olyelr

Senior Member
Joined
Nov 18, 2018
Posts
4,674
Reaction score
3,418
Location
Kewadin MI
Ram Year
2016
Engine
6.4
Im in the same boat as you. Love everything about my truck but the trans.

Subscribed!
 
OP
OP
Odin

Odin

Senior Member
Joined
Oct 31, 2014
Posts
566
Reaction score
373
Location
Arizona aka HELL
Ram Year
2015 2500
Engine
Hemi 6.4L
Im in the same boat as you. Love everything about my truck but the trans.

Subscribed!
There's another member on here who posted about doing the swap in his 2014 1500 in his driveway with just hand tools and it didn't require a whole lot. Said he was gonna do a huge write up on it. I sent a PM to see if he got around to completing it.

I'm mechanically inclined to a degree, so I feel I could do it with some help from one of my buddies as far as install of the trans and other related hardware under the truck. It requires a change to the dial shifter which would have to come out of a 2019 PW, but that's not a big deal, it would be easy to install where the Fob or push button is and relocate those to just above like is in the 2019 and up trucks. I found one already on ebay for like $120.

I guess the 2014 and up trucks across the board are supposed to come equipped with being able to run the 8HP if I'm reading a few of the posts in that thread right and a couple things Russell at SGA has put out. I'm just not sure how much is actually there vs what still needs to be bought vs how much the 2013 and older 4th gen guys have to get. I'm not a technically inclined when it comes to wiring, so here's where I'm hoping someone has done/researched it for our trucks a little more.

I know our trucks need the 8HP75 from a 2019 or up PW or 6.4 2500 4x4 with the trans case lever and not the push button 4wheel system. Saw a couple on eBay in the range of 1.8k-2.7k.

Now, what I'm not sure of is, if in that swap to the dial knob, how it would all work with our lockers, sway bar disconnect, and hill descent.

EDIT: Actually, after thinking about it, I don't think we'd need the dial shifter out of a PW. We could use one out of any 1500-2500 that's just PRND and keep our bezel set up like it is.
 
Last edited:

gtomike60

Senior Member
Joined
Feb 3, 2023
Posts
187
Reaction score
161
Location
Milford,Mass
Ram Year
2012
Engine
5.7L HEMI
I'm finishing up the swap on my 2012 and did it all with bolt on OE parts + the SGA harness/controller
I got longer front/shorter rear driveshafts from Tom Woods and I did the install myself in my 2 car garage

Your transfer case will bolt on to the 8HP75 with possibly needing the adapter swapped.Just make sure you get the trans from a 2500/3500 for the 29 spline output vs the 23 spline on the 1500
I had to elongate a couple of slots in the crossmember and the mount dropped right in
Transmission has nothing to do with the function of the lockers or sway bar unless it's all integrated into the same dial on your newer truck,but you could get one from an 8 speed PW,and you'll have to get an 8 speed shifter anyway

All in,I'm at $4900 ready to run,including the driveshafts,with me doing all the labor
 
OP
OP
Odin

Odin

Senior Member
Joined
Oct 31, 2014
Posts
566
Reaction score
373
Location
Arizona aka HELL
Ram Year
2015 2500
Engine
Hemi 6.4L
I'm finishing up the swap on my 2012 and did it all with bolt on OE parts + the SGA harness/controller
I got longer front/shorter rear driveshafts from Tom Woods and I did the install myself in my 2 car garage

Your transfer case will bolt on to the 8HP75 with possibly needing the adapter swapped.Just make sure you get the trans from a 2500/3500 for the 29 spline output vs the 23 spline on the 1500
I had to elongate a couple of slots in the crossmember and the mount dropped right in
Transmission has nothing to do with the function of the lockers or sway bar unless it's all integrated into the same dial on your newer truck,but you could get one from an 8 speed PW,and you'll have to get an 8 speed shifter anyway

All in,I'm at $4900 ready to run,including the driveshafts,with me doing all the labor

I'm not sure if you saw my edit on that second post. But afterwards I got to thinking about the shifter and realized I don't think a PW specific one would be needed. My initial thought was the parts needed had to be PW specific. My comment about the lockers/sway bar was if one of those specific units was used, because they changed it in 2019 where all that stuff was put into the dial unit vs the 2018 we have it as part of our radio bezel surround. I'm pretty sure a dial out of any 8 speed truck would work. I had read in that thread Russell was trying to figure out how to keep the column shift and idk if he ever did. If so, that's one less thing for us to have to worry about swapping out. But if not, would make modifying the dash to accept the shift dial much easier if it was just the PRND without the additional buttons.

Appreciate you chiming in. I posted in that thread a week or so ago when I read a large majority but not all and never got a response.

Out of curiosity, why'd you get longer drive shafts? I know in the thread someone said the 8HP is like an inch longer than the RFE and it sat back further so a spacer was needed. But then someone came along and said it wasn't.
 
Last edited:

GTyankee

Senior Member
Supporting Member
Military
Joined
Nov 2, 2020
Posts
10,061
Reaction score
12,607
Location
El Cajon Calif. 92021
Ram Year
2016
Engine
3.0 ecodiesel
Don't some Jeeps have the 8 speed & 4 x 4
no Rotary knob
 

gtomike60

Senior Member
Joined
Feb 3, 2023
Posts
187
Reaction score
161
Location
Milford,Mass
Ram Year
2012
Engine
5.7L HEMI
I'm not sure if you saw my edit on that second post. But afterwards I got to thinking about the shifter and realized I don't think a PW specific one would be needed. My initial thought was the parts needed had to be PW specific. My comment about the lockers/sway bar was if one of those specific units was used, because they changed it in 2019 where all that stuff was put into the dial unit vs the 2018 we have it as part of our radio bezel surround. I'm pretty sure a dial out of any 8 speed truck would work. I had read in that thread Russell was trying to figure out how to keep the column shift and idk if he ever did. If so, that's one less thing for us to have to worry about swapping out. But if not, would make modifying the dash to accept the shift dial much easier if it was just the PRND without the additional buttons.

Appreciate you chiming in. I posted in that thread a week or so ago when I read a large majority but not all and never got a response.

Out of curiosity, why'd you get longer drive shafts? I know in the thread someone said the 8HP is like an inch longer than the RFE and it sat back further so a spacer was needed. But then someone came along and said it wasn't.
The 8HP transmission is 1 and 5/8" longer than the 66RFE so I opted for new driveshafts. I didn't want a spacer in the front.The rear shaft needs to be shorter to ensure the slip yoke doesn't bottom on the transfer case output when the suspension gets compressed
I have long travel suspension and it gets used
 
OP
OP
Odin

Odin

Senior Member
Joined
Oct 31, 2014
Posts
566
Reaction score
373
Location
Arizona aka HELL
Ram Year
2015 2500
Engine
Hemi 6.4L
The 8HP transmission is 1 and 5/8" longer than the 66RFE so I opted for new driveshafts. I didn't want a spacer in the front.The rear shaft needs to be shorter to ensure the slip yoke doesn't bottom on the transfer case output when the suspension gets compressed
I have long travel suspension and it gets used
Awesome!! Thank you for this. This is the information I was hoping to see in that other thread. I just don't think many of the guys doing the swap have the 4x4.
 

gtomike60

Senior Member
Joined
Feb 3, 2023
Posts
187
Reaction score
161
Location
Milford,Mass
Ram Year
2012
Engine
5.7L HEMI
Awesome!! Thank you for this. This is the information I was hoping to see in that other thread. I just don't think many of the guys doing the swap have the 4x4.
Anytime
If you have any more questions.I'll try to answer them
 
OP
OP
Odin

Odin

Senior Member
Joined
Oct 31, 2014
Posts
566
Reaction score
373
Location
Arizona aka HELL
Ram Year
2015 2500
Engine
Hemi 6.4L
Anytime
If you have any more questions.I'll try to answer them
Oh, I'm sure I absolutely will. Haha. This is a project that won't happen anytime soon, but if I can realistically get everything figured out before hand and what addition parts I need specific to my truck that'll help immensely. I saw guys mentioning the cross member that was listed is no longer available. Should I be able to pull one off a 2019 or newer truck and use one with some minor fab? Or have to source the older one from somewhere? Or have to fab an entire new one?
 

gtomike60

Senior Member
Joined
Feb 3, 2023
Posts
187
Reaction score
161
Location
Milford,Mass
Ram Year
2012
Engine
5.7L HEMI
Oh, I'm sure I absolutely will. Haha. This is a project that won't happen anytime soon, but if I can realistically get everything figured out before hand and what addition parts I need specific to my truck that'll help immensely. I saw guys mentioning the cross member that was listed is no longer available. Should I be able to pull one off a 2019 or newer truck and use one with some minor fab? Or have to source the older one from somewhere? Or have to fab an entire new one?
I just had to elongate 2 of 3 slots in the cross member and the mount dropped right in
 

offroadrider12

Junior Member
Joined
Mar 13, 2024
Posts
2
Reaction score
0
Location
MI
Ram Year
2018
Engine
6.4
The same would hold true for a 2018 6.4 2500 tradesman as well correct? Elongate holes in crossmember, 2019+ 8hp75 from a 2500, 8hp75 torque converter & bolts TCM calibration from 19 truck, rotary shifter, cooler lines and etc., driveshafts from 2019 truck or shorten/legthen current ones. Flexplate? Am I missing anything? The 1-2 shift towing kills me with the 66rfe.
 

DILLIGAF

Senior Member
Military
Joined
May 28, 2016
Posts
4,216
Reaction score
7,551
Location
Canada
Ram Year
2012
Engine
5.7
Just modify your original cross member with square tubing, like I did in my thread. its free.

20240105_111844.jpg
 

olyelr

Senior Member
Joined
Nov 18, 2018
Posts
4,674
Reaction score
3,418
Location
Kewadin MI
Ram Year
2016
Engine
6.4
The same would hold true for a 2018 6.4 2500 tradesman as well correct? Elongate holes in crossmember, 2019+ 8hp75 from a 2500, 8hp75 torque converter & bolts TCM calibration from 19 truck, rotary shifter, cooler lines and etc., driveshafts from 2019 truck or shorten/legthen current ones. Flexplate? Am I missing anything? The 1-2 shift towing kills me with the 66rfe.
Yep! The gearing on it is terrible. Maybe its fine with the cummins, i dont know. But it sucks with the hemi. My biggest complaint with my truck is the trans.
 

buckeyexx

Senior Member
Joined
Jan 25, 2015
Posts
677
Reaction score
704
Location
Ohio
Ram Year
2016 Power Wagon
Engine
6.4 Hemi
Yep! The gearing on it is terrible. Maybe it’s fine with the cummins, i dont know. But it sucks with the hemi. My biggest complaint with my truck is the trans.
I agree. Mine is like Jekyll and Hyde. One day it feels great and the next feels terrible. Sometimes it feels very sloppy and can’t figure out what gear it wants to be in. I’ve kind of gotten used to keeping it in 4th so it doesn’t even try to go into overdrive around town or on backroads. It keeps the rpms around 2000-2500 most of the time depending on my speed but it seems happy like that. On more wide open roads of course I let it go into 5th or 6th.
 

offroadrider12

Junior Member
Joined
Mar 13, 2024
Posts
2
Reaction score
0
Location
MI
Ram Year
2018
Engine
6.4
I agree. Mine is like Jekyll and Hyde. One day it feels great and the next feels terrible. Sometimes it feels very sloppy and can’t figure out what gear it wants to be in. I’ve kind of gotten used to keeping it in 4th so it doesn’t even try to go into overdrive around town or on backroads. It keeps the rpms around 2000-2500 most of the time depending on my speed but it seems happy like that. On more wide open roads of course I let it go into 5th or 6th.
Mine is better towing when not in tow haul mode in regards to the 1-2 shift, but I'm afraid I'm going to burn up the trans If I'm not using tow haul mode. Gearing would probably alleviate some of my problems as I have 3.73 gears but I think the 8hp75 would be better? Has anyone done the swap on a newer 2500?
 

62Blazer

Senior Member
Joined
Dec 11, 2019
Posts
1,069
Reaction score
1,258
Location
Midwest
Ram Year
2016
Engine
6.4
All of these comments make me feel old but I'm "just" in my 40s as trucks only had 3 speeds when I was kid, 4 speeds with OD were just coming out when I got my license. Need to go drive trucks made just 10 years ago that still had 4 speed automatic trans if you want to talk about bad gear ratios in comparison to the 6 speed!
 
Top