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8 spd swap

35K views 89 replies 17 participants last post by  TRusselo 
#1 ·
I took a look around the forum and didn’t see anything in the titles, if it’s been covered in another swap thread my apologies but this probably deserves its own thread.
Anyone done this yet? With controllers coming out I’m guessing it’s a matter of time (Sound German Automotive has one). My question is how much of a direct swap is it nuts and bolt wise for a 4wd? I’m guessing it would be pretty straight forward as the 4th gens used the 65rfe and then switched to 8hp70 and I don’t imagine them moving t cases around and altering driveshaft lengths so I’m guessing the 4wd 65RFE and the 4wd 8 speed would be the same length wise, I’m also pretty sure they kept the same t case when they switched over as well so they should be the same on the tail end. As the 65 and 545 are virtually the same, I’m guessing it would pretty much be a bolt in affair for older trucks? They switched from the NP/NV t case to a Borg Warner at some point in 4th Gen rams, but I think they bolt to the tranny the same, so I think the NP/NV t case in my 2005 should bolt to a 8hp70. This is all speculation so I’m wondering if anyone has an 8hp70 to measure up so I can compare it to a 545 I have in my garage (overall length and the t case adapter bolt pattern)
 
#36 ·
the 8sp swap I was involved with we used a floor counsel and shifter out of a 2015 Charger., a SGE TCM and harness.
 
#38 ·
I have no problems losing the center seat and building a console as long as it doesn't end up looking tacky.
 
#40 ·
Remember tacky is in the eye of the beholder
 

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#45 ·
Nannyberg gets elected you won't be allowed to buy that BIG GULP ...LOL
 
#48 ·
I have an update on this. I have been in numerous conversations with Sound German Automotive and have decided this swap is going to happen. I have a console from a 2019 test fitted with a shifter from a Charger. I will be trying my hand at customizing some trim for better fitment and see how it goes. Also the transmission is on it's way, it was extremely hard to find a two wheel drive truck transmission north of the border so I have one coming out of Portland and should arrive in a week or two. So far so good.
 
#57 ·
as long as your truck has a hemi then yes you can do the swap.
 
#59 ·
Imteresting, I dropped from 4:10 to 3:92 with tall 31" tires. It gives a good highway rpm/gear using a 46re trans. What converter stall do you use?
 
#60 ·
it is just the stock challenger converter, i believe they're around 2200-2300 but don't quote me on it. i saw the number somewhere online once but I don't remember what it was. low 2000s anyways. I do wonder if a high stall converter would make enough of a difference to justify the expense, seeing as though aside from launch it stays locked basically all the time.
 
#61 ·
Most folks go to higher stall converter to get heavily cammed engine high enough to pull the gear they are using. I start in 2nd without issue.. (3500 9").. actually I can just as easily start in 3rd.
 
#62 ·
yes i realize that, i am saying though that aside from the launch it is always locked so there are really no flash stall benefits or anything, and with a 4.71 first gear you'd need a cam in the 300+ degree range for there to be any delay in getting up on it lol
 
#63 ·
All true... what rpm are you trapping at? That would be a good reference.. with your truck I would gear for 6500 @ 130mph.. as a start.
 
#64 ·
couldn't tell you, i haven't been to the track this summer at all. but for now I am leaving the powertrain setup pretty much where it is, aside from a better driveshaft which I will get built this winter. with those 4.56's in there, that driveshaft is spinning like a friggin dremel. with the tire on the truck, 305/35/24, it is turning roughly 2,838rpm at 60mph. it is 3.5"/0.83" and 62" from the output flange to pinion flange, minus about 14" for the yokes and slip joint. it is just too risky going much into triple digit speeds, which was a big reason for staying away from the track and just winding it out period. I love the 4.56's for driving around so I don't want to do a gear change.

but i am done tossing money at this drivetrain, I decided a this year that I am going to start building a big block for it instead, but that will be a multi-year project as the cost of it makes me want to barf. so now any mods (aside from the driveshaft) will be geared towards that.

this winter I am doing a full suspension change, tubular control arms up front and a 4 link out back, with Ridetech adjustable coilovers all around. aside from the obvious benefits of that setup, it will take a decent amount of weight out if the truck too. 4 coilovers, 5 bars, and the tubular lower CA's probably weigh the same as 1 leaf spring. so with the leafs, torsions, those giant cast lowers, torsion crossmember/keys all gone, that should be a pretty good chunk of weight out of there.
 
#65 ·
I can recommend truckarm suspension. Rides good, track great at speed and handles big power without issue. Kits available from Hot Rod to Hell. I use coilovers in the front but only replaced the coil spring and shock. I still want to redo the whole front suspension with something lighter.
 
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#67 ·
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#66 ·
I probably will not have any more updates on this until next spring. I have bought the transmission, a center console for the console shifter as well as a shifter. I have various other parts accumulated such as cooler lines and stuff as well as I did just get the torque converter back from TCS which is now a built high stall.
I just paid a big dentist bill for my oldest son today so I am tapped for the season. This is literally the only benefit of living up here in that it sits parked for six months of winter while I save money for the next modification. I will probably order the stuff I need from Sound German during the course of winter.
 
#82 ·
I probably will not have any more updates on this until next spring. I have bought the transmission, a center console for the console shifter as well as a shifter. I have various other parts accumulated such as cooler lines and stuff as well as I did just get the torque converter back from TCS which is now a built high stall.
I just paid a big dentist bill for my oldest son today so I am tapped for the season. This is literally the only benefit of living up here in that it sits parked for six months of winter while I save money for the next modification. I will probably order the stuff I need from Sound German during the course of winter.
Sound German is the way to go, he's spent a allot of time thinking out and working out his kits.
 
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#71 ·
Still using the oem sway bar. Red weighs 4600lbs so is no light weight but has a phenomenal launch on slicks. The supercharger and it's supporting equipment is the only weight thats been added. Alot has been removed and there is still another couple hundred pounds that could be removed considering tailgate and tonneau cover. Keeping in mind red is a street truck and not a dedicated racer I am very happy with it..
 
#72 ·
so what is your opinion on the coilovers, and do you have double adjustables all around or just up front?
 
#73 ·
What's not to.like about coilovers? They are light, ride good, adjustable for height. As for adjusting them there are something around 250 combinations. I got tired of changing settings and finally left them alone with roughly a 40/60 in front and 50/50 rear.
 
#74 ·
what spring rate did you go with?
 
#75 ·
I'll need to look at my notes, but I think they are 450# rears and 550# fronts. The fronts are ViKings and I had to select the shocks, springs from their catalog to build a kit. Actually I used Vikings because they had a very descriptive catalog.
 
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#77 ·
4wd will be easier because of the transfer case output vs the 2wd trans tailshaft. the 2wd is a flanged output so you will need a slip joint in the driveshaft with a 2wd transmission, with a transfer case you have a slip yoke, so a simpler and usually stronger driveshaft, depending on design of course.

I used a transmission from a Challenger and it has a flanged output as well. the car driveshaft has a CV/Giubo joint on the driveshaft because since it has an IRS setup, there is no change in the distance between the trans and diff during suspension travel, so a bit of lateral/twisting movement is all that has to be accounted for. I used a Sonnax slip yoke eliminator flange which bolts onto the trans output flange and lets you run a 1350 u-joint, and I have a splined slip joint at the front of the driveshaft, which gives the movement I need but is stronger than a slip shaft.
 
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#78 ·
4wd will be easier because of the transfer case output vs the 2wd trans tailshaft. the 2wd is a flanged output so you will need a slip joint in the driveshaft with a 2wd transmission, with a transfer case you have a slip yoke, so a simpler and usually stronger driveshaft, depending on design of course.

I used a transmission from a Challenger and it has a flanged output as well. the car driveshaft has a CV/Giubo joint on the driveshaft because since it has an IRS setup, there is no change in the distance between the trans and diff during suspension travel, so a bit of lateral/twisting movement is all that has to be accounted for. I used a Sonnax slip yoke eliminator flange which bolts onto the trans output flange and lets you run a 1350 u-joint, and I have a splined slip joint at the front of the driveshaft, which gives the movement I need but is stronger than a slip shaft.
Awesome info. Can you point me to a thread where there is more info on the swap, or could you perhaps share your experience here? What was all involved? Custom mounts? Custom shafts? where did you get stuff? Where were the challenges? Did you use the German Automotive harness that was talked about on the first page?
 
#80 ·
there is always more to learn, and I have made a couple tweaks. running the standalone on the engine was something I definitely wish I had done from the start too. I will do a detailed writeup with some pictures in a few days, I'm not at home right now. I do like the performance/driveability, but I am on the fence about whether I would still do it if I could do it all over again. I will explain it in more detail in a couple days.
 
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#83 ·
Been involved in a few 3rd Gen (2nd& 4th gen and a pair of 77s) 8 speed swaps, lots of upsides , major down side is cost... I can not emphasize the importance Sound German and his PCS system........

I'm helping a new coworker swap a NAG1 and transfer case from a 06 JeepSRT in to his 05 Ram Daytona with Sound German's NAG1 PCS.
 
#86 ·
Well change in plans , he's going with HTG tuning controller instead of Soundgerman Never used it with a NAG1 , used it twice with the 8sp ....I'll keep you all posted.
 
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