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Discussion Starter · #1 ·
Hi guys I am looking to swap an overdrive trans into a 1978 ramcharger (its a Jeep scrambler body on ramcharger frame). Current running gear is all 78 ramcharger: 440, 727, np203, d44 with 4.56 gears and 35" tires. I do tow with this occasionally so i do not want a trans that will give me trouble

what i want:
EASY SWAP with OD for fuel economy and comfortable/quiet highway driving. I want to have all parts on hand and complete this swap quickly. I do not want a pain in the ass that takes me a month to get misc parts and problems figured out. I want as bolt in as possible.

1) What transmission to use and what vehicles it came in? Are there any to avoid given the need to occasionally tow?
2) will i need a new transfer case with it or will my 203 work? If so I want to get the engine/transfer case from one vehicle to keep this easy.
3) other than the adapter kit from patc for the 440 to 518 (or other trans you suggest) and the switches for OD from patc, and modifying the crossmember what else do i need?
4) Patc's instructions say that the way governor pressure works is 1lb per mph unless someone has changed tire size or gear ratio- given that both of mine have changed what will this mean for the operation?
5) Driveshafts: will they need to be modified? The instructions for a 2wd 518 swap say the rear gets shortened 3.5"
 

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I can't answer most of your questions, but I am pretty certain the 203 won't work with anything other automatic but the 727.

I don't know what all is involved getting a 440 in front other automatics besides either using a big block case & transferring guts or this adapter you mention. I'm not familiar with it.

Bucky
 

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Discussion Starter · #3 ·
Thanks 712. Doing more research and you are correct. the NP203 will not work without being machined. So now the question becomes what T case do I use? It looks like what i need is a 46RE trans which I believe came in 94-95 dodge 1500 trucks. I am not sure if the correct trans came in any others but those are the lockout version. Would I need to purchase a different torque converter? Still have no clue on how the tire/gear size would effect the governor pressure for the pact shift kit that uses oil pressure sensors. but that note had me worried. I am still open to other trans options but I am zeroing in on the 46re just out of having found a lot more info about that swap online. It is hard to find info on 4wd swaps everything is 2wd... I am wanting to gather parts to do this before the bad weather hits.
 

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Keep in mind that Dodge switched to driver's side drop transfer case in 94, so anything 94-later won't work with your 78 front axle.

Bucky
 

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Discussion Starter · #5 ·
712edf said:
Keep in mind that Dodge switched to driver's side drop transfer case in 94, so anything 94-later won't work with your 78 front axle.

Bucky
Thank you. SO if I get a 94-95 46RH do you know if it will bolt directly up to the 93 np241?
 

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Sam (MadMax), in his thread about his macho build, came up with a method to fit the 203 behind a 518. Basically involved a space that fits between the 518 & 203, then and adapter for the input/output shafts.

The only thing that is a straight bolt up to a 518, with the passenger side drop, is a 241. A 208 will not fit.

For the drive shafts, wait until everything is done, and take the shafts to a driveline shop, and give them the measurements from each U-joint. They can calculate the right length needed.

 

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The NP205 will also bolt up to the 46rh as well.
 

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Yes, my bad.  {hammer}
 

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SuperBurban said:
Sam (MadMax), in his thread about his macho build, came up with a method to fit the 203 behind a 518. Basically involved a space that fits between the 518 & 203, then and adapter for the input/output shafts.
while true...I really wouldn't recommend it unless there was literally no other choice. I had to use two 1" spacers and a 23/23 stub shaft to get proper spline engagement - it 'worked' but I wouldn't do it that way again.

However I will offer another option - I am actually doing a 440/46RH myself, and I'm using a SMR bellhousing adapter kit to do it (there is also the ultrabell conversion but I don't like the thought of using the trans pump bolts to mate the bellhousing). The SMR kit is simply a big precision made adapter ring that bolts up to the back side of a big block, and the small block transmission bolts up to the adapter. It does move the trans back 1/4 inch and as such the flexplate in the kit comes with a machined 1/4" spacer to move the converter back to match. About the only thing I don't like about the kit is it does require cutting off the bottom drivers side mounting ear off the block so the starter will fit, but that's a small price to pay for having a factory overdrive trans properly mated to a factory big block.

Then, any available t-case for a 46RH (and all similar RE models) will bolt right up. I'm doing an Atlas but my plans include serious off-road rock crawling - certainly overkill for any typical 4x4. Personally I'd recommend a 241.

And I wouldn't really recommend a 46RE - the (E)lectronic models require a factory PCM to command the transmission...not awesome (however you can go with a full manual valve body and wire up the OD and LU on toggles and eliminate the need for a factory PCM), but the RH models available in the Dakotas and Rams from about '93-'95 are still hydraulic models and the overdrive and lockup can be wired up with simple toggle switches...at least that's how I'm going to do it. There are other ways to wire up the OD and LU to be fully 'automatic', but personally I'm not a big fan of them.

- Sam
 

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I jave the smr adapter ring and it works pretty good, it jas been on my truck for 2 years.  The nice thing about it is you can go back to a small block engine on the transmission compared to the ultra bell. 
 

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Discussion Starter · #11 ·
Thanks a lot guys!! So I am looking at a 46RH out of a 94 ram 1500 (this should have the lockout and run cooler at highway RPM) and a np241 out of a 92 ram 1500 to get the passenger side drop. Have been having a difficult time locating these parts. I called over 10 junk yards and only 1 of them has the trans. Only 2 have the transfer case. According to everything I have seen they will bolt right up (correct me if i am wrong).

I will need to purchase the big block adapter from SMR to bolt the engine to the trans. A dog ear will need to be cut off the block by the starter.

I need to get the shift kit with the oil pressure sensors from PATC. That will allow my trans to shift into overdrive correctly- does anyone know how the tire size and gear will effect the shift points? I am worried since the note in the install instructions says its 1lb per mph unless you have different gears/tires (i have 4.56 and 35's)

I have a local driveshaft shop that will make me shafts. I am worried about the length of the trans and T-case making the angle of the rear driveshaft too steep with the lift. This drive train is in a CJ8 scrambler so the wheelbase was shortened from  the ramcharger 106" to scrambler 103". Does anyone know how much longer a 46rh/241 combo will be than the 727/203? I found the trans lengthens it by 3.5" but found nothing about the tcase.
 

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Discussion Starter · #12 ·
86w250 said:
I jave the smr adapter ring and it works pretty good, it jas been on my truck for 2 years. The nice thing about it is you can go back to a small block engine on the transmission compared to the ultra bell.
Can you give any advise on the swap? Did you run into any difficulties or have to engineer anything outside of the crossmember?
 

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I'm thinking the 4wd trans, is only 1.5 to 2" longer then the 4wd 727. Not sure where I saw that, to go back and verify. I don't have one assembled right now to go and check. Hopefully someone can confirm, or deny that.
 

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bts0202 said:
Thanks a lot guys!! So I am looking at a 46RH out of a 94 ram 1500 (this should have the lockout and run cooler at highway RPM) and a np241 out of a 92 ram 1500 to get the passenger side drop. Have been having a difficult time locating these parts. I called over 10 junk yards and only 1 of them has the trans. Only 2 have the transfer case. According to everything I have seen they will bolt right up (correct me if i am wrong).
yup they only made the OD/LU hydraulic units for about 2.5 years, which makes them a bit rare, but they're out there with diligent searching. Make sure your trans has the 3-pin connector and not the 8-pin round. Check out the transmission discussion(s) in this thread I started - lots of good info and mostly centered around the Cummins applications but the transmission sections are essentially the same -

https://ramchargercentral.com/diesel-talk/'de-computerize-your-dodge'/

bts0202 said:
I will need to purchase the big block adapter from SMR to bolt the engine to the trans. A dog ear will need to be cut off the block by the starter.
yup that about sums it up. I haven't bolted mine up yet but I mocked the adapter to both the block and trans and both look good

bts0202 said:
I need to get the shift kit with the oil pressure sensors from PATC. That will allow my trans to shift into overdrive correctly- does anyone know how the tire size and gear will effect the shift points? I am worried since the note in the install instructions says its 1lb per mph unless you have different gears/tires (i have 4.56 and 35's)
yeah that's one way, but having done it I much prefer using toggles to 'manually' active both the OD and LU exactly when I want to, but that's my personal preference...

bts0202 said:
I have a local driveshaft shop that will make me shafts. I am worried about the length of the trans and T-case making the angle of the rear driveshaft too steep with the lift. This drive train is in a CJ8 scrambler so the wheelbase was shortened from the ramcharger 106" to scrambler 103". Does anyone know how much longer a 46rh/241 combo will be than the 727/203? I found the trans lengthens it by 3.5" but found nothing about the tcase.
you'll very likely need a Ford 1350 DC (double cardan) output flange coming off the t-case rear output (similar to the front but bigger and beefier) - machined down to fit the 241 output seal, and cut the leaf spring perches and rotate the rear pinion up to be just shy of zero angle into the driveshaft, and re-weld the perches = best way to get zero vibes...
 

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Not to hi-jack this thread, but did Dodge offer OD on a pre-94 4x4 with automatic transmission? If so was in gas trucks (LA) only or did the Cummins trucks offer them too?

Also what year did the Cummins powered trucks switch away from the NP205?

Thanks,

Bucky
 

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First of all, the difference in length between the 4x4 727 and the 4x4 46rh is 5.5 inches. I had both transmissions side by side on the floor of my garage when I measured them. The transmission mount to cross member was identical distance from the mounting flange to the cross member mount.
However, both transmissions were for the Cummins adapter bolt pattern, if that makes a difference.

712, yes, the 46rh was offered on pre 94 4x4. I'm just not sure when. I thought 88 or 89. The Cummins trucks went to the 46rh in 91.5 until the 94 body change. Then, the 47rh with OD and LU converter were installed in the 94 and 95 models. For 96 model year, the 47re was used in the Cummins trucks.
As for the NP205, 93 was the last year in the Cummins trucks.
 

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Discussion Starter · #19 ·
All great info. I guess I will have to just measure the trans/t-case combo when I have it in front of me and hope its not too much longer. Swapping the np241 just brought a whole new issue into my head. The 203 is full time 4wd. Since I have to put in the 241 for the 46rh to work, would I be able to use the 2wd? I dont have manual locking hubs. If I just left it in 4wd I am sure i will be okay but it would be nice to have the option on road trips.
 

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1990 was the first year for the A518/46RH, used only with gas engines at the time.
 
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