46rh is missing. Goes between 727 and 47rh in your list. Furthermore, it would probably help if we knew what vehicle you intend to do a Cummins conversion in.

The CTD transmission bolt pattern to the adapter plate is different from the gasser tranny bolt patterns. The exception is the Dodge 94 and later transmissions for the V10. They share the same bolt pattern as the CTD starting with the 47rh auto or nv4500 manual bell housing. Just make sure that if you buy a 1st gen adapter plate, you must use the 1st gen starter. 2nd gen the same.

In my case, I wanted an automatic and overdrive and did not want RE or electronic. My two choices were the 46rh or 47rh. So, I went with the 46rh because I found it first and in need of a rebuild. The 47rh adds a lockup converter if you want that.

 

Thanks for that. I updated my original post.

 

Presuming you're going to use an early 12v 1st gen 6BT, and presuming you want an automatic, I'd recommend either a 518 or a 618 (46RH or 47RH) diesel 4x4 tranny. Either a 205 or a 241 t-case bolt right up. You cannot use a gasser tranny behind a diesel. You will only really need a good aftermarket converter if you plan to tow heavy.

 

presuming you're going to use an early 12v 1st gen 6BT, and presuming you want an automatic, I'd recommend either a 518 or a 618 (46RH or 47RH) diesel 4x4 tranny. Either a 205 or a 241 t-case bolt right up. You cannot use a gasser tranny behind a diesel. You will only really need a good aftermarket converter if you plan to tow heavy.

What he said.

 

Thanks a lot for the info. I am still shopping for a motor and I think I have looked at everyone for sale between Sacramento, San Diego and Phoenix LOL so-

I have found an 89 Cummins with a 727TF trans. Is this trans usable? I don't know anything about it but the motor starts right up and runs seemingly good.

And is it Cummins or Cummings? Spell checker says the latter, most others say the former. LOL

 

no 'g' - just Cummins .

The 727 is a very stout tranny - same as the gasser version.  The non-intercooled auto trucks (89-91) all had 727s - no overdrive.  About as bulletproof as it gets.  But it also required 3.07 axles to make up for the overdrive.  IIRC the 5-speed trucks had 3.54s.

I had a 90 Ramcharger, with a non-IC Cummins, a 727, and 3.07s.  It was my daily driver, and it was a fantastic running truck.

 

So 410 or worse yet 486 gears would be out of the question with the 727 trans. Correct?

How would the transfer case work with the 727? Divorced or replace the tail shaft housing?

What about a stock 1976 4 speed manual and a np203? Thats what I already have on the parts truck.

 

The 727 with 4.10 gearing would work as long as you stayed off the interstate highways. Your maximum speed would be like 55 MPH at high RPMs. I already went thru that config. That's why I went with the 46rh with overdrive.

Also, keep in mind that the 89 thru 91 with auto trans also had the D61 front axle and D71 rear axle. Both are heavy duty axles, but, came with 307/308 gearing to make up for the lack of overdrive.

91.5 thru 93 with the 46rh auto trans with overdrive had the D60 front axle and D70 rear axle.
However, the 89 thru 93 with manual getrag 5 speed all had both the D60 front axle and the D70 rear axle.

Hope that wasn't too confusing. Dodge created that, not me. The point is... you should be looking for a donor rig with the D60/D70 combo...

 

Thanks for all that.

Is there a difference in heavy duty-ness between the 3/4 ton and 1 ton axles? ( 4x4 dodge donor truck)

 

Nope - well other than the hubs for the duallys, and the dually's are about 2 inches wider (generally). Other than they they're basically the same. And, you can put the 1/2" (3/4-ton SRW) studs in the dually hubs and thus convert the dually hub to accept a SRW wheel

 

I would like to go the other way and keep the dually wheels.

If I come up with a 3/4 ton donor, I can change the hubs and live with a rear end thats 2"narrower. Is this doable? Crazy? Too expensive?

 

Unfortunately, I'm 99% certain the hubs are not interchangeable You need the wider axle so the inner dually wheel, when flipped in, won't rub the leaf spring.

 

unfortunately, I'm 99% certain the hubs are not interchangable You need the wider axle so the inner dually wheel, when flipped in, won't rub the leaf spring.

Just to add to what he said there is also a width difference in rear dually axles between a cab & chassis truck and a regular pickup dually. The C&C being appx 6" closer on the wheel mounting space (the inside dual will rub horribly and the outside will sit in the middle of the big dually fenders). A standard dually PU bed will not fit on a truck that was originally a C&C truck without wheel spacers or swapping rear axles. I have not confirmed but I believe the wms of a C&C is very close to that of a regular 3/4 ton or SRW 1 ton rear axle.

 

Thanks for the info on the axles. I would like to confirm the difference (in inches) between a SRW axle and a Cab and Chassis DRW, if anyone knows for sure. I have the cab and chassis and would like to have the option of using a SRW axle, when I find it.

I have an update which will tie back into my original transmission question.

I now have 2 Cummins engines. LOL Not 1, but 2! Yeah, I know, thats what my friends say, but they know me. LOL I am stoked!

The first one is a 91 and may be stuck, the second one is a bit newer (seller wasnt sure and I have not checked or had a good look at it yet) but he knows its a 94-98.

The 2nd motor is still in the truck burried in the back of his shop and it will take a good day of work to dig it out.

So, transmissions.

J10mike posted this earlier-
"The CTD transmission bolt pattern to the adapter plate is different from the gasser tranny bolt patterns. The exception is the Dodge 94 and later transmissions for the V10. They share the same bolt pattern as the CTD starting with the 47rh auto or nv4500 manual bell housing. Just make sure that if you buy a 1st gen adapter plate, you must use the 1st gen starter. 2nd gen the same."

OK, so there is an adapter plate, and a trans. How many options exist in adapter plates? Is this a stock Dodge/cummins thing or are they sold aftermarket? (both?)

Equally important is the transfer case. Which transmissions will except the transfer case? Transfer case options?

I have read a lot about this but have not yet found a tech article that ties it all up for me yet. If you know of one, please link it. I am in a steep learning curve right now and all these questions will end ...... one day soon, I think. LOL
Thanks for all the help!

 

Believe me, the questions don't end. Just when I think I've got it all, I find I have more questions. Don't worry about the questions.

Yes, the first gen 89 thru 93 uses different transmission adapter plates as well as starters than the second gens. So, make sure you take that starter with the engine if it already hasn't been pulled. As for flexplates, I had both first and second gen flexplates side by side. I didn't see a difference between them with the naked eye. But, I didn't count the teeth either. Anyway, since I had the first gen adapter plate and starter, I used the first gen flexplate.

As for transfer cases, all 80 and later Dodge transfer cases use the standard NP bolt pattern. You can use a 205, 208, or 241. The 89 thru 93 used the 205. 94 thru ? used the 241dhd. Although, I believe the 205 from behind the getrag 5 speed use the 29 spline shaft.

 

If you can't do an overdrive trans, auto or manual, don't even waste your time. It's pretty much pointless, diesel NEEDS overdrive for any kind of usability. Let's see, Dodge only went with non-OD for a year and a half? There's a reason for that. To have any semblance of highway usage, it has very high axle ratio... which in turn limits low-end pulling power.

I can already hear it, "but diesels have so much low-end torque," yadda yadda. You still can't overcome certain mechanical forces, 400ft-lb and a 2.45 1st gear coupled with 3.73 or 4.10 gears will ALWAYS pull better than the same but with 3.07 gears. Always. Not just from a stop either.

I'm also a fan of lockup converters, slippage in the converter creates heat. Heat is bad. Your trans dies. End of story.

So, you're limited to, in my opinion, the 47RH/RE or 48 RE. The RE versions will cost about 2500-3000 just for the standalone TCM and accompanying valve body, but you have 100% control over every function of the trans. The RH version is fully mechanical, you'll need a switch for converter lockup and another for OD.

As far as a manual, skip the Getrag; NV4500, NV5600, G56. Done.

 

Ok, good information and just in time. I am looking at an auto thats not an overdrive and you just confirmed my suspicion.

Scatpack you said "The RH version is fully mechanical, you'll need a switch for converter lockup and another for OD.

As far as a manual, skip the Getrag; NV4500, NV5600, G56"

All of these can be used behind a 1st or 2nd Generation engine?

I am definitely a "fully mechanical" kind of guy. 47Rh then is the one I am looking for in an auto.

thanks much, very helpful.

 

the only real difference between the 2nd gen 47rh (A61 and the 1st gen 46rh (A51 is the 618 has a lockup converter, hence the thicker engine adaptor housing. The 618 is a bit difficult to find, and the 518 is easier. Unless you 'need' a lockup converter there would be nothing wrong with using a 518. LOTS of folks think all 518's are the same, but the fact is most for sale on craisglist etc just advertise a 518 for a 93 Dodge Ram...but it's usually for a gasser. Every diesel converter has a 6-bolt flexplate and converter. The gassers are 4-bolt.

 

More good stuff, thanks Mad Max

So the gasser and diesel 518 is the same trans but the flex plate and torque converter are diesel specific? Did I understand that correctly?

 

no, the gasser and diesel tranny's are 'similar', but the diesel version has a different bellhousing (that requires the engine adaptor), uses a 6-bolt converter, and has stronger guts/more clutches.  They essentially operate the same, but the two are not interchangable.

 

Alright! the mud is slowly getting clearer, thanks again.

another question-
On the manual transmission side, If I should come up with a Getrag, rebuilt with 8k miles on it for a good price and I decide to use it, will it swap our with the nv4500 or 5600 easily, like bolt in?

I do have a line on that transmission and it comes with some axles I am considering.

 

Thanks for the info on the axles. I would like to confirm the difference (in inches) between a SRW axle and a Cab and Chassis DRW, if anyone knows for sure. I have the cab and chassis and would like to have the option of using a SRW axle, when I find it.

The cab and chassis rear is 2" wider than a standard SRW axle. It has a WMS dimension of 66 1/2".

 

Scatpack you said "The RH version is fully mechanical, you'll need a switch for converter lockup and another for OD.

As far as a manual, skip the Getrag; NV4500, NV5600, G56"

All of these can be used behind a 1st or 2nd Generation engine?

Absolutely. It's been a while since I've looked into it, but I believe for the 47RH you need the second gen adaptor plate and starter. I used to have a great link with pictures of a 47RH swap into a 1st gen (89-93) truck. I'll see if I can dig it up again and link it for you.

Same with the manual trans, just need to correct adaptor plate. Again, I've read some good write ups on swaps, I'll try to link them as well (they were all saved on my old Windows laptop that took a dump.)

 

some specific links would be great. I find a bunch of stuff but sorting through it all burns me out and then never know if its good info or not. I have seen many contradictions in advice.

Thanks

 

There were several transmission options left out of the conversation. Think of this, the Cummins is also used in the medium duty truck market, and that market allows customers to spec their trucks with a variety of engine and transmission options. This means you can take advantage of those options and get away from common difficulties of using Cummins specific Dodge transmissions. For automatics, Allison is the leading manufacturer of autos in the medium duty market. Not all of their transmissions are computer controlled and many of them can be found relatively inexpensively. There are more manual transmission options too. Eaton-Fuller, Clark, Road Ranger, etc are strong transmissions found behind the 5.9

The significant disadvantage of these transmissions is that none of them were designed to use a married transfer case, but you can use a divorced t-case

Ed