Getrag/NV4500/NV5600/NP205 questions...

[SRath]

Hi guys! Hope you don't mind a second generation guy jumping the fence to ask you some questions about the Getrag and NP205 trucks.



I'm converting my '96 from a NV4500 to NV5600. While I'm doing that, and having the driveshafts altered anyway, I'm also trying to install an NP205 to replace my NP241DLD.



I just aquired a Ford NP205 with the 31 spline female input. The NV4500 and 5600 have 29 spline output shafts, so I was looking at buying Advance Adapter's kit to mate the two. It is just an aluminum adapter plate and a spud shaft with 29 spline input to 31 spline output. The aluminum adapter is only a couple inches thick from the looks of it in their photo.



What I don't like at all about their kit is the designed need to cut 0. 600" off my transmission output shaft. I cannot for the life of me understand why they did not just make the aluminum adapter plate 0. 600" thicker. . ?! The thought of permanently altering the output shaft of that NV5600 makes me cringe. Replacement parts are very tough to get.



The kit is actually intended to enable using an NV4500 in a Ford truck with an NP205; but you can see where it would work the other way, too. Fellow TDR member tlgdiesel turned me on to this neat little adapter kit (thanks!). It is expensive at over $400, though.



However, as I was reading some of the many websites with Ford and Dodge and Chevy NP205 info (mine have always been Chevy versions and I have several still), I found some information stating that the early Cummins Dodge's with the getrag and NP205 had a rare 29 spline input in the t-case. No other model does. This could be interchanged with the Ford 31 spline input since all the inputs with the large bearing will supposedly interchange on NP205's.



Furthermore, both the Ford NP205 and my NV5600 (4500 too) have a round bolt pattern. I have not compared the actual bolt pattern size and spacing yet to see if they would mate or not. Wouldn't it be great if they did?



What I would like to know is:



1) Has anyone here converted their 1st gen Getrag Dodge to an NV4500 or 5600? If so, how did you do it?



2) Is the getrag output shaft the same 29 spline and the same diameter as the NV4500/5600?



3) How far does the output shaft on a Getrag stick out beyond the mating surface?



4) Does anyone know where I can find a Dodge NP205 with that 29 spline input or at least the input shaft itself?



My hopes are that maybe by swapping in the Dodge 29 spline NP205 input shaft, I may avoid cutting my transmission output shaft as well as eliminate the need for the spud shaft from AA. Who knows? Maybe I could be lucky as a lottery winner and the bolt pattern and size of the NV5600 and Ford NP205 wilol match up, too! (dream on?).



I sure appreciate any info!



Thanks! Scott

 

[AKimmel]

Quad4x4.com sells the 29 spline input shaft you want. I would check with a Dodge dealer and get a price on one if they are still available. Quad4x4 sells good stuff, but they are high on everything. A NP205 from a Getrag truck will bolt up directly to a NV4500 and I'm pretty positive to a NV5600 without any adapters other than the factory one thats on there already. There have been plenty of posts on here of guys coverting their Getrag to a NV4500 and I remeber one that went to a NV5600. So you may try searching for those old posts. As far as the Ford round pattern matching the NV5600 pattern, you'll just have to try that yourself. Also all 5 speed 4x4 Cummins trucks from 89-93 have the 29 spline NP205, if you have to buy a used one.

 

[SRath]

"A NP205 from a Getrag truck will bolt up directly to a NV4500 and I'm pretty positive to a NV5600 without any adapters other than the factory one thats on there already. "



That Dodge getrag/np205 factory adapter would seem to be the part I need to find first, since I'm using the Ford t-case and don't have one.



My NV5600 is stored in an awkward to reach position right now, but a quick check of the bolt hole pattern and spacing seems to indicate it has the same bolt pattern as the Ford t-case. I found another bit of internet info that says the Ford holes are even clocked the same as Dodge, whereas the later model Chevy round pattern, though also the same size, is clocked differently.



So finding the Dodge factory t-case adapter (more of a spacer, isn't it?) and installing a Dodge input gear shaft in the Ford NP205 ought to work. Without having to cut my transmission's output shaft shorter.



I thought at first the Dodge 29-spline input for the NP205 would be an internally-splined one like the heavy duty Chevy 32 spline and Ford 31 spline are. But from the photo on Quad 4x4, it looks to be an external spline shaft that requires a coupling sleeve between it and the transmission. Can anyone confirm that from their own experience with an '89 to '93 cummins/getrag/dodge?



That would explain why a spacer/adapter is needed even though the t-case and transmission share the same bolt pattern without an adapter.



I did not see a factory or factory-style adapter offered on Quad 4x4, or anywhere else yet, for the Dodge Getrag/NP205. Does anyone have any possible sources for one?



Thanks AKimmel !

Scott

 

[AKimmel]

On a Dodge 205, the adapter from the t-case adapts the figure 8 pattern to the round pattern on the back of the transmission. The adapters are all the same on auto's, 5 speeds, and even gas trucks. The only difference that you may run into, is the 5speed (29 spline), uses a bigger bearing than the auto (23 spline) on diesel and gas trucks. If you had a 23 spline adapter, you should be able to just have the bearing bore enlarged at a machine shop. I've never done this myself, just read alot on here. I do have 3 trucks with 205's, so I can measure the lengths of the adapters when I get a chance and post it. Two are gas 1 tons and the other is my diesel truck in my signature. Oh, they do use a coupler between the output of the trans and the input of the t-case.

 

[MMiller]

https://www.turbodieselregister.com...90516-nv5600-my-first-gen-just-completed.html I have read this numerous times, and may someday put a nv5600 in my first gen, just for better towing, maybe even a G56. But for now my getrag seems to be holding well again.



I fail to see why a 30 year old 205 would be an upgrade over your current t-case, or a HD unit. Why are you wanting to do this?



Michael

 

[AKimmel]

I measured the adapters on my diesel and gas trucks and they both are right at 4" in length from the face of the t-case, to the round bolt pattern where it bolts to the transmission. I wondered the same thing as MMiller, why do you want to get rid of the 241. They are one of the strongest aluminum t-cases and they have a way better low range, 2. 73 vs. 1. 96 in the NP. 205. Plus they are a heck of a lot lighter. I'm not downing the 205, but I don't know that I would get rid of the 241 for a 205.

 

[SRath]

AKimmel; the info I am finding says the Dodge NP205's bolt patterns are like the Chevy's: Figure 8 for most years, but then they went to the circular 6-bolt pattern in the final years of the first generation Dodge diesels. The '93 Cummins diesel was the last pickup ever built to receive the NP205 :{. Your info on the spline and bearing differences between the manual transmission and automatic trucks jives with what I have been reading. Chevy also had the same differences, depending upon what transmission the t-case bolted to.



All the married Ford NP205's had the same round pattern and same 31-spline input regardless of year or transmission (that kind of intelligent interchangability was pretty rare for Ford and ahead of Chevy and dodge). Not to mention the Ford 205's had the top-notch 32-spline outputs front and rear!



As for the "why change to an NP205", I'm just oldschool, Michael. I like aluminum cases and drive chains on my dirtbike, not my truck. I will never be convinced that any aluminum-cased, chain-driven t-case can stand the test of time as reliably as the most famous and widely used t-case of all time, which, hands down, is the cast iron, gear-driven, ingeniously well-designed, NP205.



Every 4x4 I have ever owned either came with, or was converted by me to a NP205 except for a rustbucket CJ-7 jeep I left stock and only owned for a year or two. I have never had an NP205 let me down under any circumstance.



It is often said among the truly hard-core off-roaders and pullers that you will break something in virtually any pickup's transmission or axle long before you break something in a well-maintained NP205, and they require extremely little maintenence other than clean oil. An absolute truth? Of course not. But no similar claim has ever been made for any other t-case.



Truth be told, I like my 2nd generation Cummins Dodge very much. The '96 12-valve engine I have was just about the pinnacle for the motor, too, imho. The styling and interior is very nice. I love the extended cab which has the more comfortable forward-facing rear seat which the 1st gen did not, as far as I know. It's rust-resistance (so far) is better than any pickup I have ever owned, too.



But I like the way the '93 and earlier Cummins Dodge's chassis was built much better. They are practically the sister trucks of my beloved early Chevy's (oops ), and the important parts even interchange fairly easily between the Chevy and Dodge. That's nice because the Chevy always had superior axle shafts and hubs on their D-60's compared to the Dodge. There ONLY shortcoming with the 1st generation Cummins Dodge as far as I'm concerned was that the NV4500 and NV5600 were not built back then. But that is an incredibly easy conversion, I understand.



I really, really miss the leaf spring front suspension and "real" Dana 60 front axles of the old trucks. And I miss the peace of mind that a NP205 gives me. Why have the ultimate pickup engine (12-valve cummins), the king-kong of transmissions (NV5600), great axles (in name anyway, in the case of my 2nd gen) (dana 60/Dana80), and be content with not only a so-so t-case (NP241) and even the light-duty version of it?



Unless I figure a way to convert to a leafspring front and a "real" Dana 60, I will always come up just short of my personal "dream truck", but it will be very close. Finding a rust-free, cherry '93 manual transmission, x-cab Cummins Dodge would be nice, but you guys all know how hard and expensive that is.



As long as I am paying to have the driveshafts lengths changed for the NV5600, I want to upgrade my t-case. I have considered my options for upgrading from my 241DLD carefully, including switching to a NP271. Finding a '94 through '97 NP241DHD is very tough and they are incredibly expensive even used. I need the speedo sender in the t-case which the later NP241's don't have. For the same or even less money, I can have my favorite t-case, and it is a piece of cake to convert the mechanical cable speedo to an electronic signal for my speedo.

 

[AKimmel]

The later NP205's in Dodges still use the figure 8 pattern just like all the ones before it. I have one of the last year uses in my 93 drivetrain I used in my diesel conversion. I wish I had some pictures from when mine was apart, but you may find some on here or even ebay. A 205 from a Dodge has the figure 8 pattern drilled in the case itself and is converted to the round pattern through the 4" adapter I was talking about before.

 

[SRath]

Here is one of the better online info sources I was talking about, AKimmel. High Impact - NP205 Tcase Data Sheet



"Dodge NP205 Transfer Case

The Dodge NP205 transfer cases are mostly an 8 bolt pattern like the early Chevy. Some late units had the 6 bolt circular pattern. These units all have a right hand drop. Most are supplied with a 23 spline male input shaft and used with a coupler.



29 Spline Dodge: There is a fairly rare 29 spline NP205 used in Dodge trucks behind the Getrag 5 speed. The NP205 used behind automatics are all 23 spline, even in the 1 Ton Cummins apps.



Later applications of this case appear to use a short adapter to bolt to the front of the Tcase, and has the 6 bolt circular pattern found on the transmission tailhousing adapter. This adapter also functions as a bearing retainer in the front of the Tcase and carries the input seal.



The casting used for the 23 spline input is different than the one used for the 29 spline, due to the larger bearing and seal. The 23 spline part CAN be machined out to accept the 29 spline parts, but with TLC as it does not leave much meat in some places.



These adapters seem to be kinda hard to find on the boneyard circuit, and are apparently no longer available new from Dodge.

Also see data on swapping input gears lower on this page. "



It does say "it appears", though, so you can only go by what you know. And I would not be the least bit surprised if Dodge used up all of their remaining old-style figure-8 t-cases and adapters, too. Is it possible someone before you may have switched t-cases to the older style?



I know if I ever sell my K30, I will definitely swap the rare new-style round NP205 t-case and TH400 adapter for one of the old figure 8 style I have. The new ones are very rare and worth quite a bit more money.



Here's another good site with links to even more good info: NP205 New Process Transfer Case Diagrams and Information



I guess the interesting question based upon what you have on your '93 is:



Does anyone else here have a Getrag/NP205 combo in their '87 to '93 Dodge Cummins and what type/shape of adapter does it have? That round one is either very rare or does not exist and it would be nice to find out which is the case.



Thanks again, AKimmel.

Scott

 

[MMiller]

I'll try and look at my 205/getrag combo, I think it has 6-3/8" nuts, and they are in the figure 8 pattern. I'll look for sure though.



Try lomax.com, and get one of their complete 205s with thicker gears, and more desirable 3:1 low gear reduction.



Michael