Transfer case extension housing fun!!!

[Haggar]

Guys,I thought I would post this up since I had trouble finding the information anywhere online in one place.Our transfer case models are either NP 241 DLD or NP 241 DHD. There seems to be no rhyme or reason to whom got which, though I suspect that more DHD's were installed in the 3500 series. My TC is the 241 DLD. This has the "2 part" or "2 piece" tail shaft extension. (the DHD had a 1 piece extension)BE careful. I have found sites that say the 241 DHD uses the same extension housing, but that is totally impossible. Don't buy into it. also a guy on ebay has an extension at a good price, but each time you click his links, it takes you to 2500 and 3500 diesel quad cabs that apparently got NP231 TC according to dodge part numbering.... the Dodge pn book is a bit misleading too.... apparently our tc is called a "shift on the fly"... but either way it says the 231 got installed.... I have yet to see a 231 behind the cummins or V-10, but it maybe could have been an option...I have found that many of the other NP 241s (especially the NP 241C that is a gm part) use the same extension housing, only differing in output seal. (the dodges use the extended boot, GM does not, I will probably use the Dodge part in my GM ones from now on!!!) There are two casting numbers that work on our (may be more, but these are the only ones that I have found.) C-16258 and C-17460. I had places tell me these were interchangeable and had places that said they absolutely were not. They are interchangeable to the best that I can measure. The 17460 is a modification of the 16258. I could be wrong, but the number is later and I consider it better. The only difference I can measure, is the output support bushing on the 17460 is not as close to the seal as found on the 16258. The 16258 is a PITA to remove the seal, as the seal tool does not have enough room to hook between the bushing the seal so you cannot hook the seal. The 17460 moved the bushing slightly toward the front of the vehicle. This does two things, there is more room for the oil between the seal and the bushing, and ease of replacement.One thing I have noticed, the 241 does not have as many drain back holes as the 231 (the 231 has what looks like 4 the 241 has only one). I lost the orientation of the drain back hole under the pilot bushing. I assume that the tail shaft extension fills with some fluid and the helix in the bushing will cause a pressure differential. edit: I found that the orientation is fixed. The 4 bolt pattern is not a square pattern. The tail shaft extension will fit properly in only one orientation.Check your bushing!!!!! I thought mine was "fine". Compared to the new one, it is 0.015" larger..... That may have been where that slight drive-line vibration was!!! should know this weekend.Hopefully I will no longer be a rolling superfund site!!!Will try to post a few pictures up.GL HTH Hag

[GSP7]

I have a 241 DLD

I have found that many of the other NP 241s (especially the NP 241C that is a gm part) use the same extension housing, only differing in output seal. (the dodges use the extended boot, GM does not, I will probably use the Dodge part in my GM ones from now on!!!)

Good to know. I have a 81 chevy k20 . I was just looking at my rear TC seal.

[98whitelightnin]

I thought all the 5&6 speed trucks came with the DHD version and auto trucks came with the DLD version. Today a member on CF said his auto dually had the DHD and he wanted to swap to a 5 speed and wondered if his Tcase would bolt up to the nv4500. Another member said they input shafts are different from 5 speed to automatic trucks even if they both have DHD t cases. Sounds like dodge had a pile of parts and just grabbed one when they needed it. My truck came with a 47re mated to a DLD but the nv4500 I put in was mated to a DHD and the output shaft is alot bigger on the DHD than the DLD.

[Haggar]

Lightnin,Looking at the parts lists (which encompasses GM, Dodge and Jeep), there were apparently 4 different input spline counts, and 2 different output spline (on main shaft) counts and two different lengths. I think the length difference is the DLD vs DHD. (making a real swag here!!! not known for a fact!!! Yet.) So according to my swag the DHD's came in two different output spline counts!!! (or the DLD did...) No wonder it is so confusing!!!! apparently the front case adapter in NOT interchangeable between the GM and CHry versions. GM is clocked a bit different.So far, so good!!! Drove it to work this morning, nothing apparently pouring out. Hope to hose down the underside this afternoon to really see. WOHOOOO!!!!Hag

[Rogan]

When I swapped my '96 auto trans w/241DLD for an NV4500 w/241DLD, I can tell you that the auto driveshaft's slip yoke on the rear shaft was considerably larger diameter than the manual 241's output shaft. I thought that was weird, and had to get a new yoke.I don't know what my '97 auto has on it for a tcase, but I'll check it out this weekend.My 01 6spd had a 241DHD.

[Haggar]

Interesting.....The parts list doesn't give diameters, but spline counts..... sounds like you ran into the same thing that lightnin did..... Weird.... Ok, searching through the quad4x4dotcom and drivetraindotcom There are 2 versions of the DHD and one of DLD with respect yoke diameter. By looking at the extension bushing diameters, the early DHD had the same slip yoke diameter as the DLD. Later DHD had a much larger slip yoke diameter. (sorry I don't have exact dimensions at the moment...) (now, just because the diameter was the same, it does not necessarily mean the spline count was the same....) (and from this, the DHD has 2 different extension housings....)wow.Hag

[CUMMINSDIESELPWR]

mine is a DHD 6 spd.

[one4autigers]

Hey guys. I bought my 01 ram 2500 bout 7 months ago its my first. The guy told me there was a problem with the 4wd but that all it needed was the front drive shaft. I did some looking and found that wouldn't be too expensive so I got him to knock some off the price of the truck. Well I got the truck home and started doing my homework and found out it has a 231hd tcase behind the 47 re. The front output shaft on the case is different than the 241 cases. The 231 doesn't use the double cardan joint. So there is at least 1 cummins with a 231 behind it. Question I have is if I buy a 23 spline 241 case will it bolt right up to my 47re. Thanks for the help By the way I don't know if that 231 came factory or was installed by someone else.

[Rogan]

231 is a gas tc. That's what was in my jeep Cherokees. Sent from my SPH-L710 using Tapatalk 2

[2000Ram2500]

On 9/13/2012 at 12:54 PM, Haggar said:

...I have found that many of the other NP 241s (especially the NP 241C that is a gm part) use the same extension housing, only differing in output seal. (the dodges use the extended boot, GM does not, I will probably use the Dodge part in my GM ones from now on!!!) There are two casting numbers that work on our (may be more, but these are the only ones that I have found.) C-16258 and C-17460. I had places tell me these were interchangeable and had places that said they absolutely were not. They are interchangeable to the best that I can measure. The 17460 is a modification of the 16258. I could be wrong, but the number is later and I consider it better. The only difference I can measure, is the output support bushing on the 17460 is not as close to the seal as found on the 16258. The 16258 is a PITA to remove the seal, as the seal tool does not have enough room to hook between the bushing the seal so you cannot hook the seal. The 17460 moved the bushing slightly toward the front of the vehicle. This does two things, there is more room for the oil between the seal and the bushing, and ease of replacement.One thing I have noticed, the 241 does not have as many drain back holes as the 231 (the 231 has what looks like 4 the 241 has only one). I lost the orientation of the drain back hole under the pilot bushing. I assume that the tail shaft extension fills with some fluid and the helix in the bushing will cause a pressure differential. edit: I found that the orientation is fixed. The 4 bolt pattern is not a square pattern. The tail shaft extension will fit properly in only one orientation.Check your bushing!!!!! I thought mine was "fine". Compared to the new one, it is 0.015" larger..... That may have been where that slight drive-line vibration was!!! should know this weekend.Hopefully I will no longer be a rolling superfund site!!!Will try to post a few pictures up.GL HTH Hag

 

 

recently cracked my rear extension housing. it is a DHD verified with the tag on the case

 

GM dealer in town gave me part numbers 15665311 (seal extension) and 15547441 (bearing retainer) and ive been able to find a C-16258 housing

 

The "PROS" say they wont interchange due to the bushing inside the housing being a different size and different output shaft and different output seal 

 

Found an ebay listing for the pair of GM housings just wanna verify before i order. the dodge one is available but expensive

[Joe_Pool]

My 2002 2500 has the 241DHD.  I am pretty sure the automatic units have a 23 spline input and the manual units have a 29 spline input.  If you have the plow prep package with an automatic you will usually have the 241DHD.

[2000Ram2500]

EDIT

 

completely deleted text i had before this because i just realized the OP had a DLD and i completely missed that before....

Edited April 7, 2020 by 2000Ram2500