Engine/Transmission (1998.5 - 2002) HD X-case to replace LD x-case

[csutton7]

well last week I had to pull my light duty(DLD) transfer case out to see why my overdrive wasn't working(broken sprag gear), so I decided to put in my(waiting in the wings) heavy duty transfer case(DHD)--for those of you who don't know the HD case is one inch longer and has a larger output shaft than the LD case and a pto --I procured a driveshaft(via willyslover) from his wrecked '98 3500 qc long bed 5 speed(my truck is an auto)--his driveshaft is larger in diameter and was one inch shorter(short is good because of the extra inch on the HD case), but the short part is in the rear part of the driveshaft which requires you to adapt your carrier bearing bracket by one inch to make it fit, as the front part of the rear shaft is the same length as my OEM shaft--also the one inch diff means you need to extend your front shaft one inch--I'm not sure if this will be a problem down the road only time and some research will tell---chris

 

[MidwestMotorman]

Thanks for the info...

Thanks for the info. I have contemplating the swap in mine. Mine is a five speed, so it will be a little different. Is the front part of the rear driveshaft the only bigger part? Is the rear section(forward rear shaft) where it mates to the rear rear driveshaft (by the hanger bearing) any bigger? I guess the question is, is the rear part of the rear shaft exactly the same on the HD and LD transfer cases?



I know they are a balanced set. Did you compare the forward rear yokes side by side? Can one just swap yokes (or order new yoke) and not change the driveshaft, in the rear? Is the u-joint any different in width?



thanks again

 

[csutton7]

not to sure it there is a diff at the carrier bearing, but my guess is that there is as the whole 5 spd driveshaft was bigger in diameter than the OEM auto shaft-but since your already a stick you may have the larger diameter shaft to begin with(about 4")--I think you may have these prob's to deal with:



1) front driveshaft extended one inch(this may work out like mine and only time will tell- the only prob i see is upon full extension will it slip out)



2) will your rear driveshaft compress the one inch necessary due the added one inch of x-case-if not you'll need to rework your existing shaft or find one that will work and you will or may have to modify the carrier bearing mount



3) if your rear shaft will compress then you will need only to change the yoke on the front and possibly modify the carrier mount



the u-joints were the same size--



"if" I remember correctly willyslover had a Dana 80 and mine is the 70, so this is not a prob



there is a place in Oakland, CA that has the HD cases--they replace the chains with better(MORSE) quality and snap rings and maybe a couple of other things--they're around $1000 before shipping--they also replaced the input for me(auto transmission)---chris

 

[pcorssmit]

You can buy a 1" front driveshaft spacer from a 4 by shop, they go between the round 4 bolt flange on the front output and the shaft. Around $40-50. I ran one for a couple years in my Blazer w/no problems, I took it out when I replaced the front Dana 44 w/a 60.



Pete

 

[csutton7]

pcorssmit---thanks for that info-I was hoping that might be possible----chris

 

[Nordby]

I am converting an old ford to run a cummins/nv4500/np241 setup. The donor truck was an auto with a np241DHD, while the nv4500 I purchased had a np241DLD bolted to it.



Question for the mix and match crowd - it appears the 241DHD will bolt to the NV4500 just fine. Since I am already having to build driveshafts, I'm not concerned about the change in length front or rear. I'm more just concerned about the mating compatibility of the DHD t-case from an auto donor to the NV4500.



The DHD has 183K on it, and I know it works fine (thanks CJ, the donor owner). The DLD has 120K on it, but is more of an unknown. I'm assuming it is worth doing the swap for the stronger t-case.



Thanks for any info guys,

jon