4x4 Conversion Specific Questions

No Stormin, the TC do not all have different shafts splines by TC model but by the trani they were mated to. I don't know what a 241 D is or is from. All (98-02) of our trucks had had either 241DLD or 241DHD as options. DHD was probably std on 3500. Now the DHD does have a PTO access and a bigger input bearing and can have different input gear length and splines. There is three different lengths, mostly 2 are used. I think 23 spline on auto and 29 spline on manual, and most auto are the 4 1/4 length and manual 29 spline and may be 5 or 5 1/4 length. Internally the gears are the same but the DLD has the smaller bearing and chain.

I think Pirate 4x4 and other sites have a parts description and number chart with more detail.

Best to get a 01/02 47RE(match engine and PCM) 4x4 trani and a 241DHD from an auto(I do not think TC year matters.) But you want to match vacuum if you have CAD(4 post vacuum switch/plug. Does not matter if 2500 or 3500. DHD was common option on 2500. Or get a matched pair trani and TC with DLD.
If you do want to get a new output gear for the OD they are not likely available new and used is hard to find in good shape so do not mail order one. Trani shop can press them and R&R with new clutches for about 200-300 in an hour. I would do the new clutches either way if you have it. 2 sets fro 30 dollars each for parts, and an hour.

A lot of wholesale transmission parts stores like Transtar or PDQ dismantle and sell used trani and transfer case parts and rebuilt units.
Don't split transfer case "just to check it out". If it ain't broke , don't fix it.

The 1500 is probably a D or DLD, N or DHD. 1500 trani is different model. Input gear and output yokes may be different in 1500 TC, not sure.

Those that say that input splines are different for DLD and DHD are wrong. the input splines ae not dependent on which TC it is, they are dependent on which trani it is mated to auto or manual, not sure if 5 and 6 speeds are different, maybe different length. Is the OD housing different for 4x4 and 2x4 or is just the output shaft/gear different and the TC replaces the 2x4 tail shaft on the OD unit, Not sure you need a different OD case.

You need 47re, either TC DLD or DHD with proper input gear. Trani and engine/electronics year group must match. 98.5 /99 or 01/02, forget 00. no 99 trani's on 01/02 truck engine.
auto TC input gear should be 23 spline and short gear 4 1/4 inch length.

The straight 241 or 241d may be from 1500's or other brand or year trucks, maybe V-8 trucks, not 98.5 to 02 Cummins 2500/3500 trucks. They were all dld or dhd.