where it connects to the hub or where the brake and rotor are is there a boot or what they call a cv axle (looks like a wrinkled TP)

 

I'm pretty sure no.
I see a u joint right next to the rotor.

 

you are feeling a difer between 4h & 4L

 

I think 4H is acting like 2H and 4L is acting like 4H

 

like angelic0 said there should be quite a noticible differince between the two. there could be a couple of issues don't think any are the transfer case most likely in the hub or the outside u joint. start small don't go to rebuilds yet.

 

Fireman Jon, all 4x4 Dodge Ram trucks come with a straight axle... and 4link suspension...

If you take it out of 4H/4L there's a vacuum operated actuator that disengages the front axle, so that the shaft does not rotate when you only have it in RWD...

I think your TC must be really messed up to have it engage 4H when the lever is set to 4L..

your U Joints on the driveshaft are most likely bad since the U Joints on the front axles are constantly moving, the clunking noise is most likely from the driveshaft, there's a double link joint at the TC and a regular joint at the front axle...

hope this clarifies your clunking issue, however i suggest taking the TC to a transmission shop to have it checked... you will find a significant difference in low range compared to high range...

 

u joint there easy to do my 96 did the same just replaced it

 

Thanks
I'm very diy and cash poor so I would like to look into fixing this myself.
u joints on driveshaft makes sense now that you put it that way and it seems like I was only really in 4x4 when in 4L.
I'll look at my vacuum lines today, it would be nice if it was that easy.

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Could I learn anything by disconnecting the front driveshaft and vacuum lines and shifting to 4x4 and driving with just the rears?
If I still get noise then I've probably narrowed it down to the transfer case.
Or would that not tell me anything?

 

Yes, if you simply remove the driveshaft...

Then you could tell if it was the front end u-joints... or the driveshaft...

if it still clunks remove the vacuum lines (bear in mind, if you disconnect the line on the axle, your AC/Ventilator will not work, you can't change if it blows to your feet or your windshield)

if that won't stop clunking... THEN it's your TC

 

just a thought make sure you lock the hubs.