When i get to 55 mph i hear i popping in the front.Ive replaced both cv joints and a wheel bearing,but it didnt help.Iinspected the spider gears but they were fine.I disconnected the front drive shaft now it doesnt pop. would you suggest the driveshaft or the transfer case to be the fault.has no shifting problems looking for suggestions or what i need to do to rule out the transfer case.u joints appear to be tight.

Check the front differential for proper spacing inside, also the bearings. Then check the homocinetic joint right behind the front diff. on the drive shaft. If all of them are fine, open the oil screw at the transfer case, drain the oil and check if there are some metal in it. After draining the oil out, use a flat screw driver, insert it into the transfer case (be careful!!) to locate the drive chain. check if there she is very loose ( if you can slide the chain more than 1/2" it need to be replaced). To rule out the transfer case, disconnect the rear drice shaft (U-Joint on rear diff. and then slide them out of the case), disconnect the front drice shaft right on the transfer case (U-Joint), disconnect the shifter and any wiring you find on the case, remove the bolts from the chassie and then remoce the bolts between the case and the auto transmission and slide the case backward till you have it in your hand. Install a new or rebuilt one the same way back, fill it with auto trasmssion fluid as told in the user manual. Do not overfill the case and do not use other fluid as in the user/service manual.