noise in driveshaft

[pbd24]

My 2008 SE 4x4 crew cab auto has 10,000 mi on it. It was in the shop at 200 mi to have a u joint replaced and has been in three times since. I will try to explain the issue. When I am going about 40mph and the tranmission downshifts to third a get a noticable "bump". The tech that road tested with me said it was coming from the rear, maybe driveshaft, rearend, trany, etc. I called last night and they told me they did an upgrade on the onboard computer and it seems to be better. they tell me that it is a "characteristic" of the vehicle to have a "bump" like this. Any input would be very helpful

[travisl_2727]

my 05 had 25,000 miles on it and it started making that noise... nissan ended up replacing the whole driveshaft and the noise went away

[trainwreck]

replace the rear end, if not better move on to the rest ont the drive terrain.