The front end of my 40 makes a solid thud sound when the axles is toqued with a hard R turn or change of approach / departure. It seems to come from the L side. There are no boises when I travel down the road. It handles fine. I tried 4wd and took it mellow on some dirt roads with no problems or no hard shift. I replaced the shocks (originals w dt3000s). I am going to lube it up this week. I do not think it is a wheel rub. I am concerned that it is a birf. I am thinking leafs / shackles / wheel bearing stuff maybe too. I do not see anything that looks worn or rubbed. And, again, it handles fine in both 2wd and 4wd. Any thoughts on what it might be or tests I can do to start ruling things out / in? To check birfs do I have to pull them ot is there a test I can do without busting up seals / puling axle? Thanks