Hi all, long time no post. How is everybody doing?

Problem: My 1998 SOHC 6 4x4 Explorer with auto trani is starting to make a weird noise when I load up the driveline when starting off hard- like having to pull out quickly into traffic. Under normal less stressful torque, everything is fine: transmission shifts good, engine runs great, nothing unusual. But when I have to step on the gas from a standstill, at about 10 to 20 mph I get this strange hard to describe, rasping pulsing thump-thump that lasts for a few thumps and then goes away with faster speeds. Its comes across like half noise and half vibration. I does not seem like I lose speed or torque when it happens, just feels like something it really complaining under load. My initial thought was a bad motor mount and I haven't completely rules that out, but I am now leaning more towards a worn front driveshaft CV joint- the one at the front of the transfer case. I have about 140,000 miles on the vehicle at present.

Any ideas as to what this may be or ways to figure out what it might be would be GREATLY appreciated.

Thanks in advance
JD

 

I never experienced the noise and vibration under heavy load, my CV joint just blew out on the front driveshaft, the bearing came apart going down the highway at 70 mph at 120k miles, talk about a vibration, i thought the whole thing was falling apart underneath me. I'm not saying its not the issue, but mine never hinted at anything being wrong, it just failed.