I recently swapped out my stock three speed and D20 for an NP435 and a different D20. Periodically while driving, I will get a very audible vibration/whooshing sound coming from the drive train. I have removed the rear drive shaft and driven around in just front wheel drive and still have the problem. I don't know if it is the transmission, the transfer case, or possibly even the clutch. What are the symptoms of a pilot bushing going out? The vibration doesn't affect me being able to accelerate and it will continue even if I shift into neutral and coast. The vibration does slow down as I slow down. Really hoping to figure out what the heck this is without climbing back under there and swapping out transmissions and transfer cases until I find ones that work.......
A couple of other symptoms: If cruising on the highway without any problems, it will sometimes start. If I let it go without pulling over, it will go away, so it is just periodically happening.
A couple of other symptoms: If cruising on the highway without any problems, it will sometimes start. If I let it go without pulling over, it will go away, so it is just periodically happening.