[Stocker]

You said you still have the HO52. I had a problem with my HO52 many years ago. Only thing I noticed was a faint growling noise from the rear of the truck, under deceleration. Only heard it at low speeds but the truck gets so loud as it speeds up that the noise may have been there but drowned out. Also never experimented with putting it in neutral so no help there. Local mechanic found a pitted pocket bearing on the end of the pinion gear. It's been good ever since.