Engine/Transmission (1998.5 - 2002) New hum and vibration?? Help please

[KenHokie]

Just last night, the truck has developed a groaning sound and a high frequency vibration in the 900 - 1300 rpm range. The vibration can be felt in the steering wheel and in the brake pedal. It is much worst when the truck is cold (sitting out in 32 deg temps). When cold, while idling, there is no vibration but as soon as I either press on the brake or turn the wheel I feel it. It goes away when the brake is let off or I stop turning the wheel. Also, it goes away when the rpms get above 1500. My guess is that either the belt is slipping, more when cold, or my belt tensioner is going bad. Any and all ideas as to what this problem is would be appreciated.

 

[emjay]

Given that both the brakes and power steering put a load on the belt, it sounds like you're on the right track. Have you inspected the belt and tensioner?

 

[KenHokie]

I stopped by my local diesel shop at lunch to have them take a look at the truck. It turns out that I was wrong, the brakes and power steering are both run off of the power steering pump and it is geared into the front of the engine. Anyway, the power steering fluid was way low (below the dipstick). They added about a pint of fluid to top it off. Took the truck for a ride and the groaning and vibration is gone. Thats the good news. The bad news is that I know I filled up the PS pump when I changed the fluid to Valvoline Semi-Synthetic this past summer. That means I have a leak in the PS system somewhere! I guess I'll look for some dye to add and then look for the leak.

 

[KenHokie]

Well, I think I found the leak! Crawled under the truck last night and found the steering box was just dripping fluid. I checked the bolts on top of the box and one was loose . The service manual says 44 ft-lbs for these bolts and one was just about finger tight at best. I torqued all 4 bolts down and it appears to not be leaking anymore. I'll check it again in a few days. My guess is that this bolt was never tight from the factory and finally vibrated loose enough to begin leaking??? Now I'm wondering what else was put together wrong at the factory. .