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At speeds from around 20mph up my truck has been making a loud-cyclical-vibrating noise. It changes pitch and will disappear (once in a while) on corners and when I apply the brakes.
This weekend I changed the front rotors, pads, and calipers which were due anyway thinking they were part of the problem. No change in the sound. Any thoughts or suggestions?
The truck is an 80 1/2 ton 2wd with a 300-6 and SROD.
I have a 86 F-250 302 bored .030 over and 4wd and I am having the same vibrating noise problem right now also. It starts around 20 mph and gets really bad at around 50-55 mph at 2000 rpms. If I push it up to about 2500 rpms it begins to go away, I am thinking it is some sort of vibrating frequency but I can't figure out where it is coming from. It also goes away around some corners I just finished a frame- off resto on the truck also. The only thing I didn't change was the tranny and transfer-case. I have recieved advice that it might be a loose belt in the transfer case but I am not sure if that would cause this noise. It is almost unbearable when it reaches its max. Another thing that puzzles me is that the noise is intermittent, one week the truck runs great with no noise, then the next week the noise is back for who knows how long. Any input it appreciated.
Last edited by TWULFF44; Mar 19, 2007 at 05:47 PM.
Tire balance, poor tire wear, bearing failure, u-joint failure, rear bearing failure and driveshaft balance are somethings that come to mind.
1st balance and rotate the tires. If you still have a noise, see if it's worse when turning and to what direction. If not get the truck on a lift and drive it (carefully). Any driveshaft imbalance should show up quick. Wiggle the shaft to check u-joints.
If it's accelerating or coasting it could be a pinion bearing. Other sources are carrier and axle bearings.
I've got the flu so I hope that all makes some sense...
I should have mentioned that the bearings have been repacked. The tires are a couple years old and showing little or no wear. I am going to try lift the rear wheels off the ground and see if it does it sitting in the yard. Like TWULFF says the noise is nearly unbearable at its peak -- definetly increases the road rage after a bit.
I put the truck on jackstands yesterday and ran it up to speed where I have been having the noise issues. It turns out that the transfer case is bad. It is turning the front driveshaft when I am in 2H. I am going to look into what I can do about it without buying a whole new transfer case.
Sorry to hear about your tcase. I put mine up on jacks and it has to be in the front end. I am going to pull the wheels off and see what the bearings look like and then go from there.
I think I found my problem. Last night on the way home the truck suddenly lurched forward a bit and felt like it dropped down lower to the ground (it was nothing harsh) as I came to a stop a block from home. The steering was really tight as if the PS Pump quit. When I checked it out tonight the left front upright that holds the spring in place had broken from the frame. It looks like the rivets just popped loose.
Can I get some good grade 8 bolts and put this back in place or weld it? If anyone has any suggestions or advice about getting everything back together I would really appreciate it.
That there is craziness, never heard of ANYTHING like that happening.
Anyway, you can just bolt it all back together. The holes should all be 7/16. Bolt it and be sure to use washers and BE SURE you get them plenty tight enough. A grade 8 bolt will break from being too loose before it will ever think about it for being too tight (especially in the 7/16 range).