Ok, My truck has been getting gradually louder and louder and I need to fix it before it's too late. The whine seems to come from the tranny, but I'm told it could very well be the rearend. How do I figure out which it is without taking them both apart? Driveshaft going into rearend has about 1/2" of play maybe?? Nothing is leaking, everything has fluid. It didn't do it when I got it, but started after taking it on an hour road trip. Tranny shifts fine, ujoints are fine and everything else seems normal.

I can handle normal whine, but this is not normal. Oh, and it occasionally gets a really high pitched kind of whistle. It's normally at higher rpms and I'm thinking maybe it is the TOB?

The vibration/whine goes away when I let off the throttle

Truck is 78 f150 4x4 400 4spd

I've got spares of everything, but I don't wanna just start swapping things unless I have to. Any input is appreciated.

 

Worn u-joints can cause a vibration that will radiate throughout the entire vehicle. A clicking noise is also associated with worn u-joints.

Does the truck have a two piece driveshaft? If so, it has a driveshaft center support that includes a bearing that when worn, whines like a stuck pig.

The vibration/whine doesn't "go away" as it's there all the time. You just can't hear or feel it all the time. It was most likely present when you bought it, now it has become noticeable.

 

Thanks for the input, but I solved it today. I've had one of my 35's starting to get some belt seperation, and it's been getting gradually worse. I've been trying to find a replacement with no luck, so I kept driving with it (my spare is a 33 ) SO, today I moved the front (good) 35's to the rear and put two 33's I have laying around on the front until I can find a 35. The whine is gone. I guess the knot in the one rear tire put enough tension on the rearend to make it angry.

I do still have the high pitched whistle, but I"m pretty confident it's the TOB. I've got a new one ready to go in as soon as I have time to tear it apart again.

 

Well I spoke too soon. After driving all day, the noise/vibration came back. I'm getting tired of this game.

 

I would also check the pinion nut on the rearend yoke to make sure it's tight. Check the universal joints while you have them loose.

 

I checked the ujoints, they are all tight. I'll check the nut and see what else I can find. Thanks for the input