Diff/Trans noise question?

Hey, I have a 64 F100 with a 4 speed. I have a noise that is coming from either the trans or the rear end. What is the best way to determine which is causing the noise? I can only seem to get this noise when it is under a load on the road. If I put it up on block, the noise goes away. Any help would be greatly appreciated.

Gerry

 

You might kick it out of gear and coast, and see if you hear a difference

 

Probably the easiest way would be to figure out if the noise is speed sensitive or not. Basically if the noise is constantly there under load without changing tone it would most likely be the rear, if it changed tone as you go through the gears I would look towards the trans. Not to say this is fool-proof but it will at least narrow it down for you.

 

Here is the deal when you are high gear ( 1 to 1) the presure on trans gears are mininal. Drive down road and listen to tone change getween 3rd and 4th .More noise 3rd is trans ,more noise 4th rear.Also you say noise changes on off gas,useally means rear.These are general rules but good ones .Been doing this 30 + years.

 

Once I,m moving, and the noise starts, it stays pretty constant reguardless of which gear or amount of gas/acceleration being applied. I am leaning more towrds the rear end because of this. Even with the clutch in, the noise remains. I have had rear ends make noise before, but this one is a little different, thats why I thougth I would pick some brains.

Thanks for the help!

Gerry

 

Thats def sounds like a rear. I have money on a pinion bearing but thats just me. Pull the driveshaft and jack it up. Turn the rear over with everything in it and start pulling parts til the noise stops. Start with wheel bearings (the easiest to change) and work your way to the harder parts to change.

 

Have you also checked the driveshaft and u-joints? Had a bad u-joint with needle bearings missing and made noise under load but none when load was light. Good luck